12-track-inspection-&-maint-jan-10.ppt

Module 12- Track Inspections & Maintenance*
Welcome to the Track Inspection portion of the Practical Guide to Railway Engineering Seminar.
My name is ____________________. I work for ___________________ and I have been in the railway industry for ________ years.
As you will see in the following slides, Track Inspection is one of the most important aspects of track maintenance.
Feel Free to ask questions throughout this segment as the presentation will be short and not extremely detailed.
COPYRIGHT © AREMA 2010
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Application of the Track Safety Standards
Specialized Inspection Vehicles
October 2007
The title of this Module is Track Inspection and Maintenance.
Track Inspection:
The purpose of track inspection in its many forms is to ensure that the track is first and foremost safe to operate and secondly, that it remains at the maintenance level desired.
We will look at how inspections are performed and why we do certain types of inspections.
We will explore the FRA Track Safety Standards to illustrate examples of track defects found through the various modes of inspection and how they are handled in the context of our operations.
And finally, we will touch upon the use of today’s technology to measure the quantitative attributes of the track structure.
Track Maintenance:
In this module, we wish to gain some familiarity with basic elements of railway track maintenance. It is important that you have an understanding of how we maintain railway functions so that your design and construction projects are seamless with our operations. Although you may not be supervising rail relay or timbering gangs, you may have to integrate these functions into your project in order to complete it.
At the conclusion, you will hopefully have a basic understanding of track inspection and maintenance practices and how it relates to overall operations. We want you to remember that what you build, we have to maintain.
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First and Last “Line of Defense” against track related derailments
Initial phase of planning for maintenance activities and future track upgrade programs
Public and employee safety
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Besides being a regulatory requirement, track inspections are a vital part of ongoing track maintenance, and are often the first and last line of defense against track related derailments.
Inspections are also an important part of the track maintenance planning process. As will be evident in the following slides, specific methods of inspection are utilized to plan future maintenance activities.
Most importantly, quality track inspections are essential in order to protect our railroad employees and the public at large from track related train accidents.
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Hi-rail Inspections
Walking Inspections
Train Inspections
Each of these will be discussed separately beginning with the Hyrail.
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Inspection By Hi-rail
Hi-Rail
The hi-rail is a versatile vehicle that allows the inspector to traverse the track in one direction and return by road
Provides flexibility/versatility
Most often one, and sometimes two Inspectors observing the track
Scheduled per regulatory requirement and/or company policy
Visual detection of defects
“Feel” and sound of the track that may indicate the presence of a substandard condition
October 2007
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The Hi-rail inspection - Is conducted most often as it allows the inspector to cover more track than if walking, but also allows him/her to view the track close enough to detect track defects. Most of the “main track” required inspections are performed by hi-rail.
Since regulations were introduced requiring minimum inspection frequencies (in some cases 2 or more times per week), the hi-rail vehicle has become an indispensable asset for the track inspector. The on-rail-or-road flexibility of the hi-rail has drastically reduced the “unproductive time” of waiting in remote sidings for trains or work crews to clear. Often the inspector can plan his/her inspection around trains and maintenance crews as they are able to remove the hi-rail at road crossings and travel to another section of the railway to continue on with their inspection.
In addition to the visual aspect of an inspection, a seasoned track inspector will use other senses during the course of an inspection including the “feel” of the track and distinct “sounds” that may indicate an abnormal condition.
Some primary inspection items include; Broken rails or rails pulled apart at a joint, unusual marks on the rail, broken or missing bolts, general surface and alignment deviations, standing water in ditches, signs of unstable grade, ballast condition, clusters of defective ties, high spikes or missing fasteners, damage to railway signs and signals, general condition of turnouts, condition of road crossing surfaces, and several other items far too numerous to cover in this session.
Track inspections are most often performed by one inspector, but at times they may be accompanied by an assistant or track foreman.
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Quantify defects with physical measurements
Planned at various times of year, or;
Company policy may dictate an annual walking inspection.
Regulatory requirement for inspecting turnouts, track crossings and lift rail assemblies or other transition devices on moveable bridges to be performed “on foot”
Walking Inspections
October 2007
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Secondly, The Walking Inspection - May be performed for various reasons, numerous times a year, on any given track. Some railroads may even require their inspectors to cover the entire main track territory on foot every year. For the most part however, walking inspections are performed when it is necessary to get a closer look at a particular segment or aspect of the track structure.
Walking inspections are often an integral part of planning major maintenance programs such as rail and tie replacements.
In addition, FRA Track Safety Standards and Transport Canada – Track Safety Rules dictate that; Inspection of switches, track crossings, and lift rail assemblies or other transition devices on moveable bridges”, shall be inspected “on foot” (walking) at least monthly.
The on foot inspection is stipulated for good reason. Realistically, the measurements required for an adequate inspection of these types of track works can only be done from the ground with a tape measure or other measuring device in hand. In addition, the several moving parts of a turnout or lift assembly need a close look for signs of wear and proper fit. Simply put, this can only be accomplished by getting down – and often dirty - with your track.
It cannot be stated enough that an “on foot” inspection can reveal conditions that may never be detected from a hi-rail vehicle.
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Provides a “feel” of the track under loaded conditions
Frequency depends on amount and type of train traffic, anywhere from twice annually to monthly
No regulatory requirement – Company Policy
Train Inspection
October 2007
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And lastly, The Train Inspection – Performed to get an overall indication of the track geometry under load and observe the ride quality, primarily for passenger trains, but also freights.
The availability and flexibility of hi-rail vehicles, in addition to advancements in track geometry vehicles, have diminished the need for “train ride” inspections.
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Emergency (Weather related, Incidents/Accidents)
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There are also three types or “reasons” for a Track Inspection. Once again, each will be discussed individually.
Scheduled inspections – Covering compliance with regulatory and company standards
Special Inspections – Covering specific locations or conditions as well as Emergency situations
Specialized Vehicle Inspections – Specifically Rail Flaw and Track Geometry test vehicles
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Regulated, Mandatory inspection of Main track and sidings (Hi-rail or Walking)
Monthly Inspection of “Other than Main” track, Turnouts & Special Track Work (Walking)
FRA/Transport Canada outlines minimum inspection frequencies
Report of tracks inspected, conditions found and actions taken are completed during the inspection.
Scheduled Inspections
October 2007
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Scheduled Inspections are for the most part conducted as per regulatory requirements, which vary in frequency depending on the class of track and the amount of tonnage hauled over a segment of track.
These scheduled, or “routine” inspections are performed primarily by hi-rail vehicle, although as previously discussed, turnout and other track work inspections are conducted on foot.
Track Work, as defined in regulations includes; Track Crossings at Grade (diamonds), Lift Rail Assemblies (Drawbridges), or other transition devices on moveable bridges.
A railway company may initiate more frequent scheduled inspections than called for by regulation. However, minimum frequencies as outlined by regulation must be followed.
In addition to the inspection itself, there are reporting requirements outlined by the regulation, which we will cover in more detail in a few minutes.
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Track Safety Standards
GENERAL
ROADBED
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The Federal Railroad Administration sets minimum standards for the maintenance and inspection of track in 46 CFR 213 Track Safety Standards. In most cases but not all, the criteria are speed oriented, meaning the tolerances become more restrictive as the speed goes up. These standards are far below what are deemed good maintenance or design practices. In fact, if one uses the FRA Track Safety Standards as a maintenance standard, it is almost certain the railroad will not be operating at that speed for very long. The Track Safety Standards are applicable to any railroad deemed part of the general transportation system (interchanging freight cars to and from their trackage). Most rapid transit systems, industrial plant trackage and railway museums are not part of the general transportation system; however, many adopt the Track Safety Standards as a minimum.
The Track Safety Standards are broken up into 6 primary segments. Subparts A – F are concerned with freight train speeds up to 80 MPH and passenger speeds up to 90 MPH. Additional more restrictive standards are published for passenger trains operating at speeds in excess of 90 MPH as is done by Amtrak in the Northeast Corridor or on the west coast.
Canadians under the auspices of Transport Canada utilize a similar set of minimum standards with but a few minor exceptions.
AREMA FRA 213 CLASS
Quantitative
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The FRA Track Safety Standards classifies defects in one of two ways.
As already mentioned, most defects are tied to the speed of operation. Acceptable and measurable parameters are compared against established measurements or allowable deviations ranges of speed. As the speed ranges increase, the tolerances or acceptable deviations become more restrictive. Should the track structure not meet up with the requirements, one must either repair the defect, restrict the speed down to a class of track that finds the measurement made acceptable, or remove the track from train operations until the defect is repaired to at least acceptable parameters for the bottom range of speed. (Gage, alignment. Surface. Etc. are examples
Other defects are not tied to a specific speed range, but when found require action. For example rail defect remedial action is based on the size of the defect. There are non-class specific defects that are not measurable, but are dependent on whether or not the specific function is capable of performing its task. Drainage and vegetation are examples. Either the drainage structure is capable of performing it’s task or it isn’t. These defects may be somewhat subjective and often the presence of other related defects are used to determine whether a qualitative non-class specific defect exists. Per the FRA/Transport Canada, a defect may exist if even though in isolation individual parameters meet the minimum requirements, but combined together a condition exists that may peril train operations (213.1).
Track inspectors locate defects primarily through visual observations. It may be readily apparent such as the bolts sheared and the rails pulled apart at a joint or a broken rail. Other defects may not be as readily apparent and are determined through sophisticated machines, e.g. ultra-sonic inspection of the rail.
In any case, once a defect is determined to exist one of the three R’s (Repair, Restrict, Remove) must be applied before the first train.
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213.7 Designation of Qualified Persons to Supervise Renewal & Inspect Track
213.13 Measuring Track Not Under Load
213.15 Penalties
213.17 Waivers
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This section of the standards is concerned with the regulatory aspects of the regulation. The speeds associated with each class of track are defined for both freight and passenger operations. These are the maximum speeds that may be operated for a given class of track. Should the speed operated be between two class of track maximum permissible speeds, the class of track is automatically designated as the next higher class of track. Railroads, upon discovering a defect not in compliance with the class of track for the speed which they desire to operate, must immediately repair the defect or restrict the speed to a class of track to which they will be in compliance or remove the track from service until the repair is completed.
The FRA denotes a special class of track known as Excepted Track. Many of the smaller short lines are formerly unprofitable branch lines spun off from Class 1’s. Their inability to generate adequate revenues in the past relegated them to receive little if any capital improvement dollars. In many cases, they will not meet the minimum requirements for Class 1 track. The owners will not have access to the funds required to bring the track in compliance with Class 1 track. Yet these short lines are indispensable to the vitality of the nation’s economy. The FRA permits these railroads to designate trackage not meeting Class 1 requirements as Excepted Track. Such railways may operate at Class 1 speeds (10 MPH) without bringing the track into compliance. There are restrictions regarding the movement of hazardous material cars and passenger trains, minimum spacing required between excepted track and track operated at higher than Class 1 speeds as well as a maximum permissible value for gage.
This subpart of the Standards also defines the criteria associated with who can supervise restoration or renewal of track and who can inspect track.
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Subpart B, Roadbed describes the minimum requirements for roadbed and area immediately adjacent to the roadbed. This section of the Standards is not class specific – meaning there is not a prescribed remedial action for a given defect. Qualified railway personnel determine an appropriate remedial action for drainage or vegetation related defects based on their experience and the conditions peculiar to a given operating situation.
The FRA stipulates that each drainage or water carrying facility under or immediately adjacent to the roadbed must be maintained and kept free of obstruction to accommodate expected water flow for the concerned area.
The FRA further requires that vegetation be controlled so that it does not become a fire hazard to track carrying structures; obstruct visibility of signs and signals along the right-of-way and at highway rail crossings; interfere with railroad employees performing their trackside duties or prevent them from inspecting moving equipment from their normal duty stations; or prevent signal and communication lines from functioning.
Ask: Based on the photos depicted on the slide, are there defects present?
Answer: Certainly, the presence of sanding water reflects a blocked or collapsed culvert, The vegetation under the bridge could become a fire hazard during the dry months.
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213.63 Surface
October 2007
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Subpart C, Track Geometry deals with how the car wheel-sets interact with the track structure. The minimum requirements for gage, alinement, surface of the track, elevation of outer rails in curved track and speed limitations in curves are defined.
We will provide special focus on gage, alinement and the special parameters associated with surface. We have already dealt in a previous module with the maximum permissible speed that can be operated around curves based on elevation and degree of curvature.
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4
4
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Gage refers to the distance measured between the heads of the two rails at right angles to the rails in a plane 5/8” below the top of the head. Track is built in North America, with but few exceptions on transit and museum lines to a standard gage of 56-1/2” (4’ 8-1/2”). The inside face of wheel to inside face of wheel dimension is 53-1/4” (4’ 5-1/4”). This permits some movement of the wheel to enable the wheel flanges to float between the two rail heads and yet for the wheel tread to still ride on the rail. However when the gage becomes two wide, the wheels may literally drop in. As a train moves down the railroad, the wheels tend to hunt back and forth between the gage corners of the rail. Each time the wheel flange impacts the rail gage corner, a lateral load is applied to the rail. As the speeds increase, this lateral load goes up by a factor of the square. As the wheel runs around a curve, centrifugal force causes the wheel flange to ride up against the gage corner of the outer or high rail – again imparting significant lateral loading. This lateral loading eventually causes spike hole enlargement and tie deterioration. The end result is wide gage.
The FRA Track Safety Standards also specifies minimum gage. Gage too tight can cause the wheel to climb the rail and thereby derail.
Typically, the wheels will fall in when the gage under load exceeds 2”. The FRA sets a maximum permissible wide gage for Excepted Track at 1-3/4”. There is no relief from this provision for even Excepted Track.
Gage defects are a constant source of headaches for railway engineers.
Ask: Can you spot the defect in the photo. The sharp kink in the closure rail is wide gage. This is a frequent spot for gage problems in turnouts.
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Alinement refers to the horizontal positioning of the track structure. In tangent track, the track is straight if we lay a string of any length along the gage face of the rail and the string touches the rail at every point. For referencing purposes, a 62’ string is stretched along the gage face of the rail with the midpoint of the string at the location that by eye appears to be the most out of line. The mid-ordinate distance between the string and the gage corner of the rail – 5/8” down represents the maximum deviation from the desired 0”. The Track Safety Standards specifies for a given Class of track the maximum deviation permissible for tangent track. If the mid-ordinate measurement exceeds that value, railways must either correct the alinement defect or reduce to a class of track for which the mid-ordinate measurement read is in compliance.
In curves, there should be a mid-ordinate value read when using the 62’ string. Remember, the mid-ordinate value read at the midpoint of a string in inches for a 62’ chord reflects the actual degree of curvature at that spot. However the difference in the actual mid-ordinate value read and the average value for the curve is the deviation. The deviation exceeding the value found in the Alinement Table for the 62’ chord for a given class of track will require that the defect be corrected or the speed of the track be dropped to a speed which it will be in compliance. For Classes 3 through 5 track, the FRA also requires that one use a 31’ chord to check for deviation in addition to the 62’ chord. It is theoretically possible to hide a short sharp line spot inside of a longer badly out of line location. This short sharp spot might not be revealed with the longer chord but will be evident with the shorter chord.
Tangent Track
Curved Track
Class of Track
The deviation of the mid-offset from a 62 foot line may not be more than
The deviation of the mid-ordinate from a 31 foot chord may not be more than
The deviation of the mid-ordinate from a 62 foot chord may not be more than
Class 1
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Surface refers to the relationship defined by the longitudinal and transverse relationship of one rail to the other. In most cases, permissible surface deviations are much more restrictive than for alinement and are a leading cause of derailments.
We will discuss several critical surface parameters including run-off, profile, deviation from uniform crosslevel in tangent and maximum reverse crosslevel in curves, difference in crosslevel within 62’ or warp, and harmonics.
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Runoff conditions are usually a result of some kind of track maintenance activity. Trains encountering a ramp (up or down) will experience a vertical pitch or bounce if the runoff is too abrupt or short. As in the more general profile parameter, damage to car components, damage to customer’s freight, undesirable brake applications, or derailments may occur.
Run-off is measured by stretching a 62’ string along the top of the rail with the midpoint of the string at the point that the rail begins to ramp down or up. The remainder of the string is stretched out over the rail ramping up or down with the first 31’ of string just maintaining contact with the head of the rail. The distance from the end of the string down to the rail then becomes the run-off in 31’ Maximum permissible values for each class of track are provided in the surface table
Run-off in this photo is located at the transition point from an open deck bridge to a ballast decked bridge. Run-off is commonly found off the ends of bridges where the track modulus for more rigid bridge structure transitions to the smaller modulus of the track itself.
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Trains encountering short sags or humps in the track can cause vertical separation of couplers, broken springs, bolsters, and truck frames, as well as damaging customer’s freight. Sags can result from mud spots, or develop at the ends of fixed structures, i.e., bridges, highway grade crossing and track crossing frogs.
The profile measurement is made along one rail by stretching a 62 foot string on the top of the rail and placing the midpoint of a 62-foot chord at the point of concern, irrespective of vertical curves. Then the distance between the string at the mid point and the top of the rail is measured. The measured deviation is compared to the maximum permitted for the appropriate class of track. Profile may also be a track hump cause by a frost heave or other occurrence. The most common profile problems found are sags.
The profile in the photo above is probably the result of a subgrade failure.
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The next surface parameter is deviation in crosslevel in tangent track and maximum allowable reverse elevation in curves. These are single spot measurements. In tangent track, the crosslevel reading should be 0”. Anything else is a deviation and is compared to the table for the appropriate remedial action. The same table is used to determine the maximum allowable reverse elevation reading. Remember, in both cases to add any movement under load.
Ask the class how to measure the crosslevel at this location.
Ask the class what defects might exist at this location and what is the root cause of the problems at this location.
Also note to the class that conditions such as this at an insulated joint can cause signal failures and premature failure of the insulated joint. The joints are expensive and stopping trains due to signal failures is very expensive.
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Difference In Crosslevel
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Difference in crosslevel or warp compares how the crosslevel changes from one spot to another anywhere within 62’ on tangents, curves, and spirals. It is a reflection of what the car experiences as the lead wheels react to a low joint on one rail simultaneously to the rear truck wheels reacting to a low joint on the opposite rail. The twist experienced by the car can cause wheel lift with a resulting derailment. Warp is calculated by finding the two largest crosslevel readings within 62’ on opposite rails and adding them up to get a difference in crosslevel reading or finding the largest and smallest crosslevel readings on the same rail within 62’ and subtracting the readings to obtain the difference in crosslevel. These values are then compared to the maximum permissible values found in the Surface Table.
Although warp in the field is probably the most difficult surface deviation to detect, it is generally the most limiting and should be always checked when low joints are present.
In the slide photo, we see a very low joint in the far rail and another low joint in the near rail. Crosslevel readings would be taken at each joint, potential movement under load added and the two crosslevel readings added to determine the difference in crosslevel or warp.
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For any body in motion, there is a critical speed at which if imparted harmonic movement of a given frequency, resonance will occur with the resulting amplitude becoming progressively larger until failure occurs. For many freight cars, they can go into resonance at speeds between 17 – 22 MPH if they encounter a series of low joints on opposite rails with a difference in crosslevel of 1-1/4”. This surface condition is deemed possible if 7 consecutive low joints (6 difference in crosslevel readings) are all found to have a difference in crosslevel greater than 1-1/4”. This condition is not applicable for joint staggers less than 10' or for 80' rails. Joints outside normal stagger, insulated joints, plugs, etc., are not included as harmonic joints. It does not apply to CWR. The remedial action required is to either raise one or more of the low joints to break the pattern or reduce the speed to 10 MPH (below the critical speed required for resonance. Extreme harmonic conditions can cause high center of gravity cars (loaded covered hoppers, etc.) to rock off and derail.
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October 2007
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Subpart D, Track Structure prescribes the minimum requirements for ballast, crossties, track assembly fittings and the physical conditions of the rails. The remedial actions are a mixture of type and course of action. For some like ballast, there is no specified remedial action. For rail defects, there are specified remedial actions, but they are independent of speed. Others like mismatch between gage and tread faces are class specific.
We will concern ourselves with two sections of Subpart D: Crossties and Defective Rail as both are essential components of the track structure.
Top Photo – 213.137(c) worn tread of frog requiring 10 mph slow order.
Bottom photo – 213.135(b) switch point not properly fitting against the stock rail.
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PER 39’ RAIL LENGTH
Definition of Defective Tie
Joint Tie Conditions Fulfilled
Non-Defective Ties Effectively Distributed
Tangent track and
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The crossties in the track serve to provide three functions. First to maintain gage, second to maintain surface and third to maintain alinement. In newly constructed track, all ties are serviceable. Immediately after the track is placed in service, this condition no longer holds true. Not every tie has to be capable of performing each of the three functions. But the aggregate system must do so in order to carry the applied loads.
What is a defective tie? In general any tie that is broken through, split or otherwise impaired to the extent that the crossties will allow ballast to work through, or will not hold spikes or rail fasteners, or so deteriorated that the tie plate or base of the rail can move laterally more than 1/ 2 inch relative to the crossties or cut by the tie plate through more than 40% of the crossties thickness is considered to not be an effective crosstie.
The FRA defines the minimum number of effective ties per 39’ that must be present. Note: The average rail length contains 22 – 24 ties depending on tie spacing. Thus only ½ the ties in a rail length for Class 4 or 5 track need be serviceable. The requirements are somewhat more restrictive in turnouts and curves of 2 degrees or greater.
The FRA further says the serviceable ties must be effectively distributed. Although that does not mean evenly spaced; there does have to be some common sense distribution throughout the entire rail length.
Joints are a particularly weak area in the track structure. Special attention dependent on the class of track is specified for distances between centerline of joint and the centerline of the closest non-defective tie
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Defects Longitudinal
Split Web & Piped Rail
October 2007
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The process of locating and removing a defective rail prior to a train finding it is obviously a high priority for any railway. Ultrasonic or combination ultrasonic and electro-induction testing of mainline rail is required by the FRA for railways operating above Class 2 speeds. The frequency of testing is determined by whether or not passenger trains operate over it, the designated class of track and the annual tonnage operated over the track segment. Class 1, large regional and commuter railways test at much higher frequencies than the FRA requirements.
Not all defective rails are located by test vehicles. Many defects have a signature trail that a sharp eye performing routine track inspection can pick up. Some break but are detected by the fail-safe system provided by the track circuit in trackage controlled by a signal system. Regardless all rail defects are dangerous and must be removed from the track. The FRA remedial actions are not class specific. The particular remedial action is governed by the size or length of the defect and its nature. Any complete breakout in the rail requires that the rail be immediately changed prior to allowing a train over it, or that the track be removed from service or that every movement over the broken rail be supervised by a qualified employee at walking speed. Track designated as Excepted Track is exempt from the remedial actions required for defective rails, but there is a presumption that movement over the rail will not occur unless it is safe to do so. Remember speeds associated with Excepted Track are limited to 10 MPH and passenger trains are not permitted.
Rail defects can be broken down into two major classifications: defects that represent a percentage of the cross-sectional area of the head and defects that represent a given longitudinal length.
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Transverse & Compound Fissures
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There are many different type of rail defects. The transverse fissure and compound fissure are examples of two of the most dangerous defects. Transverse fissures begin because of a trapped inclusion or hydrogen bubble located in the head. They are a very dangerous defect in that there are no visible indications until the crack reaches the exterior of the head. As older rail rolled prior to 1943 (advent of controlled cooling) are phased out, their frequency of appearance is declining. The defect can be recognized by its center nucleus surrounded by rings much like that of a tree. When it breaks, the rail frequently shatters with large chunks breaking out although the primary break is in a transverse plane.
A compound fissure is similar to a transverse fissure except it starts in a horizontal plane and then progresses downward.
The required remedial action for defects affecting less than 70% of the head is relatively innocuous – a qualified individual limit the speed to 30 MPH or the timetable speed of the track, whichever is less, transverse defects of either type should be immediately removed from the track upon their discovery.
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Detail fractures look like a transverse defect, but originates from the outside gage corner of the rail and usually starts from shells. A dark half-moon shaped spot at the gage corner of the rail is a good indication that a Detail Fracture is forming. These defects are quite common and are a reflection of the heavy tonnage that exists on North American railroads today.
When these defects break it quite often results in a derailment because a piece of rail will completely break out of the track. Rail detector cars often have trouble detecting this defect.
Engine burn fractures originate out of an engine burn on a rail from wheel slippage of a locomotive. The presence of a burn on the rail is not indicative of a fracture. They originate often from a burn not properly repaired. Inadequate grinding to get to the bottom of the burn and to remove the micro-cracks prior to laying down weld bead is often the cause. .A hairline crack on the side of the head, in the immediate vicinity of an engine burn on the surface, and at right angles to the running surface may be visible. The crack may be visible on either the field or gage side of the head.
Defective welds are caused by the incomplete penetration of weld metal between rail ends, lack of fusion between weld metal and the rail ends, entrainment of slag or sand during the thermit welding process, shrinkage cracking from running a train too soon after weld completion or fatigue from tonnage operated over it. The defect involves a field or plant weld with discontinuities or pockets exceeding 5% of the rail head area individually or 10% in the aggregate. It is oriented in the transverse plane, may originate in the head, web or base and may progress from the defect into either or both rail ends.
These defects complete the defects associated with affecting a percentage of the cross-sectional area of the rail.
Other types of defects include: horizontal and vertical split heads, head & web separations, split webs, piped rails, bolt hole cracks, broken base, flattened rail and ordinary break.
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213.205 Derails
Clearly Visible
Properly Installed for Designated Rail Section
October 2007
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Derails are provide with their own subpart – Subpart E. The intended purpose of the derail is to direct the wheel of a moving car, moving along a path that it shouldn’t be going, off of the rail at slow speeds away from danger of fouling a high speed track. As such derails are only used in slow speed non-controlled track as found in yards and sidings. The FRA Standards only specifies what attributes the derail must possess. The derail must be clearly visible to an approaching train, must not have lost motion between the throw lever and the derail mechanism, must operate in the manner it was intended and must be installed per the manufacturer’s instructions. Derails are sized by the rail section that they will be used on. Derail sized for a smaller rail section than the section in use may not cover the entire head of the rail and may not derail an approaching car. A derail too large for the rail section will not be properly supported by the rail and may break under load rather than derailing the car.
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Tie defect Counts
Rail Wear Measurements
Rail Grinding Requirements
often be anticipated)
Special Inspection (Specific)
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There are basically two types of Special Inspections. The first we will discuss is a special inspection that is planned, scheduled and specific in scope.
Planned special inspections are performed for a number of reasons at various times of the year. Depending on the geographic region and the type of Railroad operation, there are many different conditions that may warrant a special inspection. For instance, an inspector may plan a special inspection of culverts in the late winter in preparation for the expected water flow from the spring thaw or in advance of the heavy rain fall season depending on what part of the country they are in. An inspector may also plan a periodic inspection of areas where there are known problems related to the track grade, or an annual audit of “at grade road crossings” to determine maintenance requirements.
“Detailed” Turnout and Track Crossing inspections are a type of special planned inspection. Most railways preferring to conduct them in the spring or fall, and sometimes both.
Many planned inspections are done in preparation for upcoming maintenance programs or for future planned upgrades to the track such as major tie renewal or rail relay programs. These inspections will involve measurements, in the case of rail replacement or rail grinding programs. For tie renewals it will involve actual mile-by-mile counts of defective ties.
An example of a special inspection that cannot be pre-planned, but can be anticipated for certain times of year are those that are brought on by extreme heat or cold. The majority of Railroad companies have high and low temperature thresholds that once reached, will initiate a special inspection.
Those that cannot be planned and are also unpredictable, are considered “emergency” special inspections (next slide)
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Emergency Special Inspections are triggered by unplanned events such as severe weather and other natural anomalies such as earthquakes.
FRA 213.239 states: In the event of fire, flood, severe storm, or any other occurrence which might have damaged the track structure, a special inspection shall be made of the track involved as soon as possible after the occurrence and, if possible, before the operation of any train over that track.
The photographs shown on this slide are examples of grade failures resulting from heavy or prolonged rainfall.
Also unpredictable, especially in mountainous areas are problems such as rockslides, avalanche and mudslides caused by snowmelt high above the track.
Tornados and High winds can often leave large trees and other debris on the track.
Inspecting damage caused by an earthquake is especially difficult, as there is no way to positively ascertain the area affected and a special inspection may be required on one or more track inspectors entire territory to ensure the track grade and structures have not been adversely affected.
Emergency Inspections may also need to be conducted following reports of vandalism, track or signal damage as a result of a vehicle collision with a train, or other types of human factor related incidents.
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List all deviations and the corrective action
Kept on file for 1 year
Type of inspection indicated on report
Signed & dated
Inspection Records
October 2007
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As the oft heard saying goes – The job is not finished until the paperwork is done!
All required track inspections, including turnout and special inspections, are recorded on a Track Inspection Report, and kept on file for one year.
The reports are to be completed on the same day as the inspection and require the following information:
The date of the inspection
The track or tracks inspected
The location and nature of any FRA deviations found and the corrective action taken
And finally the report must be signed by the track inspector.
Some Class I railroads have adopted the use of “Electronic” track Inspection Reports which are produced “on the fly” by track inspectors using lap-top computers or Palm Pilots.
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Scheduled
Internal search for rail defects using NDT “Ultra-sonic testing equipment
Specialized Equipment & Training required
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Although very effective, visual track inspections are limited when it comes to detecting defects in the rail itself, or track surface defects that only manifest themselves under loaded conditions. Technology has come a long way to fill the gaps where physical limitations have left off and have become a vital tool, enhancing the complete inspection process.
Rail Flaw Detection Vehicles with ultrasonic equipment and trained operators are capable of detecting internal flaws in the rail that the track inspector alone may not find until completely broken out or a break is imminent.
Prudent Railway companies will plan and schedule rail flaw detection on a regular basis, the testing frequency based on the amount of tonnage handled, rail size and condition, occurrence of field service failures (broken rails) and other criteria.
Regulations specify rail inspection frequencies for Class 4 and 5 track (and in Canada - Class 6 track), and Class 3 track on which passenger trains operate, however several railways are adopting a more aggressive strategy against broken rail derailments by testing more often.
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Railway Engineering budgets are broken down into two segments – normal day to day maintenance covered under the Operating budget and special capital improvement projects covered under AFE’s (Authority For Expenditure) which is programmed beyond budgeted operating expenses.
Normal maintenance work is typically directed at the division level by the division engineer rather than by corporate staff. A large Class 1 railway may have between 9 and 15 divisions encompassing half of the United States or Canada. The divisions are further broken down into territories or subdivisions with the work planned and directly supervised by local officer level supervision. Each local supervisor will supervise multiple gangs or teams who actually perform the work under the immediate direction of a foreman. Virtually all of the Class 1, larger regional and commuter/transit railways work under a labor agreement. Many of the smaller short lines are not unionized. The agreement between the carrier and the labor organization spells out the specific work that a craft can perform under normal operations and the conditions upon which that work will be performed. The agreements are designed to accommodate the normal maintenance functions typically required to maintain the infrastructure.
Normal maintenance is designed to keep the railway up to its standards between major capital improvement or rehabilitation programs. Production rail and tie renewal, undercutting, complete bridge structure replacement, out-of-face replacement of catenary wire or conversion of a signal system from pole line wire to microprocessor based coded track is not considered normal maintenance. The primary crafts performing normal maintenance can be broken down into Track, Bridge & Building, Signal & Communications and on passenger railways, Electrical.
On an electrified railway, the maintenance of the overhead catenary or third rail system is accomplished by an electrical gang. In third rail territory, the gang maintains and replaces/installs the heavy traction bonds between rail ends, maintains impedance bonds, replaces pitted third rail, and maintains the extensive cabling required to energize the third rail.
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Basic Track Work
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Basic track maintenance is accomplished by the section gang which consists of 2 to 6 employees covering any where between 20 to 200 miles depending on annual train tonnage operated over the territory, number of turnouts and frequency of operation. The section gang performs the day to day maintenance required to keep the track operable. This includes spotting in ties on a localized basis, raising low spots, changing out defective rail, adjusting the neutral temperature of CWR, performing mowing or brush cutting operations, providing flag protection for contractors, maintaining switches and crossing diamonds, cleaning snow from switches, repairing road crossing surfaces and many other functions required to keep the track safe for the movement of trains at timetable speeds. The section gang is often equipped with a specialized hy-rail vehicle designed to permit ready access to any track segment of the section. Hydraulic tools along with truck mounted electric or hydraulic one-ton cranes facilitate the performance of heavy and tedious tasks that can now be done by 1/3 to ¼ the number of men previously required. The sections on a territory or subdivision(s) are supervised by an officer titled as a roadmaster or track supervisor or manager track maintenance.
The section is also called upon to respond to derailments and other natural emergencies such as floods, washouts, slope failures, rock slides, etc. The section will work around the clock to restore train operations. On any railway, no expense is spared or effort required too great when train operations have been disrupted.
The section will also be called upon to provide support for other track capital improvement projects. Sections may join together to accomplish larger track projects such as road crossing renewals.
Each subdivision may possess one or more specialized machine operators. They operate rail based cranes, backhoes, specialized track equipment and any other specialty equipment pieces.
Track welders are another subgroup member of the Track Department. They build up rail ends; repair manganese frog castings; grind switch point, stock rail, frog and crossing diamond overflow as well as thermit weld together CWR rail strings.
Work equipment mechanics are the last subgroup. They are charged with keeping the divisions machinery operable.
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Basic Signal Work
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Normal signal maintenance is split between the signal maintainers and the signal gangs. A signal maintainer is assigned to a territory, the length of which is a function of the number of crossing warning devices, interlockings, switches and signal appliances found on the territory. The maintainer is responsible for repairing broken crossing gates, changing bulbs in signals, replacing broken bond wires at rail ends, performing monthly Federal mandated crossing warning device tests, adjusting track resistors and other track circuit functions, maintaining track batteries and power supplies, maintaining and adjusting switch machine and circuit controllers, splicing broken line wire, maintaining insulated joints and relocating and bonding track circuit feed wires.
The signal gang, typically 4 – 6 men, performs the heavier tasks including setting foundations and gate mechanisms, installing cantilever signals, renewing pole line or installing Electrocode, moving setting and wiring of signal cabins or bungalows and out-of-face direct burial and installation of signal cable runs.
The maintainers and signal gang(s) are supervised by a signal supervisor.
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Dealing with old man winter is a an expected activity for railroaders performing routine maintenance in the northern climes. Once the roadbed freezes up, maintenance work shifts from upgrading the track structure to coping with the demands of winter. In muddy track conditions, track must be shimmed as the mud heaves forcing rail up out of the plates. In extreme cold, rail and welds can become brittle. Changing out defective rails is a daunting task as the rail one worked so hard to raise the neutral temperature last year is now in a highly stressed tensile state. Pull-aparts from broken bars and sheared track bolts must all be repaired with minimal delay to trains.
Signal forces must deal with road salt interfering with the track resistance at crossings, thereby affecting crossing warning devices.
Out on the main track, gas fired or electric furnace switch heaters keep snow melted and clear of switch points so that electric switches throw reliably.
Subgrade failures from saturated fills like the photo (top left) can drop without warning, Track inspectors must be particularly vigilant for the signs indicating slope failure. Floods can inundate the track structure (photo top right). Water more than 6” above the top of the rail will ground out the locomotive traction motors. Washouts can occur anywhere along the track. Moving water will not be deterred. If adequate means is not available to handle the flow, water will make its own path.
Once the water goes down contractors, earth moving equipment and ballast and rip-rap trains are mobilized to attend to the damage.
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Maintenance of CWR
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Track buckles are not the result of an act of God. They result because of some outside influence providing a lateral or longitudinal load that the track structure does not have sufficient moment of inertia to resist. In very hot weather when the rail is in a highly compressed state, the rail may buckle. This is particularly likely if the track structure has been disturbed in combination with rail low neutral temperature and consolidation of the ballast section has not yet occurred. The buckle may happen immediately as occurred in this production tie gang or it may occur later underneath a train as in the bottom left photo. In tangent track, the buckle often takes the shape of an “S”. In a curve, the track frequently assumes a “C” shape.
Track buckles are preventable. Engineering out the potential for a sun-kink ahead or under a train in CWR is achieved through the adherence to specified procedures utilizing a combination of limiting speed restrictions applied for a given amount of tonnage and/or number of trains over a given time period until consolidation is achieved. The specifics to these procedures will vary according to the type of traffic, train consist, ambient temperature, physical characteristics of the railway and speeds operated. Each railway will have developed CWR policies and procedures pertinent to their operation. Procedures applicable to commuter/transit operations may not be applicable to unit train operations. However, it is essential that individual railway procedures be followed any time track disturbance occurs. Today, railways can quickly regain about 80% of the original track stability through the use of a dynamic track stabilizer.
Thus the goal when performing track work of any kind is to minimize disturbance. But when disturbance does occur, appropriate measures must be instituted until the track is again stable while still safely keeping train delays to the minimum possible.
To adjust CWR for a rail temperature higher than that which it was anchored, its length must be shortened so that compressive forces are converted to tensile forces. The rail is cut, anchors are removed and the amount to be shortened plus 1” for each weld is removed from the rail end. The rail ends are hydraulically pulled to together by 150 ton jacks (see slide) to close the gap and a thermit weld(s) are completed. The track is re-anchored and the rail segment is now at the new neutral temperature.
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Drainage & Vegetation Control
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The control of unwanted vegetation is another essential maintenance activity. Railroads typically apply a pre-emergent spray via hi-rail spray rigs in the early spring to the roadbed for most of the season control of grasses and broadleaves.
A post emergent late summer application of right-of-way beyond the roadbed is applied to control broadleaves and brush.
Mechanical cutting of vegetation can be broken down into localized mowing or chain saw removal of brush and tree species or the use of on-track based production cutting machines. Many of these machines are not suitable for use in urban areas because of the debris thrown and the splintered remains of the tree that is left behind. However, in more remote locations they are an effective means of clearing the ROW.
The three most important contributors to quality track are “drainage, drainage and more drainage”. The track ditch serves to carry away the water shed from the ballast section. Water trapped in the ballast section will soon lead to pumping track, fouled ballast and degraded track geometry and ultimately premature track component failure.
Specialized equipment such as the Jordan ditcher with extendable wings clear ditches of accumulated debris and vegetation hindering the free flow of water. These machines have the capability of creating the trapezoidal shaped ditch that is resistant to plugging up and will not undermine the toe of the ballast section slope. The desired end product is the ditch on the bottom left photo. Other specialty machines such as this rail bound grade-all and cranes equipped with clam-shell buckets are used to maintain ditches.
Roadbed exposed to ponding water are candidates for slope failure and/or muddy track conditions.
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Dealing with disasters of any kind is a prime component of the staff performing normal or routine maintenance.
These disasters can be a result of human failure beyond the railroad’s control such as this collision between Amtrak and a log truck or it could be the result of carelessness or a lack of attention to good train handling techniques.
Some disasters are a result of a mechanical failure such as a shifted load, dragging brake rigging, broken wheel or burned off journal, perhaps missing side bearings or a host of other related causes. The failure may be track induced such as a broken rail (the photo top right) or surface defect, or a result of a track buckle. The pile-up when it occurs can be awe inspiring. The damages to rolling stock and lading amounting to millions of dollars. Damages can even grow higher if hazardous materials are released.
Fire whether on the right-of-way or a bridge, which is often beyond the railroad’s control must be contained and the damages quickly alleviated.
Washouts, slope failures or floods also must be dealt with. The slide lower right shows a locomotive at the bottom of what once was a high fill. Notice the rail and few ties still attached swinging high over the unit.
Whatever the cause, the men and women making up the railway engineering department will spare no effort to return the line to service and to initiate actions that will prevent further occurrences of the same type.
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Next, let’s look at the programmed maintenance activities. These are typically capitalized.
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Purpose: Remove Surface Imperfections in the Rail & Optimize Rail/Wheel Contact Area
Out-of-Face & Switch Multiple Stone Grinders
Grinds Main Track Based on Railroad Policy
Grinds 6 to 15 MPH
October 2007
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Rail grinding is another maintenance activity that promotes increased rail life. Both the rail and the wheel have a radii at the contact point and when both are new results in the contact point being over the web of the rail. As rail wears the actual point of contact moves from the ideal location which causes increased rail and wheel wear. Rail grinding will re-establish the proper point of contact resulting in the correct L/V ratio and improved rail and wheel life.
Rail grinding is achieved through the use of specialized grinding machines or trains equipped with adjustable grinding wheels that can remove small amounts of metal at a very controlled rate in a series of passes. Depending on the amount of material to be removed and the number of stones utilized, grinding is typically performed at speeds ranging from 6-15 MPH. A typical switch grinder has 20 stones, while a production grinder commonly has 88 stones. Grinding is also used to remove surface imperfections in the rail such as checking and spalling on the low rail and corrugations on the rail head. Corrugations in transit properties produce the infamous roaring rail sound. In freight and commuter territory, it can eventually lead to detail rail fractures.
Rail grinding needs to be closely coordinated with weather conditions due to the potential for starting right-of-way fires. The grinders normally have a large water supply with them and wet the track area as they go however, in extremely dry conditions the potential for fires is very high.
2009 average daily cost for production rail grinding was $45,000.
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ALUMINOTHERMIC (THERMIT) WELDING (shorter life, local maintenance, etc.)
Thermit welding (top left) is a welding process, which produces coalescence of metals by heating them with superheated liquid metal from a chemical reaction between metal oxide and aluminum without the application of pressure. Filler metal is obtained from an exothermic reaction between iron oxide and aluminum. The temperature resulting from this reaction is approximately 2500° F. The superheated steel is contained in a crucible located immediately above the weld joint. The superheated steel runs into a mold, which is centered around the rail ends to be welded. Since it is almost twice as hot as the melting temperature of the base metal, melting occurs at the edges of the joint and alloys with the molten steel from the crucible. Normal heat losses cause the mass of molten metal to solidify, coalescence occurs, and the weld is completed.
FLASH BUTT WELDING (factory welds, high production, longer lasting)
Flash Butt Welding (top right) aligns the rail, charges rails electrically and hydraulically forges the ends together. The welder head automatically shears upset metal to within 1/8" of the rail profile. A base grinder removes the 1/8" flashing material from the rail, which leaves a smooth base and greatly reduces the likelihood of stress risers, which shorten the life of the rail. The sides and head of the rail are also ground to the profile of the parent rail. As a final step in the welding process, a mag particle test is performed. These quality checks, plus separate checks with a straightedge and taper gauge, contribute to the complete job that makes a quality weld. Thermite welding
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In all but the smallest crossings, the crossing track structure is often pre-paneled out adjacent to the crossing (top left) or at some other convenient location. The completed panels are then either off-loaded by crane or slid into place once excavation of the crossing is performed. Where adjacent ROW is available, completed panels several hundred feet in length can be installed if sufficient equipment is available. Pre-paneling helps minimize the disruption to the public and to rail traffic.
Prior to removal of the crossing surface material, the appropriate crossing permits must be secured from the local authorities, highway traffic detours arranged, a work window obtained from the railway’s Transportation Department and the appropriate detour signage and barricades placed.
Pneumatic or hydraulic impact tools are required to remove threaded lags in timber, rubber or concrete cast panel crossing materials. The existing track is then cut into convenient panel lengths, typically 39’, and lifted out by a crane – if tie condition is adequate to hold rail in place while the panel is lifted. With the trackbed exposed, excavation can begin. It is important that the graded surface be level and no more than 10” be removed below bottom of tie. At all costs, avoid excavating beyond the hardpan that has formed from years of consolidation from train traffic. The use of small tilt-blade dozers or comparable equipment is effective in holding a level grade. Other suitable pieces of equipment for removing and loading spoil from the immediate crossing site are also required. The crossing panels are either slid in or placed by a crane depending on the length and adjacent available ROW.
Once the panel ends are connected to the existing track, ballast is dumped either by ballast cars or via loaders. The track panels are then raised by the use of jacks to permit machine tamping and raising of the crossing to grade. Additional ballast is dumped and final surfacing and regulating is performed. Additional surfacing will often be required after train operation until all settlement is complete. The appropriate surface material is then applied.
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We now move to the activities beyond the scope of normal or routine maintenance.
This includes production work such as production surfacing, production relay of CWR, production tie insertion, and production undercutting. Each of these activities is designed to maximize productivity within the track windows present. The cost of these functions is beyond the capability of a supervisor’s normal budget and manpower consists. Extra gangs are created that often move from territory to territory even division to division performing specialized tasks. The accumulated experience obtained doing just one task makes these gangs very efficient and productive. These gangs are essentially rolling assembly lines that requires each segment to perform its task safely and efficiently to keep the entire process going.
The other engineering activity that occurs is the construction of new track for capacity improvements or to accommodate changing traffic patterns. The design engineering and construction project management for these activities are typically performed by consultants. In most cases, railways do not have sufficient staff personnel to devote to these additional activities.
If local labor agreements permit, railways may even contract out the construction of the trackage to outside contractors who are equipped to do such projects. Grading and roadbed construction are almost exclusively handled by contractors as most railways do not possess the equipment required to perform this work. Installation of the ballast section is usually done by the railway as the railway possesses the required ballast hoppers.
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The first production gang to be considered is the rail gang. Rail renewal is determined chiefly by the condition of the existing rail. Rail with significant secondary batter, chipped ends, bent joints, corrugations too deep to grind out or with excessive curve wear becomes impossible to maintain surface and speed restrictions have to be imposed. Rail segments that have had a history of recent failures, whether discovered ultrasonically or as outright broken rail are placed for special priority. Older jointed rail, within acceptable wear limits and that has been work-hardened by tonnage prior to the inception of 100-ton cars, is rail that can often be utilized for relay purposes. By cutting off 18" or more from each end, the bolt holes are eliminated and the rail can be welded into lengths of up to 1440 or 1600 foot long strings. This cascading effect generates a significant amount of the rail laid in North America – particularly on medium tonnage and secondary lines. Rail may be re-laid out-of-face for relay of existing rail or can involve the transposition of the high rail to the low rail and vice-versa in curves – a practice called transposing rail.
Rail gangs will typically range from 30 to 60 men in size with 10 to over 20 machines. As such, they are the most labor-intensive work function utilized. Expansion of the rail and installation at gage are the primary performance criteria that must be considered when laying jointed or continuous welded rail (CWR). CWR is laid at a Preferred Rail Laying Temperature (PRLT), which will be the rail's neutral temperature after anchoring and is designated per geographic location by the railway. The neutral temperature favors the higher range of expected rail temperatures, as a sun kink is typically more dangerous than a pull-apart. If necessary, the rail is artificially heated or cooled or adjusted hydraulically to a corresponding length in order that it is within an acceptable neutral temperature range. The rail is then anchored per railway standard in order to lock in the neutral temperature.
The entire work process starts with the unloading of the CWR which is welded at a rail plants and transported in special trains with strings usually around 1440’ long. Unloading the rail is a complicated and dangerous process that requires careful planning and preparation with close attention paid to turnouts, road crossings and bridge locations.
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Rail Gang Make-up
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Thread new rail to center of track - The first operation in the rail gang is the threading of the new rail from the shoulder into the center of the track ball up. Once the string is installed in the center of the track, the primary functions may begin.
Remove spikes - Automatic spike pullers pull most of the spikes with the remainder removed manually.
Remove anchors – The rail anchors are then removed either manually or by machine.
Thread old rail out - A rubber tired speed-swing or Galion Crane is used move the old rail from the tie plates out to the shoulder of the track.
Remove tie plates - Existing tie plates are removed. Depending on their condition or type they may be re-used or placed to the side for pick up as scrap.
Plug spike holes in ties - Spike holes in the ties are either manually filled with a wood plug or injected with an epoxy based filler compound.
Crib - A crawler based machine called a cribber sweeps the ballast out between the cribs with steel cable brushes to a depth that will permit machine installation of the new anchors.
Adze - A machine called an adzer then planes the top of the tie down to a smooth surface that will accept the new tie plate.
Replace tie plates - The next operation involves the setting of the tie plates into place with a pregager that provides a positive stop for the end of the plate
Thread new rail in - A speedswing or pettibone hi-rail equipped crane threads the new rail into place into the plates – the machine hi-rail wheels serving to seat and locate the rail.
Gage - This is followed by several automatic spikers, the first of which is equipped with an automatic gaging feature to ensure that the new rail is laid to gage based not on a ball to ball dimension (56-1/2”), but a base to base dimension that will ensure the rail will be to the proper gage once the first train properly seats the rail into the plates.
Heat - With completion of the gage spiking operation, the rail is heated with a diesel fuel or propane heater to a temperature slightly in excess of the desired neutral temperature. The rail has been pre-marked for the quarter, half and ¾ points on the string. The tie plate and rail base is match-marked at these locations. Once heating of the string begins, the required expansion is calculated and at each of these points the match-mark offset is compared against the calculated amounts to ensure that expansion is actually occurring.
Anchor - Immediately behind the rail heater, are a fleet of automatic anchor machines which apply the anchors to ensure that the expanded rail is locked into place. Should the rail temperature rise above the desired preferred rail laying temperature, the heater is shut off and the rail temperature becomes the new neutral temperature.
Spike - The automatic spikers are set up so that both inside and outside gage spikes can be driven simultaneously. It takes skill to rapidly locate the spike gun over the hole with the joystick controls. Once the hydraulic action is initiated, it can’t be stopped. A mislocated hole placement will result in a bent spike and potential gang delay down the line.
Pick up scrap and old rail – Burro cranes, specialized scrap retrievers, etc. are used to clean the right-of-way of the scrap material to ready the track for surfacing. This keeps the property clean, safe and the scrap metals are sold to help fund the projects.
Surface track - A ballast regulator fills in the ballast cribs followed by the surfacing gang and welders.
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Production Tie Renewal
6 to 20 machines
October 2007
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Tie renewal is typically scheduled ahead of rail relays to meet minimum FRA standards or to fit within cycle based programs. Tie life is a function of tonnage, topography and climate. For medium and light tonnage lines in a dry and relatively flat territory, a tie life of approximately 25 to 30 years is realistic except under joints or crossings. On heavy-haul – high tonnage lines, a tie life of 15 to 20 years is more realistic with wet climates and high curvature territories averaging closer to the 15 year life. Tie gangs will range from mini-gangs of 12 – 15 personnel to 30 to 35 men for high production units. Production may range from 500 ties per day installed for a mini-gang to an average of 2500 ties per day for a typical tie gang. Tie renewal is scheduled on a cycle basis with anywhere from 400 to 1500 ties per mile replaced out of approximately 3200 ties per mile. The intent is to keep all the ties from requiring replacement at one time – a staggering cash flow expenditure.
The typical tie gang is made up of two sections: the head end and the hind end. Sequence of operations will vary by railroad and differs somewhat for concrete tie installation, but in general follows accepted practices.
The first step is distributing the new material. The top picture shows a car topper unloading and spotting the ties to be inserted along the right of way.
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Tie Gang Make-up
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The next step in the process is pulling the spikes and spreading the anchors as shown in the top left picture. The TKO or tie inserting machines can remove the old ties from the track. (Bottom left). Each tie gang has several tie cranes that handle either old or new ties (top right). One tie crane may pile up the old ties out of the way to be picked up later while another crane will spot the new tie in the hole left by the old tie.
Once the ties have been spotted by the tie cranes, the inserter can shove them under the track in the hole left by the old tie. The plates are replaced between the new tie and the rail, and then the spikes are driven as shown in the bottom right photo and the anchors squeezed tight to the tie.
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Mechanized Tie Gang
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Surfacing refers to the operation, whereby the alignment and surface of the track are restored to within acceptable maintenance limits and the ballast is tamped underneath the ties. It can be classified as "spot" which is the localized repair to isolated locations often done through the use of jacks and ballast forks or shovels, or through the mechanized use of tampers, which is often referred to as smoothing. Production surfacing includes skin lifts, whereby low spots are corrected and the entire track structure is given a skin lift of under an inch to full out-of-face surfacing, whereby the track is raised 2 to 3" in a single pass, as would occur under undercutting operations or at road crossing renewals. Larger out-of-face lifts are ballast sensitive and sufficient ballast must be on hand.
It is interesting to note that in an article from the 1934 Roadmasters Maintenance of Way Association Annual Proceedings, William Shea, General Roadmaster of the Milwaukee, St. Paul & Pacific Railroad, bragged about his high speed surfacing and lining gang that could surface a mile per day. It consisted of 300 men tamping and raising the track, 100 men lining the track and 100 men following up two weeks later as a touch-up gang. Today with a foreman, 4 – 5 machine operators and possibly 2 laborer, 2-1/2 or more miles can be surfaced with a far greater degree of quality in the work performed. Indeed today, there are machines that combine all of the operations noted above in the typical surfacing gang into one machine, which can travel out to the work site at near train speeds.
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Surfacing Gang Consist
Dynamic Track Stabilizer
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Today's modern production tamper (CAT-09, continuous action tamper – machine does not stop but tamping head moves independently from tie to tie, MK IV – Harsco Company production/switch tamper), not only can tamp the ballast under the tie with vibrating tools that are inserted to either side of the tie and drop below the tie, where they perform a squeezing operation that compacts the ballast underneath, but are also equipped with jacks that can lift the rail vertically at the point of tamping. They also can move the rail horizontally for lining the track. Both vertical and horizontal jacking are controlled by projecting an infra-red light from a buggy set ahead of the machine (top left), which sends a light beam back to a receiver located at the rear of the machine.
Other machines included within the surfacing gang may include a tamper not equipped with jacks, that tamps every other tie behind the production tamper, thereby increasing hourly production rates. One or more ballast regulators (top right) are used to transfer or recover ballast where needed for tamping or filling the cribs and shoulders. The regulator is equipped with a power broom that sweeps excess ballast off the top of tie and provides that “completed” look. The surfacing gang may include a dynamic stabilizer (bottom left). This machine imparts vibrations of a given frequency into the rail to secure consolidation of the ballast structure. This restores lateral stability after the track disturbance created by surfacing and minimizes the placement of necessary slow orders.
Adequate ballast must be dumped ahead of the gang to ensure that cribs are not left empty and proper shoulders provided after surfacing.
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Undercutting, shoulder cleaning, sledding, plowing or track removal with open cut excavations is performed whenever the ballast section becomes so fouled with mud that line and surface can no longer be maintained, or overhead clearances are so tight that track raising is unacceptable. Undercutting production is generally limited by availability of ballast and the amount of hard packed mud present in the track. Typically, this will require 40 - 50 cars of ballast per mile of track assuming that 6” to 8" of ballast is removed from the bottom of the tie. The amount of ballast re-claimed will vary depending on the type of ballast in place and its condition. The dirt removed from the track is either wasted off on the ROW or loaded by conveyors into air dump cars. It is important that spoils wasted are bladed off so that a ridge trapping water is not created. A tie gang should be operated through the track segment prior to undercutting so that down-ties will be a minimum.
Undercutting operations also vary widely in set-up. However, the key component is the undercutter. This machine has a large chain with cutting teeth ( photo lower left) that is pivoted under the ties at the required depth to be undercut until the chain is perpendicular to the rail. As the chain rotates, the machine is moved forward. A large vertical rotating wheel equipped with buckets ( photo upper right) is mounted on the side of the machine. The buckets first create space at the end of the tie from which the chain can operate. The chain brings the material to the rotating buckets, whereby the ballast is carried upward and dumped onto vibrating screens (photo upper left). The dirt and smaller ballast fines drop through and are deposited onto a conveyor that wastes the material onto the ROW (photo upper right) or into an air dump car. The larger ballast is returned to the track.
Smaller, less productive undercutters are used for switch undercutting and even smaller units, called gophers, waste all material and are ideal for spot undercutting through bridges, platforms, etc.
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Authors: Joseph E. Riley, P.E. Federal Railroad Administration (202) 493-6357 [email protected]
Larry Romaine Rail America (904) 538-6054 [email protected]
Gray Chandler CSX (Retired) (904) 213-1121 [email protected]
October 2007
Romaine & Chandler
R. D. Kimicata
Art Charrow
J.G. Chandler
Charley Chamber
J.G. Chandler
Charley Chamber
J.G. Chandler
Mike McGinley
J.G. Chandler
5/16/2008ALLReverted format from PPTM to PPTR. D. Kimicata
1/28/201042Changed rail grinding picture and notesArt CharrowJ.G. Chandler
1/28/201045-47, 49, 50, 52change titles from "Team" to "Gang"Charley ChamberJ.G. Chandler
1/28/201050Added mechanized tie gang slideCharley ChamberJ.G. Chandler
1/30/201025Changed picture of Sperry carMike McGinleyJ.G. Chandler
7/25/201255Updated authors' informationJohn GreenN/A

12-track-inspection-&-maint-jan-10.ppt

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