1

ACKNOWLEDGEMENT

Research Design and Standard organization (RDSO), ManakNagar Lucknow is

one of the best R&D centres in India which is governed by Indian Railway. This

report is based on the Summer Training carried out at RDSO under the guidance

of highly dedicated Staff working under this esteemed organization. I take this

opportunity to thank Each and Every person who helped me and supported me

directly or indirectly in completing this training.

I would like to express our sincere gratitude to Mr. D. K. Srivastav (Testing

Directorate Head of RDSO) for providing administrative permission for my

summer training through which knowledge is explored beyond the class room

boundaries. I duly express my gratitude to Mr. S.K. Mishra (In-charge Training)

for his support and guidance throughout this training session.

I am very thankful to Mr. R.S. Kashyap for giving his reference for the

enrolment in Summer Training program in RDSO.

I am thankful to all the lab in-charge and superintendents and with whose

support and guidance the creation of report came to existence. Last, but not the

least my sincere gratitude to all persons who remained unexpressed in words.

Shivanshu Dixit

B-Tech(ME)

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ABSTRACT

This report is about the Non destructive testing of the various essential

components of the Railway at Testing Lab like Brake and Dynamometer Lab,

Measuring Wheel Lab, Air Brake lab and Fatigue Testing lab under Testing

Directorate of RDSO during the One month Summer Training.

This report include the essential machinery, workforce, vital parameters etc, for

Simulation and testing of the undertaken design for validation of all newly

designed/modified rolling stock developed, whether in house or imported. It

also includes the actual field and static trails for the components like Brake

Blocks, Engine and Bogie wheels, safety equipments- Air brakes, and fatigue

testing of the bogie frame and the components which undergo fatigue stresses

under the constrained environment of Labs and generating results for the tests

and Setting standards for the INDIAN RAILWAY.

3

Table of contents

1. Introduction…………………………………………....................................4

2. Testing Directorate……………………………..............................................6

3. Brake & Dynamometer Lab………………………………………………..7

3.1 Test Procedure and Allied Particulars………………………………….8

3.1.1 Physical Check

3.1.2. Bedding

3.1.3. Dry Test

3.1.4. Wet Test

3.1.5. Drag Test

3.1.6. Calculation of specific wear rate

3.1.7. Technical data and other observation

4. Measuring Wheel lab……………………………………………………..13

4.1. Prepartion of Measuring wheel & Instrumentation.. .… .……………14

5. Air Brake Lab……………………………………………………………..16

5.1. Types of Air Brake system …………………………………………..18

5.2. Working Principle……………………………………………………19

5.3 AB test rig system…………………………………………………….20

6. Fatigue Testing Lab

6.1. 100 ton measurement system………………………………………...23

6.2. 500 ton measurement system………………………………………...25

6.3 Stress Measurement…………………………………………………..29

7. Conclusion………………………………………………………………..31

8. References……………………………………………………………….32

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1. Introduction

INDIAN RAILWAYS, the premier transport organization of the country is the

largest rail network in Asia and the world’s second largest under one

management. Indian Railways owned and operated by the Government of India

through the Ministry of Railways. With the vast development in IR with the due

course of time such a big organization cannot run efficiently without adequate

R&D and design support. This is provided by RDSO at Lucknow.

Railways were introduced in India in 1853 and as their development progressed

through to the twentieth century, several companies managed and state owned

systems grew up. To enforce standardisation and co-ordination amongst various

railway systems, The Indian Railway Conference Association (IRCA) was

set up in 1903, followed by The Central Standards Office (CSO) in 1930, for

preparation of designs, standards and specifications. However, till

independence, most of the designs and manufacture of railway equipments was

entrusted to foreign consultants. With Independence and the resultant

phenomenal increase in country’s industrial and economic activity, which

increased the demand of rail transportation - a new organisation called Railway

Testing and Research Centre (RTRC) was setup in 1952 at Lucknow, for

testing and conducting applied research for development of railway rolling

stock, permanent way etc.

Central Standards Office (CSO) and the Railway Testing and Research Centre

(RTRC) were integrated into a single unit named Research Designs and

Standards Organisation (RDSO) in 1957, under Ministry of Railways at

Lucknow. The status of RDSO has been changed from an ‘Attached Office’ to

‘Zonal Railway’ since 2003. [1][2]

Organisation

RDSO is headed by a Director General. The Director General is assisted by

Additional Director General, Sr. Executive Directors and Executive Directors,

heading different directorates. RDSO has various directorates for smooth

functioning:

Bridges and Structures , Carriage , Defense Research , Electrical Loco , EMU &

Power supply , Engine Development , Finance & Accounts ,Geo-technical

Engineering ,Quality Assurance, Metallurgical & Chemical, Motive Power,

Psycho-technical , Research ,Signal , Telecommunication, Track, Testing, Track

Machines & monitoring, Traction Installation, Traffic, Wagon.

All the directorates of RDSO except Defense Research are located at Lucknow.

Cells for Railway Production Units and industries, which look after liaison,

inspection and development work, are located at Bangalore, Bharatpur, Bhopal,

5

Mumbai, Burnpur, Kolkata, Chittaranjan, Kapurthala, Jhansi, Chennai,

Sahibabad, Bhilai and New Delhi.

Quality Policy

To develop safe, modern and cost effective Railway technology complying with

Statutory and Regulatory requirements, through excellence in Research,

Designs and Standards and Continual improvements in Quality Management

System to cater to growing demand of passenger and freight traffic on the

railways.[3]

Functions

RDSO is the sole R&D organization of Indian Railways and functions as the

Technical advisor to Railway Board, Zonal Railways and Production Units and

performs the following important functions:

Development of new and improved designs.

Development, adoption, absorption of new technology for use on Indian

Railways.

Development of standards for materials and products specially needed by

Indian Railways.

Technical investigation, statutory clearances, testing and providing

consultancy services.

Inspection of critical and safety items of rolling stock, locomotives,

signalling & telecommunication equipment and track components.

RDSO’s multifarious activities have also attracted attention of railway and non-

railway organizations in India and abroad.

Infrastructure

RDSO has a number of laboratories which are well equipped with research and

testing facilities for development, testing and design evaluation of various

railway related equipments and materials. Some of these are:

Air Brake Laboratory is equipped with facilities for simulating operation

of air brakes on freight trains up to 132 wagons and 3 locomotives as also

for simulation of passenger trains up to 30 coaches.

Brake Dynamometer Laboratory has facilities to develop and test brake

friction materials for locomotives, coaches and wagons. A unique facility

in India, this laboratory has also been used by R&D organisations of

Ministry of Defence like DMRL, DRDL and HAL for indigenisation of

brake pads for defence aircraft.

6

Diesel Engine Development Laboratory has four test beds capable of

testing diesel engines from 100 to 6000 HP with fully computerized

systems for recording of over 128 test parameters at a time. This facility

has already enabled RDSO to develop technologies for improving fuel

efficiency, reliability and availability of diesel engines as well as to

extract higher output from existing diesel engines. Fatigue Testing

Laboratory for testing prototype locomotive and rolling stock bogies,

springs and other railway equipments subjected to stress and fatigue so as

to ascertain their expected life in service.

There are many more facilities in RDSO.

2. Testing Directorate

Testing Directorate of RDSO is one of the important directorates having field

units and testing labs. This Directorate undertakes design validation of all newly

designed/modified rolling stock developed, whether in house or imported.

Besides undertaking actual field and static trials, this Directorate has three

laboratories for conducting simulated trials on rolling stock sub-assemblies and

its various components.

In the year 1989 the present Testing directorate was created for carrying out all

dynamic and static mechanical testing activities of all type Railway Rolling

stocks. This directorate is looked after by Executive Director Research Testing.

The various tests and trials done by Testing Directorate can be broadly

classified into Field Trials and Laboratory Tests. Field Trials are those trials

which are conducted on newly designed prototypes and modified rolling stock,

for assessing ride quality and ride comfort apart from Route proving runs, Brake

trials and Coupler force trials to assess their behaviour in actual operating

conditions. Testing Directorate has also been entrusted with carrying out

periodic track monitoring runs on Rajdhani and Shatabdi routes.

Laboratory Tests are conducted on newly designed sub-assemblies and Rolling

Stocks components as well as quality audit check for assessing the suitability by

simulating service condition /field condition in three well equipped and

modernized laboratories.

Well-qualified, fully trained and vastly experienced dedicated team of 11

officers and 52 mechanical and instrumentation supervisors of the Directorate

are geared to meet the challenges posed in the field of testing of railway

vehicles and their components. [4][5]

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3. Brake & Dynamometer Lab

Following activities are done in Brake Dynamometer Lab

Mean and instantaneous coefficient of friction of brake blocks

Specific wear rate of brake block/pads

Maximum temperature attained by wheel and brake block/pads.

Variation of Coefficient of friction with change in environmental

conditions.

Emission of smoke and odour during dynamo testing in lab

A Brake Dynamometer Laboratory of RDSO has a dynamometer procured from

M/s MAN, Germany which was commissioned in 1974 and a new dynamometer

M/s Schenck Pegasus which was commissioned in 2005 for study of brake

material characteristics, development of new brake materials, study of braking

effect on wheels and quality control of brake block & disc brake pads. Salient

features of dynamometer equipment are as follows:

The new Brake Dynamometer housed in a hall measuring 28*10m. The actual

dynamometer measures 8.5*3.4*2.8m. The dynamometer machine is placed on

solid concrete floor. On this floor, the whole dynamometer rests on twenty nos.

( ten nos. on each side of dynamometer) of circular air cushions which act as

pneumatic vibration damper during the operation of machine.

The dynamometer is having two test stations thus allowing testing of one pair of

brake blocks at one work station and cooling of 2nd

work station at a time. The

dynamometer is also provided with the facility of testing of Disc brakes. The

dynamometer has facilities for simulation of maximum road speed of 300 km/h

with a one meter diameter wheel. An axle load up to 30ton & maximum brake

force of 6000kN per brake block can also be simulated. In addition to dry rail

condition, spraying water continuously on the wheel surface can also simulate

wet rail conditions.

For simulation of air impinging on the wheel, while the train is running,

ventilation system with fresh air volume range of 5200-15000m3/h for cooling

wheel and brake block and maximum 16500 m3/h of exhaust air for extracting

smoke, fumes and dust of the brake blocks out of the test stand exhaust is also

provided. The volume of fresh air can be selected as per requirement.

The control room is equipped with a Measuring cabinet consisting of Process

computer (VME) and has a control desk, which accommodates, control and

indicator switches and a data acquisition system .A dial meter displays the brake

cylinder pressure Rotation speed of wheel and braking time is digitally

8

displayed. A PC has been provided for operator for loading the test programs

and as a user interface for dynamometer control and monitoring during the test.

The data of various brake characteristics e.g. speed, braking time, run out

revolution, brake torque, brake horse power, brake energy are recorded by the

data acquisition system (VEM) (DAS). The temperature of the Brake Block is

also recorded in the DAS with the help of thermocouples and Pyrometer, and

the temperature of the wheel is digitally displayed separately. The value of

mean coefficient of friction for individual brake applications is also recorded in

DAS. A graph of instantaneous μ versus speed is also drawn for each brake

application.

a. b.

Figure .1 a. Brake block Label for Testing*; b. Disk brake for Testing*

a. b.

Figure .2 a. MAN’s Dynamometer*; b. Schenck Pegasus’s Dynamometer*

3.1 Test Procedure and Allied Particulars

3.1.1. Physical Check:

After the receipt of the brake block samples in the laboratory, these are

registered and identification numbers are stamped on each brake block. These

9

brake blocks are physically checked to ensure that they match the wheel profile

of the rolling stock for which testing is to be done.

3.1.2. Bedding:

The brake blocks are then fitted on the dynamometer for bedding to achieve

about 80% of the block contact area .This exercise is necessary to have a

uniform distribution of brake block force over the full brake block area during

the tests. Bedding of the brake block is done at a speed of 60km/hr and with a

brake block force of 2000kg .During bedding a wheel temperature up to 80-

1000c is maintained.

After the contact area of the brake block is needed to about 80%, tests are

started as per test scheme.

3.1.3. Dry Tests:

Brake block are tested under dry condition at speeds of 40, 60,

80,100,110,120, 140 & 160 km/h with a brake block force of 3400kg and

at speed of 40, 60, 80 & 100 km/h with a brake block force of 4940kg.

Three applications are made at each speed and the initial wheel tread

temperature, as far as possible, is maintained b/w 70 and 1000c. During

test, the volume of fresh air provided by the blower of ventilation system

is kept as 5200 m3/h.

Various parameters e.g. braking speed, braking time, run out revolution,

brake energy, brake pressure, brake torque, temperature and

instantaneous and mean coefficient of friction are recorded on the data

acquisition system.

Ni-Fe/Ni type-K thermocouples are embedded on the brake blocks to

monitor the brake block temperature.

Wheel temperature is measured with Pyrometer, however, measured with

a highly sensitive contact less sensor INFRA radiation sensor mounted at

the wheel rim very close to the rubbing surface. This temperature is

digitally displayed.

At the end of the each test series, the brake blocks are inspected in respect

of grooving, metallic inclusion, burning, non-uniform wear, over heating

etc. and surface condition of wheel tyre in respect of polishing, pitting,

flaking, cracking and other defects.

Brake blocks are weighed for wear as per test schemes.

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3.1.4. Wet Tests:

As laid down in the specification, continuous flow of water at the rate of

14 l/h is allowed to fall on the top of the wheel through small nozzles of

1-mm dia during wet tests. It simulates the rainy season conditions.

During wet tests, blower is not used. This is to avoid flying away of water

falling on the top of the wheel.

Acceleration, running and braking at desired force are done in the same

manner as the dry tests.

During the wet tests, also inspection of both wheel and brake blocks is

done for any abnormally as of dry test.

3.1.5. Drag Tests:

After dry and wet tests on the brake blocks are over, the samples are

subjected to most severe type of braking, simulating controlling of train

on ghat section by applications of continuous brake.

The brakes are kept applied on the wheel for 20 minutes without

switching off the motor at a constant speed of 60 km/h. During drag tests,

torque equivalent to about 45 BHP is maintained. For maintaining of

constant torque, the brake force on the brake block is recorded at every 60

sec. At the end of 20 minutes maximum temperature attained by the

wheel and brake blocks are recorded. In case of brake blocks catching fire

or any abnormality observed in course of testing, further drag testing is

stopped.

Immediately after drag test brake block force is increased to 2400 Kg and

brakes are applied and various brake parameters are recorded.

A wheel having a dia of 1092mm was used for these tests. Tests were

carried out on Flywheel Mass test stand as per test scheme. Flywheel

masses having a moment of inertia of 3130 kgm2 including that of

revolving wheel and stub axle were engaged to simulate an axle load of

21.0 ton.

During drag tests phenomena like, emission of smoke and spark,

formation of red band and flaming etc. are recorded. At the end of the

test, inspection of the wheel and brake block is done to see any

abnormality on the wheel and brake blocks.

Since the test program starts acquisition of data for mean coefficient of

friction after development of 95% brake power in the brake cylinder.

Calculations are done as suggested in RDSO specifications.

11

Figure .3 Graph Coefficient of friction vs. speed

3.1.6. Calculation of specific wear rate

From the table given below the specific wear rate value under dry & wet

condition is 2.06cc/kwh for brake block sample against the RDSO specified

limit of 4cc/kwh.

Specific wear rate= W*1000000 cc/kwh

D*E*2.72

Where, W= Total wear of the Brake Block in gm

D= Density of the brake shoe material gm/cc

E= Total energy dissipated during a particular series of test in kgfm

Sample

no.

Condition E(kgfm) W(gm) Density D

gm/cc

Specific wear

rate- cc/kwh

1 Dry 6619388 94.5 2.64 2.06

Wet (with

3400kg brake

force only)

Table .1. Specific wear rate of brake block under different condition.

3.1.7. Technical data and other observation

Other observation:

No metallic inclusion was observed during the bedding as well as during

testing of the sample.

No grooving, burning and overheating was observed from the brake block

during the tests.

The wheel tyre was having no pitting marks, no flaking, no cracking

during test.

12

The normal light smell and smoke, as is prevalent in the entire

composition brake block, was experienced during the test particularly at

140 & 160 km/h speed.

Figure .4 Technical Data

Figure .5 Testing Condition on Schenck Dynamometer*

13

4. Measuring Wheel lab

In measuring wheel lab Railway wheel (latest are LBH wheel) (Locomotive-

1092mm, Wagon-1000mm, coches-915mm) is prepared for simulation for

vertical and lateral forces. These are done on the Calibration Test Rig in which

Load application is done for Static and Dynamic condition for testing the

measuring Wheel. The test bench is hydraulic Pressurised for lateral and

horizontal force for simulating the actual working condition of the wheel.

Figure .6 Hydraulic testing rig for measuring wheel

Transducers are used for measuring the forces. Different types of transducers

which are used for measuring different type of force, some of them are:

Lateral transducers

Vertical transducers

Position transducers

While measuring prepare wheel by attaching transducers and making wheat

stone bridge arrangement depending upon the calculation that how many bridges

for lateral, vertical or for position.

Now, when load is applied the deflection measured by bridges in the form of

millivolts. The wheel is prepared by attaching wheat stone bridge all around the

wheel and its testing is done.

Results are generated via data acquisition system and interpolated for the mean

value.

Measuring wheel lab consists of following equipments:

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Power Pack which consists of stepper motor

A solenoid valve to vary hydraulic pressure

Testing rig

Load cells

Jib crane

DAS and other electronic sensors

4.1. Preparation of Measuring wheel & Instrumentation

The instrumentation is done as per test scheme. Normally,

instrumentation used for recording data is transducers as input device,

signal conditioners as processing device and chart recorders and/or

computerised data acquisition system as output device. Power supply unit

is used to provide power supply to signal conditioners and recorders and

excitation to passive transducers.

Transducers are used to measure acceleration, deflection and force.

Signal picked up from transducer is fed into signal conditioner for

processing. The processed output from signal conditioner can be recorded

on chart recorder and/or acquired on computer (PC or laptop) through

data acquisition cards.

Transducers normally used are passive types either resistive or inductive.

Transducer used for measurement of acceleration in x, y and z directions

is also called accelerometer and can be either, ‘strain gauge type’ or

‘piezo electric’. Transducer used for measurement of deflection of spring,

bolster, bogie movement etc can be either LVDT, i.e., linear voltage

differential transformer or string-pot. Transducer used for measurement

of force or load at axle box level is normally a load-cell. Measuring wheel

measures lateral and vertical forces at rail wheel level. Transducers are

excited either by 5V rms 2.5 kHz AC or DC voltage to provide output

signal.

Load cell assembly is used for recording lateral forces at axle box level.

Load cell of strut type is manufactured in-house suiting to the axle box

arrangement with range of measurement from 0 to 10t compressive load

only. Load cell is of full bridge resistance type and calibrated with

excitation voltage from 5 to 10V AC and under pre-calibrated hydraulic

jack. Its output is about 90 mV/V/tonnes. A load cell calibration chart is

prepared with load in tonnes on x-axis and mV output on y-axis. The

excitation voltage used during calibration is mentioned in the chart. Care

should be taken to use the same excitation voltage during trial.

15

Measuring wheel is used for measuring vertical and lateral forces at rail

wheel level. FEM analysis of wheel conforming to s-shape web profile is

carried out to determine the strain gage locations sensitive to vertical and

lateral force. The strain gage locations used for measurement of lateral

force are having minimal effect of vertical wheel load and similarly,

strain gages for vertical wheel load are having minimal influence of

lateral load. The cross talk between vertical and lateral forces is kept to

the barest minimum while selecting the locations.

Wheatstone bridges are formed for vertical and lateral force measurement

channels. Measuring wheel supplied by Swede Rail has two vertical and

one lateral load sensing bridges per wheel. Sixteen strain gage locations

have been selected for vertical bridge with two gages per arm and twelve

locations for lateral bridge with three gages per arm. This means that in

one revolution of the wheel two vertical and one lateral value would be

obtained. Measuring wheel supplied by AAR has one position channel in

addition to above, which indicates the rail wheel contact point.

Output of channels is taken from slip-ring device fitted on axle end cap.

AAR measuring wheel-set has slip-ring device on both ends of the axle.

Swede Rail measuring wheel-set has slip-ring device on one end of the

axle. Output signal lead from left wheel to right wheel is transferred

through a hole drilled in the axle. This has been done to save the cost of

slip-ring device.

a. b.

Figure .7 a. Power Pack assembly ; b. Operator preparing wheel

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5. Air Brake Lab The brake system it should have the following basic requirements:

Should be automatic and continuous i.e., at the event of train parting

brake should apply.

Shortest possible emergency braking distance.

Maximum possible brake force.

Shortest brake application time.

Shortest brake release time.

Low exhaustibility of brake power under continuous or repeated brake

application.

Minimum run-in and snatch action during braking

Types of brake system [6]

Vacuum brake

Single or Twin pipe graduated Air brake system

Electro-Pneumatic brake

Advantages of Air Brake System

It has higher rate of propagation.

It has shorter brake application and release time.

Brake fade does not take place, therefore, the train can be held on down

grade without any difficulty for a considerably longer period.

It has higher degree of reliability, controllability and maintainability.

Rigging is simple and entire equipments are lighter and required less

space.

Simple maintenance through calling for a higher degree of skill

Provide for higher operating speed.

Caters for smaller emergency braking distance.

Compressed air can be stored to higher-pressure differential.

Advantages of Electro-Pneumatic brake

Electric assistance is taken to control the B.P. Pressure with the help of

E2NV valve and core 9 cables.

E.P. valves are energized either for application or Release by a train line

circuit.

E.P. brakes are such designed that in case of failure, Air brake can be

applied to perform braking operation.

17

The laboratory is equipped with a Test Rig having the complete pneumatic

circuits of 132 wagons and 30 coaches with twin pipe air brake system. Three

locomotive control stands can be used anywhere in the formation, with varying

compressed airflow rate up to 16 kilo litres per minute with the help of 7

compressors. Data acquisition and analysis is completely computerised. The

laboratory is equipped with a single car test rig and an endurance test rig for

distributor valves. Brakes are essentially meant for controlling the speed and

stopping of train.

Following activities are done in Air Brake Lab

Effects of changes in design of loco brake system on brake characteristics

of passenger & freight trains

Brake characteristics of freight & passenger trains with multiple loco

operation

Optimum location of locos in long freight train

Effect of changes in design of distributor valve on brake characteristics of

freight & passenger trains

Brake characteristics in case of train parting alarm chain pulling and

guard van application

Effects of leakage rates on release of brakes

Effects of over charge feature on train operation

Indication to driver in case of train parting

Performance and endurance testing of distributor valve

Performance testing of compressor of locomotive, EMU and DEMU

Performance testing of MERVCD

Calibration of pressure gauges, pressure transducers pressure recorder

and other pressure Measuring instruments of brake lab and other units &

labs of testing directorate and other directorates of RDSO.

Performance testing of EGTT (End on Train Telemetry system) on 38 &

116 Boxn wagon freight train.

Performance of APM (Automatic pressure regulating device) of Bogie

pressure regulating device of bogie mounting brake system.

Performance of ABU (Automatic Brake Unit) of anti-collision device in

26 coaches and 58 boxn wagon train.

Air Brake System

Single pipe graduated release air brake system is used in air braked wagons. The

main components of this system are :

Brake application stand

Distributor valve

Brake Cylinder

18

Auxiliary reservoir

Control reservoir

Brake pipe and feed pipe

Flexible House Coupling

Rubber House pipe

Brake pipe which runs throughout the length of the train has air pressure at 5

kg/sq.cm. The compressed air is supplied by compressor /expresser in the

locomotive and the brake pipes of adjacent wagons are joined by using flexible

coupling. For application of brakes, the air pressure is reduced. The drop in

pressure being proportional to the braking effort required. The drop in pressure

is sensed by the distributor valve (DV) which allows compressed air from the

auxiliary reservoir into the brake cylinder and results in brake application

through brake shoes, release of brake taking place by normalizing by A-9and air

from the brake cylinder released simultaneously brake pipe pressure increased

up to 5 kg. The brake cylinder develops a maximum air pressure of

3.8kg/sq.cm.

During application of brakes the auxiliary reservoir gets disconnected from the

brake pipe. The auxiliary reservoir has capacity of 100 litres capacity whereas

control reservoir is of 6 litres capacity.

Figure .8 Twin pipe gradual release air brake system

5.1 Types of Air Brake System

Direct Release Air Brake System – AAR Standard[7]

In direct release air brake system, the release of brakes depends upon complete

build up of BP pressure. Since the pressure differential between brake pipe and

19

the Auxiliary reservoir controls the both application and release, the release

pressure once initiated cannot be stopped except by reduction in brake pipe

pressure below AR pressure, which if resorted to frequently before the

Auxiliary Reservoir is charged fully, will results in the exhaustibility of the

brake system.

The main advantage of direct releaser system is that it has faster release

compared with the graduated release system. The addition of emergency valve

to the triple valve in the direct release system permits, a very rapid application

by venting the train pipe locally at every vehicle.

Graduated Release Air Brake System – UIC Standard[8]

In graduated release system, the Brake cylinder pressure varies according to

brake pipe pressure. The brakes are fully released when the BP pressure is fully

charged. The graduated release system is inexhaustible as the BC pressure is

related all times to the pressure in brake pipe, full release of the brakes being

obtained when brake pipe have been fully charged.

The main advantage of Graduated release system is quick release of brake

system and reduced release time. The graduated release brakes are considered

more suitable for passenger stock because of inherent smooth release function

promoting riding comfort.

The graduated release system conforms to UIC regulation, which lays down a

release time of 45-60 seconds. In the graduated release system the application of

the brake can be accelerated with brake accelerator valves which can be

attached to the main control valve.

5.2 Working Principle of Air Brake System[9]

In air brake system compressed air is used for operating the brake system. The

locomotive compressor charges the Feed pipe and Brake pipe throughout the

length of the train. The feed pipe is connected to the Auxiliary reservoir and the

brake pipe is connected to the distributor valve. AR is also connected to the BC

through DV. The brake application takes place by dropping the air pressure in

the brake pipe by the driver from locomotive by the application of A-9 valve.

Following three activities involved in this system:

Charging

Brake pipe throughout the length of the train is charged with the

compressed air at 5 kg/cm2.

20

Feed pipe throughout the length of the train is charged with compressed

air at 6 kg/cm2.

Control reservoir is charged to 5 kg/cm2.

Auxiliary reservoir is charged to 6 kg/cm2

in case of twin pipe and 5

kg/cm2 in case of single pipe.

Brake Application

For brake application, the brake pipe pressure is dropped by venting air from

driver’s brake valve subsequently the following action takes place:

The control reservoir is disconnected from the brake pipe.

The DV connects the AR to the brake cylinder and the brake cylinder

piston is pushed outwards for application of brakes

The AR is towards continuously charged from the feed pipe at 6 Kg/cm2

air pressure.

Brake Release Stage

Brakes are released by recharging brake pipe to 5 Kg/cm2 through the

driver’s A-9 brake valve.

The DV isolate the BC from AR.

The BC pressure is vented to atmosphere through DV and the BC piston

moves inwards.

Emergency Brake Stage

D-1Emerency valve under the driver’s seat to drop the BP pressure and

brakes are automatically applied.

S.No. Description BP pressure BC pressure

1. Release/ charging 5 kg/cm2 0 kg/cm

2

2. Minimum Reduction 4.4-4.5 kg/cm2 0.8 kg/cm

2

3. Full service 3.2 kg/cm2 1.8 kg/cm

2

4. Over Reduction 2.5 kg/cm2 1.8 kg/cm

2

5. Emergency 0 kg/cm2 1.8 kg/cm

2

Table.2. Braking pressure at various position for coaches.

5.3 Air Brake System Test Rig

Air brake test rig is, with a facility for simulation of field condition for 132

wagon freight train & 30 coach passenger train with single and twin pipe air

brake system with data acquisition facility on 234 channels only. This test rig

has also facility to acquire data of BP, BC at every wagons on 58 wagons

freight train and for 30 coaches passenger train with BP, FP, BC, & MR on

three locomotive along with facility to measure air flow at four points on whole

21

test rig. The test rig is designed to measure real time pressure in brake pipe,

Feed pipe, brake cylinders in coaches and wagons and BP,FP,BC,MR, and air

flow in three multiple locomotives on 234 channels data acquisition system with

a sampling rate of 100 sample per second during initial charging of brake

system and application and release of brakes.

The application software is in LABVIEW and Data Acquisition system is also

of National Instrument. The software is such that it can calculate the application

and release time of any intermediate coach/wagon with the help of 0.08%

accuracy (very high accuracy) GE Druck /Germany make pressure transmitters.

The exact flow of air is cross checked by flow meter connected in BP and MR

line. It can check the application and release time with flexible number of

coach/wagon connected with loco within the maximum limit.

a. b.

Figure .9 a. Air brake test rig*; b. EP assist brake test rig*

Test Perform

This test rig is being used to test the performance of brake valves and

equipments on the simulated train consist in stable condition to study on under

mentioned scopes.

Braking characteristics of freight train up to 132 BOXN wagon with

single and twin pipe system.

Passenger train up to 30 coaches with twin pipe system.

Effect of change in design of loco brake system on braking characteristics

of passenger and freight train.

Brake characteristics of freight and passenger train with multiple loco

operations.

Optimum location of locos in long freight train.

Effect of changes in design of distributor valve on brake characteristic of

freight & passenger train.

22

Brake characteristic in case of train parting.

Effect of leakage rate on brake system.

Effect of over charge feature on train operation.

Optimum compressor & reservoir capacity for various train lengths.

Indication to driver in case of train parting.

Performance test of distributor valves.

Performance test of all valves and equipments of loco, coaches and

freight brake system.

Effect of EOTT on train brake operation.

Effect of Automatic Brake Unit of Anti-Collision device of locomotive

on Brake operation.

Figure .10 Schematic diagram of single pipe air brake system

Figure.11. Block diagram of twin pipe air brake system

23

6. Fatigue Testing Lab

Railway components undergo large fatigue stress because of extreme working

conditions and loading. Newly designed bogie frames are subjected to stress

investigation and Fatigue Test. The object of these tests is to determine stress

levels, both in nature and magnitude, at different critical locations on the bogie

frame, by simulating static and dynamic loads likely to be experienced by the

bogie frame under actual service conditions. Also, the adequacy of the design of

the bogie frame, from structural strength point of view is determined by

applying dynamic load up to 6 or 10 million cycles, as the case may be, for

conducting fatigue tests and monitoring the stresses at different critical

locations.[10]

Both the wagon and coaches bogie frames are tested for higher numbers of

cycles which is calculated by Fatigue theory for better use of the components

and prevents its failure.

Following activities are done in Fatigue Testing Lab

Structural strength test of new designs of structures like Bogie frames,

Bolster, Brake Beam of railway rolling stock to check their design

adequacy by simulating different service and exceptional load.

Fatigue test of different components such as FRP sleepers , Rail Joints,

Shock Absorbers etc. by simulating service loads

Fatigue and load deflection test of different metal bonded rubber

components such as Elastomeric pads for Casnub Bogie of wagons ,

Rubber Buffer Springs, PU Side Bearer pads, Loco Side Bearer pads, PU

Side Bearer pads, Constant Contact Side bearer Pads by simulating

service loads.

6.1. 100 Ton Capacity Fatigue Testing System

To conduct general fatigue test on full scale structures a closed loop electro-

hydraulic servo controlled fatigue testing system of 44 tone capacity with

facility of testing full size structures simulated service condition was installed in

the fatigue lab of RDSO in year 1972. This system was procured from

MTS/USA. Then because of the capacity and design constraint a new 100 tone

capacity fatigue system was procured from M/s Instorn U.K. and installed in

fatigue lab in 1997.

Salient Feature of the system:

The test system basically consists of closed loop electro-hydraulic computerized

fatigue testing equipment. It is provided with two hydraulic power supplies for

generating high hydraulic pressure required for producing the desire forces. The

24

high pressure hydraulic fluid at 210 kg/cm2 is fed to the hydraulic actuator to the

maximum rate of 500 LPM, through a servo-value. The actuator, which is a

cylinder piston arrangement, applies the compressive/tensile forces to the

specimen mounted on the test bed. The desired level of loading is achieved by

the controller in computerized control equipment of the system. A command

signal is fed to the input module which passes it on to a servo controller. The

desired dynamic wave form is provided by a function generator. The controller

sends electronic signal to the servo valve to regulate its port opening in such a

manner as to achieve the desired load level. A feedback transducer introduced

in the system, sense the load applied to the specimen and sends a proportional

signal to the input module. Here, the feedback is compared with the command

and any difference in their magnitudes or polarity is corrected through an

electronic signal to the controller. With this arrangement any continuously

varying command is reproduced faith fully.

The desire load is achieved through under mentioned set of dynamic actuators,

one 50 tone and three 35 tone capacity reaction frames mounted on rail type

slotted bed of 7.5m*14m size.

Figure.12. 100 tones fatigue testing machine with actuators*

Capabilities of system:

System can provide dynamic and static loadings on two axes simultaneously up

to a maximum load of 100 tonnes in combination of above mentioned actuators.

25

System has facility to provide sine, square, haver-sine and triangle waveforms

of loading in dynamic mode.

Benefits:

Rolling stock components like bogie frame and bolster of Box- N wagons,

Coaches and locomotives, Side bearer pads, friction snubbers, brake beams,

buffer springs, elastomeric pads, upper and lower spring pads, bridge stringers

Composite material sleepers etc. are regularly being tested on this machine.

S.No. Type of

actuator

Quantity Capacity Stroke Frequency w.r.t.

Displacement

Remark

Displacement

in mm

Frequency

in Hz

1.

Dynamic

Actuator

4 25 tones +-

50mm

2.5 10 Actuators can

work in tensile

& compressive

Mode 50 0.3

2.

Dynamic

Actuator

2 10 tones +-

50mm

2 10 Actuators can

work in tensile

& compressive

Mode 50 0.5

Table.3.Specification of 100 tones Fatigue Testing Machine.

6.2. 500 Tones Capacity Structural

Before Sep-2010, Fatigue testing lab of Testing Directorate was equipped with

100 tones capacity fatigue testing system with a maximum of 25 tones load

actuators. This system was capable to cater the general fatigue testing

requirements of bogie frame and bolster of existing wagon with maximum axle

load of 22.82 tones. Towards the process of development of high axle load

wagons, RDSO now is in process to develop the higher axle load wagons as per

the AAR standards. The bogies and bolsters of higher axle load wagons are

supposed to clear the accelerated fatigue testing on 453 tones static and dynamic

loadings as per the AAR test criteria. Hence this system has been procured to

cater the future testing requirements for higher axle load wagons as per the

AAR testing parameters.

Salient Feature of the system:

This system is very high capacity equipment which can test the specimen up to

a load of 500 tones in static and dynamic modes. But it has been designed in

such a way that this huge system can be utilized for testing of smallest

26

components of rolling stock under 0.5 tones also, for its optimum utilization.

The system is equipped with two hydraulic power units with six pumps of 100

LPM in each HPU to generate 3000 PSI hydraulic pressure on 1200 LPM

discharge rate to achieve the desire load through under mentioned set of

dynamic and static actuators and 500 tone capacity reaction frame on 10*10

meter ‘T’ slotted bed plate, which can bear 600tones load.

The test system basically consists of closed loop electro-hydraulic computerized

fatigue testing equipment. It is provided with a hydraulic power supply for

generating high hydraulic pressure required for producing the desired forces.

The high pressure hydraulic fluid at 3000 PSI is fed to the hydraulic actuator

through a servo-value. The actuator, which is a cylinder piston arrangement,

applies the compressive/tensile forces to the specimen mounted on the test bed.

The desired level of loading is achieved by the controller in computerized

control equipment of the system. A command signal is fed to the input module

which passes it on to a servo controller. The desired dynamic wave form is

provided by a function generator. The controller sends electronic signal to the

servo valve to regulate its port opening in such a manner as to achieve the

desired load level. A feedback transducer introduced in the system, sense the

load applied to the specimen and sends a proportional signal to the input

module. Here, the feedback is compared with the command and any difference

in their magnitudes or polarity is corrected through an electronic signal to the

controller. With this arrangement any continuously varying command is

reproduced faithfully.

Figure.13. 500 tones fatigue testing machine with actuators*

27

S.No. Type of

actuator

Quantity Capacity Stroke Frequency w.r.t.

Displacement

Remark

Displacement

in mm

Frequency

in Hz

1.

Dynamic

Actuator

2 125

tones

+-

125mm

3 20 Actuators can

work in

compressive as

well as in

tensile mode

also

225 0.15

2.

Dynamic

Actuator

2 25 tones +-

125mm

4 20 Actuators

can work in

compressive

as well as in

tensile mode

also

250 0.25

3. Static

Actuator 4 75 tones 300mm Not applicable

Actuators

works in

compressive

mode only Table.4.Specification of 500 tones Fatigue Testing Machine.

The other important features are as under:

Automotive test controller for controlling 8 actuators upgradable up to 32

actuators.

96 channel data acquisition system for on line stress recording.

T-slot bed plate of 10m*10m size which can bear dynamic load of 500

tones.

Four column portal frame of 500 tones capacity.

6-point concentrator of 600 tones capacity and 3 point force concentrator

for combined load application of multiple actuators.

Manual movement of ram of actuators through pendant.

Hydrostatic bearings have been provided in all the actuators to bear

maximum angular thrust.

Height of transverse beam can be adjusted through motorized lifting

device with laser beam safety monitoring system.

Heavy duty spring loaded roller clamp for easy sliding of cross beam and

actuators.

Following features make’s this system different form the 100 tone Instron

make old fatigue testing system

28

This system can test the specimen up to 500 tones static and dynamic

load whereas old Instron machine is capable to test up to 100 tones only.

2. A wide range of testing can be accomplished on these heavy load

actuators with +-125mm stroke whereas max. stroke of Instron make

actuators are +-50mm.

Automotive test controller for controlling 8 actuators with smart wave

software capable of sequential loading between two to all eight actuators

on different load, different frequency and different phase.

Facility to provide different waveforms of loading: sine, square, ramp,

rounded ramp, haver-sine and triangle.

Facility to provide vertical loading, lateral loading and longitudinal

loading simultaneously in different phase, frequency and amplitude.

System can run in automatic mode on pre-programmed loading test

scheme.

96 channel data acquisition system for on line stress recording with auto

channel balancing and auto calibration.

Facility of simultaneous acquisition and real time display of feedback

channels (position & load) of actuators with stress value.

System to measure deflection up to 1 inch with accuracy of 0.001 inch.

Continuous running of the machine with feedback system through SMS

in case of any breakdown in the machine. This facility will reduce testing

time and manpower in other than general shifts.

Capabilities:

1. This system can test the specimen upto 500 tones static and dynamic loads.

2. Future heavy axle load wagons bogie, bolster and other components can be

tested as per AAR standards.

3. Load deflection test and energy characteristics test can be done on helical

springs and rubber buffer springs through the machine, since stroke of the

actuators are 250mm.

4. Calibration of CBC can be done in tensile and compression mode at 150

tones.

5. With the help of 96 channel data acquisition system on line stress recording

with auto channel balancing and auto calibration which shows directly stress

value. This reduces the testing time and analysis time of data.

6. T-slot bed plate provides lot of flexibility while mounting the test sample

under the actuators.

7. Two hydraulic power supply units each provided with six pumps with

automatic flow control to save the power i.e. No of motors in use will automatic

are selected by the system depending upon the oil flow requirement.

29

Benefits:

Accelerated Fatigue Testing of Bogies & Bolster of high axle load wagons as

per AAR specifications. This Fatigue Testing Machine will help for design

validation of high axle load wagons i.e. 25t wagon & 32.5t etc. & other rolling

stocks (coach & locos) also by simulating field load conditions. This will also

help to improve the reliability of wagon bogie, bolster and other structure by

assessing the fatigue life of sub assembly.

6.3. Stress Measurements

The bogie is strain gauged at locations specified in the test scheme, which are

mostly linear gauges and a few three-directional Rossette gauges. Each gauge

(the arm in the case of Rossette gauges) fixed on the bogies frame, functions as

an active arm of Wheatstone bridge for monitoring the strain / stress. The

remaining three gauges required to form the Wheatstone bridge, called the

dummy gauges, are cemented on steel strips mounted on a junction box, kept

close to the bogie frame during the course of the tests. Terminals of the bridge,

thus formed, are connected to the recorder (visicorder).

During the stress recording in static condition, the bogie is subjected to the

desired load combinations and three sets of readings are taken for every load

combination. It is generally noticed that the difference between the three

readings is practically negligible. Before conducting the dynamic stress

measurement, the bogie frame is subjected to the desired load combinations for

at least for 3 to 5 minutes and thereafter, the readings are taken.

Fatigue Test

The bogie frame is subjected to fatigue test by applying dynamic load

combinations as per test scheme. The load application is of sinusoidal nature,

which is achieved with the help of the function generator available with control

panel of the fatigue testing equipment. Fatigue tests are carried out upto 10

million cycles. The test frequency, with the stabilised test set up, is achieved as

3 to 4 Hz. All the dynamic load actuators are applying load at the same

frequency and in the same phase.

Vertical Load Application & Reaction

The bogie frame is placed on the four vertical stools clamped with the test bed.

The loading is done with the help of load actuators, each with the capacity of

+10 or 25 t mounted on the two separate main reaction frames capable of

bearing 30 or 50 t force and located longitudinally on both the sides of test bed,

30

through two loading beams placed at the ends of bolster which, in fact, is kept

on two specially designed steel tubes (in place of secondary springs) placed in

the spring seat guide located in the middle of the side frames.

Reaction of the vertical load at axle box location is attained through fabricated

steel tubes placed between the bogie frame and vertical stool at all the four

locations. Specially designed load cells, one each at all the four axle box

locations, are inserted between the stool and the steel tubes for equalizing the

load distribution.

Transverse Load Application & Reaction

A U-type clamp is mounted in the middle of the one of the side frames on the

existing bracket welded to the bogie frame. The transverse load is applied

centrally with the help of the +10 t capacity dynamic actuators, held horizontally

on the specially designed brackets mounted on the test bed. Transverse reaction

is taken at all the axle box locations by suitable reaction brackets clamped on the

test bed.

Tractive Load / Braking Force & Reaction

Longitudinal loads, simulating tractive / braking load and their reactions, are

applied on the bogie frame separately. For the purpose of braking force, loads

are applied simultaneously at four brake hanger locations, through two static

jacks in the upward direction, and through two pre-calibrated helical springs in

the downward direction. The tractive / braking loads are applied on the two

anchor links in the same direction through two static jacks mounted horizontally

on the two brackets, and their reactions are taken in the opposite direction at the

end of each side frame.

Visual Examination

Visual examination of the bogie frame is to be done regularly throughout the test

to check if any crack or deterioration in the bogie frame.

31

7. Conclusion

During this Summer Training at RDSO Lucknow, I learned a lot about the

working procedure of testing of various components of IR which are Stresses in

wheel, Brake Blocks, Air Brakes, bogie frames for fatigue testing and come to

know about the use of technology for simulating and setting standards for the

components working and life through these research facilities. RDSO is one of

the prestigious organisations not only in India but in the World. There are many

technologies which are few in the world, and are available at RDSO Lucknow

for Research and Development are observed by me during this training. Practical

aspects of the working of components are gained through these training. This

training has also covered the research area in which the organisation is working

and through these training it will enhance our minds for utilizing our skills and

knowledge for giving better solutions.

This report is the outcome of time spends to learn through every source. I tried

to give my best effort on this trying to learn & compiled this report. But due to

time constraint it may be possible that I had left something which will be

covered in future through study and research.

32

8. References

[1] http://www.rdso.indianrailways.gov.in/view_section.jsp?lang=0&id=0,1

[2] WELCOME TO RDSO CMS Team Last Reviewed on: 13-06-2012

[3]WELCOME TO RDSO CMS Team Last Reviewed on: 03-05-2011

[4] http://www.rdso.indianrailways.gov.in/works/uploads/File/publication_section.pdf

[5] “An Overview of the R&D Center of Indian Railways” by Wadhwa, Gopal Krishan

(September 2003)

[6] http://www.railway-technical.com/air-brakes.shtml

[7]https://www.aarpublications.com/Publications/Manual%20of%20Standards%20and

%20Recommended%20Practices.aspx

[8] http://www.uic.org/

[9] http://www.irfca.org/docs/brakes/brake-comparison.html

[10] A.Cera, G.Mancini, V.Leonardi, L.Bertini, “ Analysis of methodologies for

fatigue calculation for railway bogie frames”

[11]RDSO-Manual for testing & standards.

*Photographs courtesy by-www.rdso.indianrailways.gov.in