l2 - rail track

Rail Tracks

What is rail track?

• Used on railways to guide trains without the need for steering.

• Consists of 2 parallel steel rails which are laid upon sleepers (or cross ties) that are embedded in ballast to form the railroad track.

• The rail is fastened to the ties with rail spikes, lag screws or clips such as Pandrol clips.

What is rail track?….cont’d

• Steel rail – can carry heavier loads by spread the load from the rails over the ground and also serve to hold the rails a fixed distance apart (called the gauge)

• Rail tracks are normally laid on ballast, which combine resilience, some amount of flexibility & good drainage.

• Steel rail can also laid onto concrete slab (aslab track)

• Across bridge – track is laid on ties across longitudinal timbers or longitudinal steel girders.

What is rail track?….cont’d

• Ballast– Track ballast, consisting of gravel, cinders or other

aggregate, forms the trackbed upon which railroad ties (US) or railway sleepers (UK) are laid. It is used to facilitate drainage of water, and to create an even running surface. This also serves to hold the track in place as the trains roll by.

What is rail track?….cont’d

• Sleepers– A railroad tie, cross tie, or sleeper is a rectangular object

used as a base for railroad tracks. Sleepers are members generally laid transverse to the rails, on which the rails are supported and fixed, to transfer the loads from rails to the ballast and sub grade below, and to hold the rails to the correct gauge.

– Traditionally, ties have been made of wood, but concrete is now widely used, steel has been used, and plastic has been tried.

Types of rail track

• Steel rail track• Concrete track• Single track• Double track– Non –parallel double track– Handedness– Bi-directional running

Rail sizes

• Expressed in terms of pound per yard or kilograms per metre.

• But pound per yard is almost exactly double the kilograms-per-metre

• Eg. – 40kg/m = 81lb/yd– 115lb/yd = 57kg/m

Method for rail track

• Jointed track

Method for rail track …cont’d

• Continuous welded rail (CWR)

What is rail track?….cont’d

Wooden sleepers

Iron & brick sleepers

Method for rail track …cont’d

Concrete sleepers Steel sleepers

Method of fixing rail to sleepers/ ties

Rail clip Fishplate

Method of fixing rail to sleepers/ ties….

• Type of fastener depends on the type of sleeper– Spikes = wooden sleepers– Clips = concrete / cement sleepers

• A baseplate or fishplate is used the between rail & wooden sleepers – To spread the load of the rail over a large area of

the sleeper.

What is rail track?….cont’d

• Track maintenance– Common maintenance job• Spraying ballast with weedkiller to prevent weeds

growing through & disrupting the ballast – special weed killing train• Leveled, cleaned & replaced ballast• Inspection – nondestructive testing method to detect

internal flaws in the rails – inspection car.• Replacing broken/ worn-out rails – periodically.