Railway Sleepers Definition, Characteristics, Treatment

1. Railway Sleepers Definition

It is a component of permanent way laid transversely under the rails and performing the following functions.

To support the rails firmly and evenly
To maintain the gauge of the back correctly
To distribute the weight common on the rails over a sufficiently large areas of the ballast
To act as an elastic medium between the rail and the ballast and to absorb the vibrations of the trains.
To maintain the track at proper grads
To align the rail properly

2. Characteristics of Ideal Railway Sleepers

Initial cost and maintenance cost should be low
They should resist weathering, corrosion, decay and other deterioration
They should bear the wheel load efficiently and satisfactorily
They should maintain the correct gauge
They should absorb shocks or vibrations due to moving vehicles
It should distribute the load properly and uniformly over the ballast
Fastenings of rail with sleepers should be strong and simple
They should not break while packing of ballast
Weight should not be low or high

3. Types of Railway Sleepers

Depending upon the position in a railway track, sleepers may be classified as:

1. Longitudinal Sleepers

2. Transverse Sleepers

i. Timber / wooden sleepers

ii. Steel Sleepers

iii. Cast Iron Sleepers

iv. Concrete Sleepers

4. Treatment of Wooden Sleepers

Untreated railway sleepers are prone to attack by decay and vermin. The life of untreated wooden sleepers is thus very less. The life of untreated sleepers can be prolonged considerably by treatment. An extra life of 30-50% is estimated for treated sleepers over untreated railway sleepers.

The fibers of wood contain millions of minute cells containing juices. When these juices ferment, they lead to decay of timber. In the treatment process these juices are removed as much as possible and cells are filled with some preserving solutions may be an oil or some salt solution.