What is Railway Sleeper?
A railway sleeper is a part of the railway track. Sleepers are placed below the rails and over the ballast. The main function of the sleepers is to distribute the loads coming on the rails over a large area of the ballast and support the rails to hold them firmly in place. It provides stability to the permanent way.
Different Types of Railway Sleepers
How many types of railway sleepers are there? According to the use of materials, railway sleepers are classified into the following categories:
- Steel Sleepers.
- Timber or Wooden Sleepers.
- Cast Iron Sleepers.
- Concrete Sleepers.
1. Steel Sleepers
Due to the growing scarcity of wooden sleepers, and their short life span, steel sleepers have now become more popular in every part of the world.
Advantages of Steel Sleepers
The following are the advantages of Steel sleepers:
1. Steel sleepers are uniform in strength and durability.
2. The efficiency of fittings is better in Steel sleepers and therefore less creep develops.
3. They are economical because they are longer in life and easier to maintain.
4. In steel sleepers, the Gauge can be easily adjusted and also easily maintained.
5. For Steel sleepers, there is no need for frequent renewal.
6. They have a good scrap value.
7. They are not susceptible to fire and vermin attacks.
Disadvantages of Steel Sleepers
The following are the disadvantages of steel Sleepers:
1. More ballast is required than other types of sleepers.
2. These sleepers require a number of fittings which causes difficulties in maintenance.
3. These sleepers are liable to rusting/corrosion.
4. These sleepers are not suitable for track circuiting.
5. Steel sleepers are unsuitable for bridges, level crossings, points and crossings, etc.
6. These sleepers are only suitable for stone ballast.
Note: Steel sleepers and cast iron sleepers are the types of metal sleepers
2. Wooden Sleepers
Wooden sleepers are considered the best as they fulfill almost all the requirements of an ideal sleeper. In most cases, the most commonly used timbers for sleepers are oak, sal(Shorea robusta), and teak.
Advantages of wooden sleepers
Following are the advantages of wooden sleepers
1. The initial cost of a wooden sleeper is low.
2. Timber is easily available in all parts of the USA, UK, and India.
3. Fittings for wooden sleepers are few and simple in design.
4. These sleepers are able to resist shocks and vibrations due to heavy moving loads and also provide a noise-less track.
5. Wooden sleepers are easy to lay, relay, pack, lift, and maintain.
6. They are suitable for all types of ballast.
7. They are best for track-circuited operations.
Disadvantages of wooden sleepers
The following are the disadvantages of wooden sleepers
1. The service life of wooden sleepers is short(12 to 15 years)as compared to other types of sleepers.
2. These sleepers are subjected to wear, decay, and attack by white ants, spike killing, cracking, etc.
3. It is difficult to maintain the gauge in the case of wooden sleepers.
4. The track is easily disturbed. Hence alignment maintenance is difficult.
5. The maintenance cost of wooden sleepers is high as compared to other sleepers.
6. The scrap value of these sleepers is very low.
7. They are susceptible to fire.
3. Cast Iron Sleeper
Cast iron sleeper is another type of sleeper, which is extensively used in India. It is also used in South America, Burma, and Pakistan. Cast iron slippers have been used in India since 1870.
Advantages of cast-iron sleepers
Following are the pros or benefits or advantages of cast-iron sleepers
1. The probability of cracking is less.
2. They have less corrosion effects.
3. The scrap value is high in the case of cast iron sleepers.
4. The manufacturing process of cast iron sleepers is comparatively easy.
5. Maintaining work for this type of sleeper is minimum and easy. Therefore, less-skilled labor is required.
6. It provides good longitudinal as well as lateral resistance.
7. Cast iron sleepers are not affected due to the irregular falling of fire from the steam engines.
8. The efficiency of fittings is also better in cast iron sleepers; therefore, less creep develops. Read Also: Creep of Rails
Disadvantages of cast-iron sleepers
Following are the cons or drawbacks or disadvantages of cast-iron sleepers.
1. Ballast requirement is more compared to the other types of sleepers.
2. In these sleepers, more fittings are required, and frequent Inspection is essential.
3. Cast iron sleepers are not usable for track-circuited areas as they are good conductors of electricity.
4. They are not suitable for level crossings and bridges.
4. Concrete Sleepers
The first idea about concrete sleepers was conceived by Monier of France in 1884. However, it takes several years to become popular in different countries. After world war II it was rapidly developed due to the scarcity of timber. Especially in countries like the United Kingdom, Germany, France, Russia, and Japan. During world war II, many of the railway lines were destroyed in these countries, and the shortage of wood forces them to find a suitable alternative sleepers material of timber sleepers. Finally, the concrete sleeper became one of the most popular sleeper types.
Advantages of Concrete Sleepers
Following are the Pros or Benefits or advantages of concrete sleepers
1. Concrete sleepers give more strength and stability to the track.
2. They have great resistance to buckling of the track.
3. A concrete sleeper is a poor conductor of electricity. For this reason, they are preferred for track circuited areas.
4. It has a very long lifespan. It can last 30 to 40 years.
5. It has economic benefits due to its long lifespan and minimal joints.
6. Concrete sleepers are free from natural decay and the effect of chemical action.
7. They are not attacked by insects or vermin.
8. They are not affected by the adverse environmental effects.
9. They can be produced in a large volume using local resources.
Disadvantages of Concrete Sleepers
Following are the cons or drawbacks or disadvantages of concrete sleepers
1. It has no scrap value
2. The maintenance and replacement process is difficult.
3. Transportation is difficult as they are heavy in weight.
4. They are heavily damaged at the time of replacement.
5. Concrete sleepers are not suitable for better packing.
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