PERMANENT WAY or RAILWAY TRACK: Definition, Components of a Railway Track, Requirements of an ideal permanent way



A permanent way or a railway track can be defined as the combination of rails, fitted on sleepers and resting on ballast and sub grade.

Components of a Railway Track:

The Typical components are: 1. Rails

2. Sleepers (or ties)

3. Fasteners

4. Ballast (or slab track)

5. Sub grade

Components of a Railway Track

The rails are joined in series by fish plates and bolts & they are fixed to sleepers by different types of fastenings. The sleepers properly spaced, resting on ballast are suitably packed and boxed with ballast. The layer of ballast rests on the prepared sub grade is called as the formation.

The rails transmit the wheel load to the sleepers. The sleepers hold the rails in proper position and transmit the load from rails to ballast. The ballast distributes the load over the formation and holds the sleepers in position.

On curved tracks, super elevation is maintained by ballast and the formation is leveled. Minimum ballast cushion is maintained at inner rail, while the outer rail gets kept more ballast cushion. Additional quantity of ballast is provided on the outer cess of each track for which the base width of the ballast is kept more than for a straight track.

Requirements of an ideal permanent way:

  • The gauge should be uniform and correct.

  • Both the rails should be at the same level in a straight track.

  • On curves proper super elevation should be provided to the outer rail.

  • The permanent way should be properly designed so that the load of the train is uniformly distributed over the two rails.

  • The track should have enough lateral strength.

  • The radii and super elevation, provided on curves, should be properly designed.

  • The track must have certain amount of elasticity.

  • All joints, points and crossings should be properly designed.

  • Drainage system of permanent way should be perfect.

  • All the components of permanent way should satisfy the design requirements.

  • It should have adequate provision for easy renewals and repairs. 

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