ELEMENTS OF PERMANENT WAY , rails, their use, types, significance etc

Railway engineering , rails

1. ELEMENTS OF PERMANENT WAY RAILS

2. REQUIREMENTS OF IDEAL PERMANENT WAY A uniform and correct gauge are necessary. The level of both the rails should be the same on a horizontal track. At the curved locations, super elevation in a permanent way must be provided properly by raising the outer rail of the track. The design of the permanent way should be done in such a way that the load is uniformly distributed between two rails.  The track should possess the required elasticity and lateral strength. All joints, points and crossings should be properly designed in a permanent way. The drainage system must be properly installed. Scope for maintenance and renewables must be provided.

3. Components of Permanent Way Rails Sleepers Ballast  Fixtures and fastening Track geometry : cross section of permanent way

4. Rails are made up of steel girders which provide a levelled and continuous surface for the smooth movement of rolling stock. Rails also serve as lateral guides in turning operations, carry stresses produced from the vertical loads and transmit the load to the ballast and finally to the subgrade and formation.  Types of Rails  The rails used in construction of permanent way are of following types: Double-Headed rails Bull-Headed rails  Flat-Headed rails RAILS

5. Double Headed Rails (D.H. rails) Double-headed or Dumb-bell rails are rail sections with the same dimensions at the foot and head. Initially , these rails were widely used in railway tracks. The idea behind using these rails was that when the head of the wheel wore out from rubbing, the rails could be inverted and reused. However , it was discovered through experience that their foot could not be used as a running surface because it became corrugated under the impact of wheel loads. This type of rail is no longer used by Indian Railways.

6. Bull Headed Rails (B.H. rails) Bull-headed rails are rail sections with larger head dimensions than their foot dimensions. By adding more metal to the head of this type of rail, it is made slightly thicker and stronger than the lower part. Chairs are also required to keep these rails in place. Bull-headed rails are particularly useful for establishing points and crossings. B.H . rails provide better smoothness and alignment. However, they require heavy maintenance.

7. Flat Headed Rails (F.H. rails) Flat-headed rails are rail sections with their feet rolled flat . Charles Vignole invented this type of rail in 1836. Initially, it was thought that the flat-footed rails could be fixed directly to wooden sleepers, eliminating the need for chairs and keys required for the B.H. rails. However , it was later discovered that heavy train loads caused the rail's foot to sink into the sleepers, causing the spikes to come loose. To correct this flaw, steel bearing plates were installed between the flat-footed rails and the wooden sleeper. In India, these rails are most commonly used.