What is a rail anchor?

When a train is running, longitudinal forces often act on the rails, causing the rails to move longitudinally, and sometimes even driving the sleepers to move together. This longitudinal movement is called creeping. Creeping generally occurs in double-track railway sections and single-track railways, where heavy-loaded vehicles are guided on ramps and parked and braked.

Track creeping is often caused by uneven track gauges, skewed sleepers, etc., which damages the line and even derails the vehicle, endangering driving safety. Therefore, effective measures must be taken to prevent creeping, and rail anchors are usually used to prevent track creeping.

Rail anchors specifications

Design Features of rail anchors

Rail anchors are widely used in railway construction projects to prevent rail movement. Track pads are welded onto the top surface of the lower edge of the rail. Generally, the track pads overhang the side of the rail by 100 to 150 mm. Rail anchor blocks are then welded to the rail support surface to prevent longitudinal movement of the rail. These pads are positioned away from the edge of the rail and do not affect the lateral adjustment of the rail. Track welding requires low hydrogen (or austenitic) electrodes and an appropriate degree of preheating. This will depend on the carbon content or carbon equivalent of the rail steel. rail anchors must be welded without damaging the pads under the rail. The rail temperature should always be kept below 150˚ C when installing rail anchors. An alternative to central fixing points is to use pads at the end of the rail. These are usually welded to the rail support, about 50 to 100 mm from the end of the rail. This is usually a better solution to ensure that the track does not move, rather than using fixing points.

Location of rail anchors

Typically, rail anchors are used at certain locations on the railroad. When anchors are used, eight rail anchors are usually recommended for a 39-foot long track. The number of rail anchors may increase as the grade increases.
rail anchors are used on tracks approaching open-air bridges, and every third sleeper should be box-anchored at least two track lengths on each end of the bridge.
At railroad crossings where anchors are used, every third sleeper should be box-anchored at least two track lengths in each direction of the crossing.
Rail anchors are optional in railroad turnouts. When anchors are used in turnouts, it helps correct geometry problems.