Guard rail (rail transport)

This article is about railway infrastructure. For highway infrastructure, see Guard rail.

In rail transport, guard rails or check rails are rails used in the construction of the track, placed parallel to regular running rail to keep the wheels of rolling stock in alignment to prevent derailment. They are generally used along areas of restricted clearance, such as a bridge, trestle, tunnel, or level crossing. They also help to minimize damage to the structure and allow easier post-accident cleanup.

Guard rails at Diêu Trì railway station, Vietnam

This curved track in Myanmar, near Pekon, includes a guard rail on the inside rail of the curve

History

Although guard rails in some form have been used as long as there have been trains, the precursor of the guard rails in use today was detailed in U.S. patent 522,038, filed in 1893 by Gorham B. Ames, based in Laconia, New Hampshire, US.

Applications

Bridges

The object of the guard rail is to prevent a derailed truck from getting far enough off the track to strike any portion of the girder, or from becoming twisted so as to lead to further derailment ... guard rails are requisite, so arranged as to bring a derailed truck nearly back to its proper position and guide it across the bridge without allowing it to deviate more than a few inches from the rails.

Massachusetts Board of Railroad Commissioners, Report of the Board of Railroad Commissioners in Relation to the Accident on the Boston and Maine Railroad (Western Division), Near Bradford, January 10, 1888

Guard rails on a bridge in West Virginia

Guard rails are an essential component of railroad bridges. Their presence prevents a derailed train from striking and damaging bridge components, or deviating from the track enough to leave the tracks entirely and roll over or fall.

Sharp curves

On sharp curves, guard rails may be placed inside the inner rail, where they engage the back of the flange of the wheel on that side.

Switches

Guard rails in use on a switch

Guard rails may be incorporated in switches, where they serve to prevent derailments caused by a train's wheels passing through the wrong side of the frog (the point where the straight and diverging rails cross). Guard rails in this case are typically bolted to the traffic rails on each end, with a clamp placed towards the center to prevent movement.

See also

• Guide bar
• Guide rail

External links

• Media related to Guard rails (rail transport) at Wikimedia Commons