NR NR/L2/SIG/11201/MOD X22 ISSUE 2 PDF

GENERAL DESCRIPTION.

These crossings are protected by colour light or motor worked semaphores that are capable of reverting to danger automatically behind a train. These signals shall be interlocked with the barriers so that it is not possible to clear the signals unless the road is fully closed by the barriers and "Crossing Clear" confirmed by the operator.

By default these crossings shall normally have auto lower and auto raise facilities provided. Exceptions shall only be provided where extreme cost is an issue and by agreement with the operating managers.

The optimum distance between the crossing and the protecting signals is standard overlap distance. but is often varied as a result of taking into account other factors:-

• If signal spacing fit is better as a result, the protecting signals may be in the range 50m to 600m without further consideration.
• Where two crossings are sited in the same signal section, then the distance to the second crossing is usually unavoidably more than 600m. This may be minimised by moving the protecting signal to 50m from the first crossing.
• If the crossing is closed to road a significant time in any hour, then reducing to 50m minimises road closure time.
• Protecting signals may be within 50m if some appropriate SPAD mitigation is provided.

It shall not be possible to raise the barriers unless the signals are replaced to Red and are free of approach locking, or the train has passed the signals and traversed the crossing.

NOTE Where approach locking is not presently fitted, then any installation or modification work carried out to the crossing must also provide approach locking. Where it is a complete renewal or resignalling, then approach locking meeting all modern standards shall be provided. Where it is lesser work than complete renewal and the necessary infrastructure does not presently exist to support approach locking meeting modern standards, then a simpler arrangement may be provided. As a minimum a single device (such as a treadle or single track circuit occupying), can determine when a train has arrived at the crossing for releasing approach locking and semaphore protecting signals need not be light proved or arm proved "ON" in the approach locking release. (Lever in "B" position shall be sufficient.)

These crossings are protected by a minimum of two road traffic light signals (RTL's) each side of the road and lifting barriers on both sides of the railway. An audible warning to pedestrians is provided.

The crossing is supervised by an operator who shall be located within 50m of the crossing who has a full view of the crossing area, including the barriers and out at least as far as the road stop lines, from the normal level crossing operating position.

The barriers shall normally be kept raised unless required to be lowered for the passage of trains. In exceptional circumstances and only where there is a low road usage, it is permissible for the barriers to be kept lowered and only raised when required for road traffic. (See the MCB-OC section.)