scope:

GENERAL DESCRIPTION.

ABCL is a form of level crossing protection introduced following the Stott report and the accident at Lockington. ABCL's appear identical to AHB's to a road user, while to traincrew, their appearance and operation is similar to AOCL's.

Protecting signals shall be provided within 10 minutes running time at permissible speed. This limit shall not apply in RETB or ERTMS areas where there is continuous voice communication between train and signal box or arrangements are in place for each train to contact the signaller and obtain permission before proceeding over the crossing.

Where a protecting signal is not directly controlled or slotted by the signal box supervising the crossing, arrangements shall be in place to alert the signaller controlling the protecting signal to replace it to danger quickly in an emergency.

NOTE In an absolute block area, then sending "6 bells" is sufficient. In other areas an emergency alarm or similar shall be provided.

Automatic barrier locally monitored crossings, have barriers pivoted at the nearside of the road, and of length up to the centre line of the road. The exit sides of the roads are kept clear to allow slow moving vehicles to clear the crossing.

Each road approach is protected by a minimum of two road traffic light signals (RTL's). One unit is sited on each side of the road approach.

Audible warnings are provided for pedestrians. There are a minimum of two units. They shall be normally sited at the diagonally opposite nearside corners of the crossing facing onto the crossing area. Larger crossings may use four audible warning devices with one at each corner.

A drivers crossing indicator (DCI), is provided on each rail approach at a nominal distance of 5 Metres.

Driver's emergency plungers are normally provided on each rail approach. They are contained in a locked box located nominally 2m in advance of the DCI. Thelock is a drivers No 1 key. It is not required to prove that the doors of the emergency plunger box are closed and locked.

NOTE Older crossings may not be fitted with emergency plungers

A scaled ground plan defines and locates all equipment sited at the level crossing.

Telephones for users are normally provided but are not mandatory.

Where trains run at night, the crossing has floodlighting that activates when a train is approaching. This allows the driver of a train to check the crossing is clear. The floodlighting is arranged as far as practical so that it is pointed at the crossing surface and does not cause glare to approaching trains.

Barriers employed at ABCL crossings shall remain in the raised position in the event of a total power failure.

Before the barriers are allowed to descend automatically, sufficient flashing red road signals shall be functioning. Loss of any further road signals during the descent shall not prevent them fully lowering.

The maximum length of trains permitted to operate over the level crossing shall be documented in the design details.

intended Use:

Superseded by NR/L2/SIG/11201/ Mod X11 Issue 2, June 2012, which is in Word format and attached to thr front sheet of NR/L2/SIG/11201 ISSUE 8.