THE SIGNAL BOX

BLOCK SYSTEM

BLOCK SYSTEM

5. The Warning Arrangement - Regulation 5

On this page:
[ Use where authorised | Acceptance | Warning the driver | Driver's duty | Train out of section | Blocking back | Clearing point later available | Emergencies | Lever collars ]


Bert's branch line is becoming very busy, but Box D is several miles away, and Down trains are often getting delayed at Box D awaiting acceptance. Bert's management want to minimise the delay and therefore decide to authorise the use of Regulation 5 - the Warning Arrangement.

Use only where authorised

The Warning Arrangement is only allowed to be used "where authorised" except in emergency, or for certain specific types of train (see Chapter 7).

The term "where authorised" means that the circumstances in which Regulation 5 can be used will be specified on the Special Instructions of the box concerned. It is normally only authorised at places where traffic congestion regularly occurs, and usually only for non-passenger trains.

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New "improved" layout at Signal Box "B"

Acceptance

If Doris at Box D offered Bert a train on the Down Branch line whilst he had a train signalled on the Down Main, he would not normally be able to accept it. However, with authority to use the "Warning Arrangement", Bert is able to accept the train for Doris in a special manner.

Instead of acknowledging the Is Line Clear? signal, he replies with the Section clear, but station or junction blocked signal 3-5-5. To signify that she has understood Bert's requirements, Doris replies by sending the bell code 3-5-5 back to Bert. Only when Bert has heard that reply may he turn his commutator to Line Clear.

The first thing Doris does on hearing the 3-5-5 bell signal from Bert is the place a Lever Collar on her starting signal, to remind herself that Bert has accepted the train under the "Warning Arrangement".

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Warning the driver

Doris needs to "warn" the driver of the train that he has been accepted under Regulation 5, so he can drive his train accordingly. There are a number of ways she can do this:

The driver's duty

On being "warned" by Doris, the driver knows there is no margin for error at Bert's home signal, and therefore drives with extra caution. If the train is not fully-fitted, i.e. not every wagon is fitted with the automatic brake, the driver is additionally required to bring his train to a stand in the first instance at Bert's distant signal. This is a way of making sure the train is under control.

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Train out of section

If the train arrives at Bert and, after the Down Main train has passed, is allowed to draw to the Down Starting signal (20) to await acceptance, Bert is allowed to send Train Out of Section to Doris although the clearing point is still occupied. He does this in a special manner - by sending the bell signal 2-1 but leaving the commutator and needle at Train on Line.

Note - on the Western Region, the commutator and needle are placed to Normal, and the following to paragraphs do not apply.

If Doris hears the Train out of Section signal, but sees the needle remain at Train on Line, she knows that Bert's clearing point is still obstructed. She can then offer Bert another train (only of the class authorised) if she wishes.

If the clearing point subsequently becomes clear, and Bert has not accepted a second train from Doris, he sends one beat on the bell to Doris and, when acknowledged, changes his commutator and needle to Normal.

Blocking back

If Bert has cause to send Blocking back inside home to Doris, the circumstances are similar to having sent Train out of section with the Clearing Point fouled, as detailed in the last paragraph.

So, as in that situation, Doris may offer a train to Bert despite the block indicator being at Train on Line.

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If the clearing point later becomes available

If Bert becomes able to accept the train under normal conditions before it has entered the section, he may send the Line now clear in accordance with Regulation 4 for train to approach signal 3-3-5 to Doris. Doris will acknowledge this bell signal, and then remove the lever collar and clear her signals in the normal manner.

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Use of Warning Arrangement in emergency

There are many circumstances detailed in the signalling regulations where special authority is not required to use the Warning Arrangement. Most of these are related to emergencies, which are outside the scope of this section.

A simple example of this kind of emergency would be if Bert had a Down train that had failed in the Down platform at No.20 signal. If an assisting engine from Box C or D needed to be coupled to the rear of the train to push it, Bert would normally be unable to accept it as the failed train is within his clearing point. Therefore, he is permitted to accept the assisting engine under the Warning Arrangement.

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Lever collars

A lever collar is a reminder appliance that can be placed on the handle of a lever. It prevents operation of the lever without its removal. There are many circumstances in the Rules and Regulations where it is compulsory to use reminders.