THE SIGNAL BOX

BLOCK SYSTEM

BLOCK SYSTEM

8. Shunting

On this page:
[ Into forward section | Running round | Wrong direction | Following trains ]


Some shunting manoeuvres were touched on in in Chapter 3 in connection with Blocking Back. Here are some other activities warranting special arrangements.

New "improved" layout at Signal Box "B"

Shunting into forward section

This regulation may only be used where specially authorised on the signal box Special Instructions. If a train requires to draw into the section ahead during shunting, such as an Up Train at our Box "B" needing to cross to the Down Line through points 9, Bert will send the Shunt into forward section bell signal (3-3-2) to Charlie at Box "C". Charlie will acknowledge the signal, and place his block to Train on Line.

Bert can then clear his signal for the train to draw ahead. Sometimes a special "shunt ahead" signal is provided for this purpose (signal 3), but if not, the main signal (2) may be cleared.

If Bert's signal is electrically released by the block instrument showing Line Clear (which is a common safety feature) the actions are slightly different. Charlie will place the block to Line Clear when he acknowledges the 3-3-2 bell signal. As soon as Bert has cleared his signal, he sends Train entering section which, of course, is acknowledged by Charlie and the block is then placed at Train on Line.

When the shunting manoeuvre has withdrawn back clear of the block section, Bert sends Shunt withdrawn (8 beats) on the bell to Charlie, who acknowledges the signal and replaces his block to Normal.

There are times where it is necessary to shunt ahead where no Special authority is granted for the use of this regulation. In such instances, the train must be signalled as a normal train, and subsequently cancelled with the 3-5 bell signal, as detailed in Chapter 7.

Blob

Running round trains in block sections

"Running round" is railway jargon for shunting a locomotive from one end of a train to the other. Sometimes this can be achieved without occupying the block section (at a box with two crossovers, or within sidings) but sometimes it is necessary to do this on a running line in the block section between to boxes.

For example, a passenger train hauled by a tank engine arrives at Box B in the Up Platform, where it terminates and disgorges its passengers. It requires to draw forward to run round between B and C before crossing to the Down Line for its return journey.

Bert will signal the train forward in the normal manner with the appropriate Is Line Clear? bell signal, which is in this case 2-2-1 for Empty coaching stock. The train is allowed to draw forward, stopping just clear of the crossover points 9. The engine uncouples and proceeds to Box C.

Charlie, at Box C, will signal the engine back to Bert in the normal manner on the Down Line with Is Line Clear? signal 2-3. As soon as the conditions ahead of Charlie's Up Home signal are as they were when he accepted the train, Charlie sends Engine Arrived (2-1-3) on the bell to Bert. The emphasised phrase in the sentence is important - if the train was accepted in the normal manner, the clearing point must again be clear, but if the train was accepted under the Warning Arrangement it need not.

When the engine arrives at Bert, he crosses the engine over to the Up Line, so it may attach to the train. The train can then be drawn into the Down platform (which, as an aside, would require Bert to Block back to both Charlie and Doris). After the train has been withdrawn from the block section, Bert sends Train drawn back clear of section (3-2-3) to Charlie who then restores the block to Normal.

If, after running round, the train requires to proceed (propelling) along the Up line to Box C, it may do so. After arrival, Charlie will simply send the Train out of section signal.

Sometimes this regulation is applied where a different engine is attached to the rear of the train than was detached from the front. This is where the Engine arrived bell signal is crucial - otherwise the section might be assumed to be clear when Bert sends 3-2-3 with the detached engine still in the section. Additionally, if the move is to be propelled forward to Box C, this must not commence until Engine arrived has been received by Bert.

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Working in wrong direction

This is another regulation that is only permitted where authorised on the signal box Special instructions. Such authority was usually only granted where the block sections were short and the signals were interlocked between the boxes.

If Charlie at Box C wants to send a train in the Down direction along the Up Line to Box B, he would send the Working in wrong direction bell signal (2-3-3) to Bert. If Bert is able to accept this train and has his points safely set, he will acknowledge the bell signal, on receipt of which Charlie will place the block indicator to Train on Line. When the train has arrived at Box B, and is clear of the block section, Bert sends the Train clear of section bell signal (5-2) to Charlie, who will acknowledge it and replace his block indicator to Normal.

If for any reason the move does not proceed through the block section, but leaves the section at Box C, Charlie will send Train withdrawn (2-5) and, when acknowledged, replace the block to Normal.

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Shunt train for following train to pass

This was surely the most pointless bell signals in the 1960 regulations. It required that if Bert was offered a train by Arthur of higher importance than a train that was still in the block section between Box B and Box C, he should send Shunt train for following train to pass (1-5-5) to Charlie at Box C. If Charlie is unable to shunt the train out of the way, he will immediately send the bell signal to the next box ahead.

The bell signal was also permitted to be used when the section ahead was occupied by a Blocking back manoeuvre.

In practice, the bell signal was rarely used seriously as use of the telephone was a far more realistic way to regulate priority traffic. The only times the bell signal tended to be used was in a form of sarcasm - perhaps dropping a hint to the next signalman that he may have forgotten to send Train out of section.