- This topic has 4 replies, 2 voices, and was last updated May 23, 2020 at 1:15 pm by RailWest.
May 22, 2020 at 4:21 pm #163743RailWestParticipant
There were many places where a ground-level shunt signal was used as a ‘running shunt’ in advance of a main running signal, so the former had to be cleared first before the latter could be cleared. But…were there ever any instances where either (1) a GWR ‘backing’ signal or (2) a Stevens-type ‘bow tie’ arm as used by the L&SWR and others as a ‘wrong road’ signal were used as a running shunt in a route signalled for passenger traffic?May 22, 2020 at 11:59 pm #163758Mike HodgsonParticipant
Can you really call it a bang road route if passenger movements are signalled bi-directionally?
But I remember the model railway magazines sometimes used to publish photos of the unorthodox and improbable under the caption “prototype for everything”.May 23, 2020 at 10:28 am #163777RailWestParticipant
>>>Can you really call it a bang road route if passenger movements are signalled bi-directionally?
A good question, but what if it had originally been a ‘wrong road’ move only, but then later was also signalled for passenger traffic?
There were certainly a couple of examples on the S&DJR where the ‘bow tie’ arms were used for right-direction moves. Given that they described all such arms simply as ‘Shunt…..’, I suspect that they may have used the ‘bow tie’ arm in such cases in order to provide better visibility than an ordinary small shunt signal. Perhaps the same rationale applied to the GWR’s use of elevated ‘backing’ arms rather than ground-level shunts, although I am aware of course that their function was slightly different.May 23, 2020 at 1:09 pm #163786Mike HodgsonParticipant
I have sometimes wondered why wrong direction shunt moves were considered worthy of a special signal. Many railway companies clearly didn’t see such a need. Perhaps there was a perceived risk of misreading an elevated shunt as the starter being cleared for an adjacent road? Another possible explanation is that a tall arm might be confused for authority to proceed causing stops blocks to be hit at speed.
A shunt signal does need to be easily distinguished from a running signal, and ground signals are obviously different. A shunt movement is much the same in the right direction, although the driver is often more likely to be closer to the signal. Elevating the signal obviously helps but movements into dead-end sidings inherently involves propelling stock which generally obstructs the driver’s view of whatever else is in the yard, so there normally has to be somebody on the ground or in the van to give hand signals anyway. By day at least, a bow tie or two holes is perhaps more distinctive than merely reducing the size of a standard arm, especially where that arm is isolated rather than being on a bracket close to a full size arm.
Although the 1950 black rule book and its corporate predecessors define different types of subsidiary and shunting signal, I have never seen any mention let alone a definition of a “running shunt” in any rule book. I would describe it as a signal applicable to shunting movements but which is not co-located with a running signal – because if it were co-located, you could pass it at danger on the authority of the main signal. Is that fair and does it cover all cases? Shunting itself was defined in rule 47, but I read that as a bit unclear when applied to running shunts.
The original BoT minimum requirements on shunt signals were extremely limited, and different companies seem to have had their own ideas when it came to deciding what to provide. On purely economic considerations, shunt signals are justified if their absence costs you more in compensation for goods damaged in transit and rolling stock repairs caused by inadequate facilities to control shunting. Experience of costly mistakes would vary between companies, and some managements would be better at recognising that it isn’t good enough to blame the workforce when you don’t give them a practicable way of working.
Bow-ties (and GW backing arms?) can be on the same post or bracket as a running signal, but I guess they are just ordinary shunt signals in that case. Again I think the companies used them differently – just a question of slightly different uses being made of products in the manufacturers’ catalogues ?May 23, 2020 at 1:15 pm #163790RailWestParticipant
>>>I have sometimes wondered why wrong direction shunt moves were considered worthy of a special signal….
Might it be perhaps because they were used in situations where there would be no fixed signal to limit the movement?
>>>Bow-ties (and GW backing arms?) can be on the same post or bracket as a running signal, but I guess they are just ordinary shunt signals in that case….
I’m not aware that the co-location of such signals with a main arm (which was quite common – eg Waterloo) altered their meaning/function in any way.
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