Detonator Placer Symbol

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StevieG
LNER A4 4-6-2 'Streak'
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Location: Near the GN main line in N.Herts.

Re: Detonator Placer Symbol

Post by StevieG »

David Waite,
Reading through this thread, I see the possibility of confusion about detonators on diagrams, types and uses of placers etc.

1. Fog / Falling Snow : apart from a signalman's ability to deploy his own signal box-operated detonators when not having cleared his signals in such circumstances for a train to proceed into the next section, particularly if awaiting Fog/Snowsignalman/men arriving at their posts, as signal box diagrams generally depicted the signal box's equipment, and detonator-placing by Fog/Snowsignalmen was considered nothing to do with the signal box equipment, the positions for placing of Fog/Snow signalmen's detonators (however placed) were usually not shown on signal box diagrams to my knowledge.
'Fog/Snowmen' were normally required to place detonators by hand, with detonator placers for them (if any) in the vast majority of cases (e.g. on the Great Northern Railway at least), only provided where a man was dealing with parallel signals for at least two lines (possibly only three or more), where to place detonators on one or more of his lines, he had to cross one or two other lines, and it was presumably thought too risky to continually have to do this to place detonators by hand, thus placers were provided at some 'Fog/Snowmen's positions.

2. Then there were the detonator placers directly operated from the signal box.
These were usually as close to the signal box as possible, unless provided usually only short distances away in order to be at the approach to points of divergence or possibly convergence, and whose operating methods varied according to the old companies and their successors' specifications and practices, being rod-operated by, e.g., lever, or pull-up stirrup handles between levers, or operated by double-wire (push-pull) from short handles separate from the lever frame, sometimes known as 'Fog Handles'.
Some companies had the description plates of their detonator levers etc. carry the description "Emergency Detonator Placer".
Box-operated detonators could be used to draw attention of footplatemen and Guards to unsafe situations; e.g. if believing that a train was going too fast approaching signals and would pass one or more at Danger, or if an emergency suddenly arose needing cleared signals to be put back to Danger as a train was approaching/about to pass.

3. There were some locations - only found on the Great Western Railway AFAIK(?) - where two or more passenger lines converged into one, and where a train overrunning a protecting signal at Danger had been considered as particularly dangerous. In these cases, three det. placers 10 yards apart were provided beyond each protecting running signal, rod-connected with the relevant points, and the dets. were thus moved on and off the rail according to the position/s of the points.

4. Lastly there are those which were already mentioned I think, by Mickey. These are sometimes described, using perhaps a slightly modern term in the last few decades, as Co-acting detonator placers.
As said, these were sited just beyond the locations of some stop signals (perhaps those where 'Fog/Snowmen' positions might otherwise have been considered as needed), and worked in conjunction with the particular stop signal, and where this was the case, the normally all red signal levers were instead painted red on their top half, and the customary black & white chevrons for detonators on the lower half.

But as to det. placer symbols, particularly back in the early-ish times you first enquired about David, pretty sure I can't add anything to what others have said and you have discovered.

Hope some of all this is of some help / interest.
BZOH

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David Waite
GER J70 0-6-0T Tram
Posts: 14
Joined: Sun Jun 28, 2020 10:22 am

Re: Detonator Placer Symbol

Post by David Waite »

Thanks StevieG
Your input was greatly appreciated,
I’m only concerned with the detonators that were operated by levers in a signal box, I will draw the same symbol as the Midland used as these are the earliest symbols I have been able to find so far .
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