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Trivia: Longest lever "throw" (distance between box and signal)

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najaB

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Just on a train passing through Scropton and it seemed to be quite a long cable run between the signal box and the semaphore signal - can't measure distances on the Google Maps app, but I'd wager it was north of 750m.

So, the question: where on the network had the longest distance between signal box and lever-worked signal, and what is the longest distance these days?
 
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edwin_m

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Just on a train passing through Scropton and it seemed to be quite a long cable run between the signal box and the semaphore signal - can't measure distances on the Google Maps app, but I'd wager it was north of 750m.

So, the question: where on the network had the longest distance between signal box and lever-worked signal, and what is the longest distance these days?
A semaphore distant on a high-speed route could have been over a mile. Although many of those were converted to colour light starting before WW2, partly for that reason and partly to make them more visible when approached at speed.
 

Parham Wood

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Gain stroke cranks can be used to magnify the lever throw if the distance is long. These are hung under the signal lever and by an arrangement of pulleys amplify the throw of the lever. Signal wire can change in length by up to about two feetl over a 2000ft length. The signalman will have a screw he can turn to lengthen or shorten the wire so the signal arm is in the correct position. I have seen a gainstroke crank in the wire run as well although these are rare. Max hand operated point distance was 350yds.
 

SouthStand

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Doesn't "throw" in this example mean the distance the lever needs to be moved from one setting to the other, not the length of the cable joining the signal/lever?
 

30907

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Doesn't "throw" in this example mean the distance the lever needs to be moved from one setting to the other, not the length of the cable joining the signal/lever?
I wondered to9, but the OP makes what is meant clear - is "pull" the correct term?
 

najaB

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Doesn't "throw" in this example mean the distance the lever needs to be moved from one setting to the other, not the length of the cable joining the signal/lever?
I suppose so, yes. I'll update the thread starter.
 

edwin_m

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Gain stroke cranks can be used to magnify the lever throw if the distance is long. These are hung under the signal lever and by an arrangement of pulleys amplify the throw of the lever. Signal wire can change in length by up to about two feetl over a 2000ft length. The signalman will have a screw he can turn to lengthen or shorten the wire so the signal arm is in the correct position. I have seen a gainstroke crank in the wire run as well although these are rare. Max hand operated point distance was 350yds.
And point rodding can have a clever gadget that changes the stroke from a push to a pull about half way to the point. This means that (assuming both parts are exposed to similar levels of sunlight) the expansion in one half cancels out that in the other.
 

Flying Phil

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And point rodding can have a clever gadget that changes the stroke from a push to a pull about half way to the point. This means that (assuming both parts are exposed to similar levels of sunlight) the expansion in one half cancels out that in the other.
Are they those double "L" shaped connected bell cranks? I wondered what they actually did!
 

Ashley Hill

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And point rodding can have a clever gadget that changes the stroke from a push to a pull about half way to the point. This means that (assuming both parts are exposed to similar levels of sunlight) the expansion in one half cancels out that in the other.
Expansion cranks.
 

John Webb

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A semaphore distant on a high-speed route could have been over a mile. Although many of those were converted to colour light starting before WW2, partly for that reason and partly to make them more visible when approached at speed.
The LMS had a policy from around the 1930s of converting 'remote distants' (ie those not part of a gantry of signals) from semaphore to colour light signals (CLS). There were several reasons:
* Easier for train drivers to see in the more prevalent fog/smog of those times. This eliminated the need to pay overtime to a permanent-way staff member to sit in foggy weather at the base of a distant signal with detonators and a hand-lamp to reinforce the aspect the mechanical signal was showing;
* eliminated the cost of the maintenance of a mile or more of wire running over numerous small pulleys at the side of the track.
It also made life easier for the signaller - and the lever handle in the box would be cut down in length to remind the signaller they were now only working an electric light 'switch' rather than needing a two-handed pull to operate the mechanical signal.

In the archive at St Albans South we have the original 'Sighting Form' from when our Down Distants were converted to CLS in December 1938. Of considerable interest is the fact these were three aspect signals - a green light, a main yellow light and an auxiliary yellow - the latter being switched in should the main yellow lamp fail. In addition the Down Slow could also show a double yellow by using the auxiliary lamp when the train was to use the Down Slow to Down Fast crossover at St Albans South. But this feature has been crossed out in a different hand to the rest of the form; we think this happened after the Bourne End accident in 1945 when the Railway Inspectorate were highly critical of this use of a distant signal! (See https://www.railwaysarchive.co.uk/documents/MoT_Bourne1945.pdf for the detail.)
 

matchmaker

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Maryhill Park Junction in Glasgow no. 21 distant was well over 2000 yards. On a hot day there was no chance of getting a clear "off".
 

Taunton

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And point rodding can have a clever gadget that changes the stroke from a push to a pull about half way to the point. This means that (assuming both parts are exposed to similar levels of sunlight) the expansion in one half cancels out that in the other.
There was one of these in the rodding runs directly alongside the footsteps of the bridge west of Taunton station where all my initial interest was kindled long ago. It was a fascination to me how it did it, and I was always keen to see those points reversed. I used to sketch how it worked at the back of my notebook in quiet moments between Warships - and I did likewise here just a moment ago!
 

Parham Wood

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And point rodding can have a clever gadget that changes the stroke from a push to a pull about half way to the point. This means that (assuming both parts are exposed to similar levels of sunlight) the expansion in one half cancels out that in the other.
Or contraction in cold weather!
 

LYRobert

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I have mentioned this on here before, a year or two ago. There was a semaphore distant at the end of the embankment but before the cutting above Cliviger, near Burnley. It was worked from Townley box, just over a mile away. Somewhere along this length was a device mounted on a short post in the cess, comprising a balance weight and some chain pulleys. I never got the opportunity to examine this apparatus closely, being carried along in a train (ex Blackpool - Todmorden) every time. I assumed it was some kind of compensating device for the long pull the distant required. However, one of my workmates' Dad was a signaller, normally at Portsmouth (that's on the Copy Pit line, not on the south coast), and he sometimes he had to work the Townley box. He said that that distant was a pig to pull off in warm weather, there was a repeater in the box but you could never get it to show beyond 'half'. He said engine crews said that the signal suffered from "Brewer's droop". It was important to the engine crews because they were on a falling gradient, and Townley box worked a level crossing which wouldn't be cleared until the last minute, and that distant would indicate a clear run through - or not.
 

edwin_m

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When boxes were close together, the distant(s) for the first one would often only clear when all the stop signals from several boxes were also clear. This was sometimes done by a mechanical slotting arrangement within the box, so the first signalman could reverse his distant lever but the signal wouldn't clear until the man further down the line had done the same. These signals were often also on the same post as stop signals, therefore slotted with them too. On occasional however there was no interlocking provided, and the first signaller was relied on to observe the distant for the next box clear (or a special indicator in the box if the signal itself wasn't visible) before clearing his own distant.
 
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