Signals at Blairgowrie

The day to day working of the Caledonian Railway Company, including its constituents and successors.
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tony brenchley
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Joined: Sun Aug 26, 2012 9:36 am

Signals at Blairgowrie

Post by tony brenchley »

A recent exchange of emails raised a question in my mind about the function of a bracket signal at Blairgowrie. This was the only 'complex' signal at the station the others all being single post signals with obvious functions. Presumably this signal controlled the use of the engine release crossover nearby but I am not clear about the function of each of the two signal arms.

I have attached 2 photos of the signal and a copy of the signal diagram from the CRA collection. The photos were taken by Dr George Stilley in the 1960s and the diagram dates from 1917. The crossover was laid in 1907 or 1912 and as far as I am aware the track layout in this part of the srtation remained unchanged until closure in 1965.

Can anybody help?

Tony B
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jimwatt2mm
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Joined: Fri Nov 16, 2012 5:36 pm

Re: Signals at Blairgowrie

Post by jimwatt2mm »

tony brenchley wrote:.......... Presumably this signal controlled the use of the engine release crossover nearby but I am not clear about the function of each of the two signal arms.
Tony B
I am no expert on signalling, but to my understanding signal 7 is the starter for departing trains (8 is an advance starter) and 14 is for the crossover. Why it should be a miniature arm and not a shunt signal I can't explain. Jim S is your man for this! :D

Jim W
dumb buffer
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Re: Signals at Blairgowrie

Post by dumb buffer »

Clearly, as Jim says, 7 is the platform starter and 14 controls access from the platform to the loop. The loop is not available for passenger trains (no FPL). But one has to wonder why signal 23, controlling access to the other end of the loop, is a disc (albeit up a post) rather than a minature arm. It doesn't look as if arriving goods trains would run straight into the loop. Rather it would seem that they ran into the passenger platform, then reversed into the loop before being dealt with in the yard. Do you have any details, Tony, about how goods trains were handled?

Allan F
IBrown
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Re: Signals at Blairgowrie

Post by IBrown »

I think the miniature arm has been provided in this case purely to aid signal sighting as the signal post and right hand bracket are placed not just on right of Drivers, but to the right of all the intervening roads. The corresponding signal for the opposite direction is also on right of Drivers, but I suspect Drivers have a much better approach view of it, hence the elevated disc.
dumb buffer
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Re: Signals at Blairgowrie

Post by dumb buffer »

Further perusal of the SB diagram reveals the surprising fact that only the outer starter, the distant, and one of the ground signals are on the left side of the line. The other 12 are on the "wrong" side. How common was this?

Allan F
lindsay_g
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Re: Signals at Blairgowrie

Post by lindsay_g »

Re signals at the wrong side. I've no idea of what the situation was at Blaigowrie regarding "things" that may have obstructed vision either for the drivers or the signalmen.

How common was wrong side - I've no idea. I can only comment on Barnton where the arrival 3 arm signal was situatedat the other side of the opposite double track. The line was straight enough and area flat enough such that there would have been no problems for the drivers. All in all it seemed odd. However, there was an overbridge just where the tracks to the station and yard fan out. This would have obscured the signalman's view unless a high (possibly really really high) post was installed. But, there would have been a clear view of the post through the arch of the bridge from the box (or cabin!) when it was positioned across the tracks. From that I'm assuming it wasn't just the "post" that was visible but the signal arms et al. If my layout and signal is to scale then that would have been the case.

This one was run past Jim Summers and other lesser lights with no other explanation coming forward so far. Might similar conditions have applied at Blairgowrie?

Lindsay
Jim Summers
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Re: Signals at Blairgowrie

Post by Jim Summers »

I am a bit surprised that my offering on this topic seems not to have appeared, though I thought it had been correctly sent, right after Tony's query.
Be that as it may:

As others have said, the signal is on the "wrong side", but the diagram makes clear what lines it refers to. The grouping of the numbers of the levers shows that the small arm is related to the crossover. Signals on the "wrong side" are not uncommon - sighting is the usual reason, as folk have said, but cost may be too. We did not have legislation imposing it, whereas the Germans, for example, did haved, and very expensive it was to adhere to.

I was less sure as to the reason for the expense of that crossover, as it seems to offer merely convenience over anything which the outer connections would have achieved. With the Outer Home, they may not even have needed to block back.

One feature which rather intrigued me was that the Distant is worked, which is not usually a feature at a branch terminus. The Inner and Outer Homes may have had something to do with it, but it doesn't seem awfully good practice.

Trying again,
Jim S
IBrown
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Re: Signals at Blairgowrie

Post by IBrown »

The reason for the ‘strange’ positioning of the main line running signals is that the approach to the station is on a reverse curve - the photo is the first clue which shows the line swinging sharply left away from the station. Old-maps shows that it then swings sharply right. That is why No12 Outer home signal is also on right of Drivers, if situated on the left as is usual it would be on the ‘inside’ of the curve, the Driver of a train approaching on a left hand curve would have little or no approach view of it, so although situated over on the right he can still catch sight of it from his position, or get the fireman to watch for and call out what it is showing from his side of the loco.

I suspect the layout also serves the method of working here which would almost certainly have involved mixed trains, with the ‘freight’ portion marshalled on the rear. I have no doubt that is why Nos 7/14 home signals are positioned so far from the platform ramp. Doing so allows the train locomotive release via the g/f crossover, then back the loop to outside Nos 17/19 ground signals, then back over No 16 crossover on top of the freight vehicles - where the loco would still be inside Nos 7/14 home signals. No 14 would then be cleared to allow the freight vehicles to be drawn back over 16 crossover onto the loop / headshunt and be disposed – all without blocking the single line, or stopping trains being accepted from the box in rear as the line remains clear to No 11 Inner home for the duration of these shunting movements.

I also suspect that the g/f crossover to No 16 crossover will also turn the longest freight, and arriving freights will run to the loop, and the loco run round via the g/f crossover, the platform line and No 16 crossover, then be disposed of using the loop and headshunt. I suspect the topography will prohibit the use of the single line for shunting purposes, as the train would be out of sight of the signalman.
tony brenchley
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Joined: Sun Aug 26, 2012 9:36 am

Re: Signals at Blairgowrie

Post by tony brenchley »

Thanks to all those who responsded to my query. The signal post was obviously placed in this position for sighting reasons. My original confusion arose because of the close proximity of signals 11 and 8 to the crossover but it all now makes sense.

Tony B
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