Moretonhampstead Signalling

[Pannier Tank]

10 hours ago, Harlequin said:

Here's a further revised version which I hope, after reading SRS Paper No.8, is closer to the 1920s style with later amendments.

 

Phil, thank you for the update and also for carrying out further research into Signal Diagrams, much appreciated.

[Rods_of_Revolution]

I really like the authenticity in the replication of the signalling diagrams. What do the different colours (blue, orange, grey, etc) of track mean on GWR diagrams? Also, what fonts/typeface are used?

 

Cheers,

 

Jack

[RailWest]

IIRC grey = passenger running lines, orangey-brown = goods (running) lines, blue = sidings.

[The Stationmaster]

It seems all the discussion from the other thread is not yet transferred over so i'm holding fire until that happens.  Except to say  except to say that with a ground disc reading only one way through points back in those days it would be unlikely for it to be released by the FPL.  there is obviously a need for further discussion about the point lock bar.

[Pannier Tank]

9 hours ago, The Stationmaster said:

It seems all the discussion from the other thread is not yet transferred over so i'm holding fire until that happens.  Except to say  except to say that with a ground disc reading only one way through points back in those days it would be unlikely for it to be released by the FPL.  there is obviously a need for further discussion about the point lock bar.

 

Andy Y said he would take a look at moving the relevant posts to this thread on Monday.

 

Edited March 29, 2020 by Pannier Tank

[Harlequin]

Not specifically about signalling but I found some images of Moretonhampstead I hadn't seen before here: https://thetransportlibrary.co.uk/?route=product/search&search=Moretonhampstead&category_id=148&page=1

The photos were taken in the 50s when it was still a working station, although you can see that the engine shed was being used as a coal store by then.

 

Edited March 31, 2020 by Harlequin

[Pannier Tank]

8 minutes ago, Harlequin said:

Not specifically about signalling but I found some images of Moretonhampstead I hadn't seen before here: https://thetransportlibrary.co.uk/?route=product/search&search=Moretonhampstead&category_id=148&page=1

The photos were taken in the 50s when it was still a working station, although you can see that the engine shed was being used as a coal store by then.

 

 

Phil, Thank you for sharing the link, I'd not seen the Snow Scene before, make a nice Christmas Card!

[Pannier Tank]

On 28/03/2020 at 23:38, The Stationmaster said:

It seems all the discussion from the other thread is not yet transferred over so i'm holding fire until that happens.  Except to say  except to say that with a ground disc reading only one way through points back in those days it would be unlikely for it to be released by the FPL.  there is obviously a need for further discussion about the point lock bar.

 

The Ground Shunt Disc (Lever 10) was released by the Point (Lever 9) being Reversed. Lever 9 Reversed then Locked the FPL (Lever 11) Normal.

 

The GWSG - GWR Signalling Practice (P177) suggests that by the turn of the century the standard length for a Lock Bar was 50ft. It also suggests that the controlling signal, where possible was placed 30ft in the rear of the lock bar. This was to ensure that any train standing at the signal did not have any wheels on the Lock Bar preventing operation of the Facing point.

 

Looking at pictures of the Down Home Signal (Lever 12) and the Ground Disc Shunt Signal (Lever 10) and using the Track Gauge and height of the signal as a guide, I would judge this distance to be a lot less than 83ft.

Edited April 1, 2020 by Pannier Tank
Changed "Trailing" to "Facing"

[RailWest]

3 hours ago, Pannier Tank said:

 

The GWSG - GWR Signalling Practice (P177) suggests that by the turn of the century the standard length for a Lock Bar was 50ft. It also suggests that the controlling signal, where possible was placed 30ft in the rear of the lock bar. This was to ensure that any train standing at the signal did not have any wheels on the Lock Bar preventing operation of the trailing point.

 

 

Did not they/you mean 'facing'?

 

I find this statement rather puzzling. If the signal is at danger than no part of the leading engine should be in advance of the post, so the front wheel of the engine should be some way in rear of the signal. Admittedly they may not have be quite so 'strict' about a SPAD by the odd foot or so in those days, but even so a 30' tolerance seems a bit OTT.

 

Edited April 1, 2020 by RailWest

[Pannier Tank]

13 minutes ago, RailWest said:

Did not they/you mean 'facing'?

 

You are of course quite correct; I've changed the wording in my original message.

[Pannier Tank]

36 minutes ago, RailWest said:

Did not they/you mean 'facing'?

 

I find this statement rather puzzling. If the signal is at danger than no part of the leading engine should be in advance of the post, so the front wheel of the engine should be some way in rear of the signal. Admittedly they may not have be quite so 'strict' about a SPAD by the odd foot or so in those days, but even so a 30' tolerance seems a bit OTT.

 

 

It does say "that the controlling signal, where possible was placed 30ft in the rear of the lock bar."

 

In your opinion, what do you think the figure should be?

[The Stationmaster]

16 minutes ago, Pannier Tank said:

 

It does say "that the controlling signal, where possible was placed 30ft in the rear of the lock bar."

 

In your opinion, what do you think the figure should be?

It does seem a bit odd in view of the number of signals which were far closer to the point toe.   Clearly the idea of the 30 ft was to avoid wherever possible the use of lock bars through the switches because of their added complexities especially when the points bolted both way.  But equally a 30ft lock bar would have been inadequate for quite a number of the GWR's passenger vehicles so why not make the distance consistent with the minimum usual length of the bogie vehicles' inner wheelbase?   

 

But the comment in respect of a trailing point makes a lot more sense in relation to the use of a 30ft minimum  - so has there been a confusion somewhere between fouling bars and lock(ing) bars?

[Pannier Tank]

5 minutes ago, The Stationmaster said:

It does seem a bit odd in view of the number of signals which were far closer to the point toe.   Clearly the idea of the 30 ft was to avoid wherever possible the use of lock bars through the switches because of their added complexities especially when the points bolted both way.  But equally a 30ft lock bar would have been inadequate for quite a number of the GWR's passenger vehicles so why not make the distance consistent with the minimum usual length of the bogie vehicles' inner wheelbase?   

 

But the comment in respect of a trailing point makes a lot more sense in relation to the use of a 30ft minimum  - so has there been a confusion somewhere between fouling bars and lock(ing) bars?

 

The 30ft refers to the distance of the Controlling Signal in the rear of Lock Bar. The Lock Bar Length was quoted as being 50ft. 

 

[RailWest]

2 hours ago, Pannier Tank said:

 

The 30ft refers to the distance of the Controlling Signal in the rear of Lock Bar. The Lock Bar Length was quoted as being 50ft. 

 

But the length of the lock bar is irrelevant to the issue of why there was an additional distance between the end of the lock bar and the signal.

I would agree with Stationmaster that the information would make a lot more sense in terms of a signal that was in rear of a trailing point that was linked with a fouling bar.

 

[Pannier Tank]

2 hours ago, RailWest said:

But the length of the lock bar is irrelevant to the issue of why there was an additional distance between the end of the lock bar and the signal.

I would agree with Stationmaster that the information would make a lot more sense in terms of a signal that was in rear of a trailing point that was linked with a fouling bar.

 

 

Well, I only mentioned the Lock Bar because Mike mentioned it here.

 

On 28/03/2020 at 23:38, The Stationmaster said:

Except to say  except to say that with a ground disc reading only one way through points back in those days it would be unlikely for it to be released by the FPL.  there is obviously a need for further discussion about the point lock bar.

 

 

I quoted the dimensions to show that

 

9 hours ago, Pannier Tank said:

Looking at pictures of the Down Home Signal (Lever 12) and the Ground Disc Shunt Signal (Lever 10) and using the Track Gauge and height of the signal as a guide, I would judge this distance to be a lot less than 83ft.

 

which brings us nicely onto to the subject of what is actually located  between the Two Signals with regards the Point Lock Bar and what was the distance between the two signals?

 

 

Edited April 1, 2020 by Pannier Tank
correcting spelling mistake.

[Pannier Tank]

17 hours ago, RailWest said:

But the length of the lock bar is irrelevant to the issue of why there was an additional distance between the end of the lock bar and the signal.

My original message:-

 

 

My last bit of text is correcting Mike where he said a "30ft lock bar" I said The Lock Bar Length was quoted as being 50ft i.e not the 30ft Mike quoted.

Edited April 2, 2020 by Pannier Tank

[bécasse]

Surely the Moretonhampstead branch saw 70 foot auto trailers, for which the locking bars would have to be a minimum of around 60 foot long.

[Harlequin]

Lieutenant Seagoon, you say the walls of Sebastopol are 20ft thick?

Why do you say they are 20ft thick?

Have you ever measured the walls of Sebastopol?

They might, in fact, be only 10ft 6in thick.

What happened to the other 9ft 6in?

Lieutenant, are you blaming me for the war?

 

 

[Grovenor]

1 hour ago, bécasse said:

Surely the Moretonhampstead branch saw 70 foot auto trailers, for which the locking bars would have to be a minimum of around 60 foot long.

I would think a 50ft lockbar would be enough, most other lines only had up to 45ft. The lockbar only has to span between the bogies so at least one axle is on it, I'm sure the inner bogie axles were over 10ft from the coach ends.

[The Stationmaster]

13 hours ago, Grovenor said:

I would think a 50ft lockbar would be enough, most other lines only had up to 45ft. The lockbar only has to span between the bogies so at least one axle is on it, I'm sure the inner bogie axles were over 10ft from the coach ends.

According to something I read years ago it stated that because of their use of 70ft vehicles the GWR started using 60ft lock bars.  I know it was a secondary source and at present I can't get at any vehicle drawings as the books are currently inaccessible  but the maximum distance between wheels on a GWR 70ft vehicle wasn't much different from 50ft and possibly a bit over that distance (depending on bogie position and wheelbase).   As a lock bar is ineffective if it isn't as long as the maximum distance between any pair of vehicle wheels there does seem to be some grounds to think that the GWR might have used bars longer than 50ft in certain locations.

 

A running signal. should obviously normally be immediately in rear of the end of the lock bar however the photo shown in the Moretonhampstead thread could be seen as showing the signal further back than that, for whatever reason. 

[Pannier Tank]

In the absence of any official Mortonhampstead specific Operating Instructions, it is my view (others are entitled to theirs of course) that due to the short distance (nn ft ?) between the two signals, the Ground Shunt Signal (Lever 10) and the Down-Home Signal (Lever 12) would have been treated as if they were co-located. It would have been operationally difficult to treat the Signals as not co-located.

 

It would be particularly difficult for a mainly (if not entirely) loose-coupled goods train, having pulled forward from the Platform Road, having to stop with the rear of the train, in the rear of the Shunt Signal (10) but in advance of the Down-Home Signal (12) as has been suggested.

 

During the above shunting move, the Guard would make sure the rear of the train was clear of the Facing Point (Lever 9) before raising both hands to inform the Driver to stop. Due to the momentum and inertia of the train, the likelihood is, that the whole of the train could come to a stand in the rear of Down-Home Signal (12).

 

For operational purposes, the Down-Home Signal (Lever 12)  and the Ground Shunt Disc Signal (Lever 10) would have been treated as if they were physically co-located and that the Down-Home Signal would be  (for the want of a better description) a ‘marker point’ at which to ‘Marshall’ behind, therefore there would be no distinction between an hypothetical ‘Light Engine’ and the ‘Local Goods Train’ as regards access to the ‘Loop’ (they are both shunting moves, controlled by the Ground Shunt Signal). The driver in both scenarios would be authorised to proceed passed Signal 12 in the ‘on’ position, with the Signalman granting permission to proceed, by ‘setting the road’ and ‘pulling off Signal 10’.

 

Treating the Signals as co-located would also remove the anomaly of a Light Engine standing in the rear of the Down-Home Signal and requiring access to the Loop having to seek the Signalman’s authorisation to proceed pass the Down-Home Signal (12) at Danger even though the Signalman as already given his permission by pulling off Shunt Signal (10) yet a Driver shunting the Goods Train with his engine and part (or all) of his train in the rear of Down-Home Signal (12) being able to pass the Home Signal whilst at danger.

 

Can you imagine the conversation if the Driver of a Light Engine standing in the rear of Down-Home Signal (12) with the Road Set to the Loop and Signal 10 cleared,  walks to the Signal Box to seek the signalman’s permission to proceed?

[RailWest]

1 hour ago, The Stationmaster said:

A running signal. should obviously normally be immediately in rear of the end of the lock bar however the photo shown in the Moretonhampstead thread could be seen as showing the signal further back than that, for whatever reason. 

 

My untrained eye suggests that the Down Home post is about 5 sleepers back from the Bovey end of the lock bar.

 

The signal in the photo (which appears not to have migrated to this thread?) has a concrete post. IMHO it would be reasonable to assume that it was a later replacement for an earlier wooden post.

 

On that basis, let us assume that the previous signal was closer to the Bovey end of the lock bar. If the replacement concrete post had been installed in advance of its predecessor, then it might well have been located part the way along the lock bar, which could cause problems, and I doubt that the GWR would have wanted to shorten the bar. Consequently the new post was erected on the Bovey side of the old one, a bit further out from the end of the lock bar, hence the gap - which again the GWR probably never bothered to close by fitting a longer bar.

[The Stationmaster]

3 hours ago, Pannier Tank said:

In the absence of any official Mortonhampstead specific Operating Instructions, it is my view (others are entitled to theirs of course) that due to the short distance (nn ft ?) between the two signals, the Ground Shunt Signal (Lever 10) and the Down-Home Signal (Lever 12) would have been treated as if they were co-located. It would have been operationally difficult to treat the Signals as not co-located.

 

It would be particularly difficult for a mainly (if not entirely) loose-coupled goods train, having pulled forward from the Platform Road, having to stop with the rear of the train, in the rear of the Shunt Signal (10) but in advance of the Down-Home Signal (12) as has been suggested.

 

During the above shunting move, the Guard would make sure the rear of the train was clear of the Facing Point (Lever 9) before raising both hands to inform the Driver to stop. Due to the momentum and inertia of the train, the likelihood is, that the whole of the train could come to a stand in the rear of Down-Home Signal (12).

 

For operational purposes, the Down-Home Signal (Lever 12)  and the Ground Shunt Disc Signal (Lever 10) would have been treated as if they were physically co-located and that the Down-Home Signal would be  (for the want of a better description) a ‘marker point’ at which to ‘Marshall’ behind, therefore there would be no distinction between an hypothetical ‘Light Engine’ and the ‘Local Goods Train’ as regards access to the ‘Loop’ (they are both shunting moves, controlled by the Ground Shunt Signal). The driver in both scenarios would be authorised to proceed passed Signal 12 in the ‘on’ position, with the Signalman granting permission to proceed, by ‘setting the road’ and ‘pulling off Signal 10’.

 

Treating the Signals as co-located would also remove the anomaly of a Light Engine standing in the rear of the Down-Home Signal and requiring access to the Loop having to seek the Signalman’s authorisation to proceed pass the Down-Home Signal (12) at Danger even though the Signalman as already given his permission by pulling off Shunt Signal (10) yet a Driver shunting the Goods Train with his engine and part (or all) of his train in the rear of Down-Home Signal (12) being able to pass the Home Signal whilst at danger.

 

Can you imagine the conversation if the Driver of a Light Engine standing in the rear of Down-Home Signal (12) with the Road Set to the Loop and Signal 10 cleared,  walks to the Signal Box to seek the signalman’s permission to proceed?

No need for any written Instructions - the blokes doing the work would have been doing it for years learning the ropes from those who had been doing it for years before they started on the job.

 

A shunt move would no doubt draw back as far as was necessary. with the person i/c the shunting also allowing for any rebound with a rough, sorry 'enthusiastic', Driver.  As far as which signal they took notice of the answer is simple - an arriving train, of whatever sort, was controlled  by the running signal, the points would be set towards the platform and would be locked by the FPL because that was what the regulations required for a train to be accepted.  And it would be relatively easy for anyone just looking at the Train Register Book at a later date to pick up if something 'a little odd' was being done.

 

On the other hand the disc applied to shunting movements towards the loop and sidings - end of story because that was what it was there for.   In other words it was little different from numerous other places on the GWR where it might be construed that a running signal was being passed at danger whereas in fact the movement was being controlled. by a ground disc in advance of that running signal.  In later years the approach was to co-locate the two signals but in reality it all depends on what the signals were there for.    A shunt move back into the platform might have been handsignalled but equally could quite legitimately be signalled using the Home Signal.  I would imagine that for speed the normal behaviour was simply to swing the point and for the person i/c shunting to give the Driver a handsignal  - I;'ve never yet come across anyone who doesn't take shortcuts with moves like that except (but not always) when officialdom is lurking nearby.

[Pannier Tank]

Mike, thank you very much for your valued reply.

 

You may recall that this latest discussion started with the following question being asked and my subsequent reply.:-

 

Happy Hippo said “As a matter of interest, I am presuming that a loco stopped at the down home but wanting to access the loop, would require both the down home and the loop disc to both be cleared before proceeding.”

 

 

I don’t have any issues with the Shunting operation of the Goods Train, it’s how the “Light Engine” is dealt with when standing at the Down-Home Signal requiring access to the Loop that I have issues.

 

I can understand that the regulations would require the Facing Point to be Set for the Platform Road and the FPL is to be engaged before accepting the Light Engine.

 

Would the Regulations also require that the Down-Home Signal to be lowered as well?

 

It has been suggested that the Driver of the Light Engine standing at the Home-Signal would require permission from the Signalman to pass the Down-Home Signal set to Danger.

 

If the concern is that the Driver is passing the Down-Home Signal at Danger, my view is that the Signalman would give his permission by setting the road and pulling the Shunt Signal ‘off’. 

 

This controlled move is completely different to an uncontrolled move by the Driver passing the Signal set to Danger without any road being set.

Edited April 2, 2020 by Pannier Tank

[The Stationmaster]

40 minutes ago, Pannier Tank said:

Mike, thank you very much for your valued reply.

 

You may recall that this latest discussion started with the following question being asked and my subsequent reply.:-

 

Happy Hippo said “As a matter of interest, I am presuming that a loco stopped at the down home but wanting to access the loop, would require both the down home and the loop disc to both be cleared before proceeding.”

 

 

I don’t have any issues with the Shunting operation of the Goods Train, it’s how the “Light Engine” is dealt with when standing at the Down-Home Signal requiring access to the Loop that I have issues.

 

I can understand that the regulations would require the Facing Point to be Set for the Platform Road and the FPL is to be engaged before accepting the Light Engine.

 

Would the Regulations also require that the Down-Home Signal to be lowered as well?

 

It has been suggested that the Driver of the Light Engine standing at the Home-Signal would require permission from the Signalman to pass the Down-Home Signal set to Danger.

 

If the concern is that the Driver is passing the Down-Home Signal at Danger, my view is that the Signalman would give his permission by setting the road and pulling the Shunt Signal ‘off’. 

 

This controlled move is completely different to an uncontrolled move by the Driver passing the Signal set to Danger without any road being set.

The question here is really how often did that actually happen?   Basically there was no signalled move from the Home Signal to the Loop, there was only a shunting move from the ground disc.   the only way such a move could be done is taht after the engine arrived and came to a stand at the Home Signal the FPL could be unbolted and the points reversed and technically the driver should be given a handsignal to pass the Home Signal at Danger due to the two signals not being co-located.  No doubt what would happen in practice is that the disc would be lowered and the engine would then go into the loop duly ignoring the Home Signal.

 

Interestingly in both the 1938 and 1947 Service Timetables there were no light engine movements booked on the branch although that obviously doesn't mean that there weren't any although there was no apparent reason for them judging by the booked service.  Similarly I can't readily envisage any need to changeover the branch engine as an extra movement as this could easily be done at Newton during the normal working day.  So I can't really see much need for it to happen and it would only happen if a light engine arrived from Newton Abbot.  If it was an engine off the Newton end of a push-pull train it would of course have been a shunt move