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Pannier Tank

Moretonhampstead Signalling

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For a number of Years, I have been looking at building an EM Gauge Layout based on Moretonhampstead BR(W).

 

I have Developed an Arduino Based Signal Interlocking System based on RMweb Member ffayolle (Fabrice) thread as shown here:

https://www.rmweb.co.uk/community/index.php?/topic/82978-arduino-applications-and-programs/page/4/&tab=comments#comment-2276967

 

 

The Signal Interlocking System consists of an Arduino MEGA and a MCP2515 CANBUS Module which communicates with the MERG CBUS System to control Signals and Points.

 

Phase 1 is a Control Panel with 12 Switches, 12 Output LEDs and 12 Lock LEDs. The Lock LEDs show which Lever is “Locked”. If a “Locked” Lever is moved, the Lock LED will “Flash” to show an incorrect Lever Movement. The Output LEDs will only Light up for a valid move. The status of “Outputs” and “Locks” are sent to the MERG CBUS to operate the appropriate Signals and Points.

 

A brief video of the Signalling Panel is shown here: https://www.youtube.com/watch?v=w9k7PS-KxTo

 

 

Having followed Sigtech’s Thread on Sproston Signalling  https://www.rmweb.co.uk/community/index.php?/topic/149590-sproston-signalling-alterations/page/2/ and following subsequent conversations with Phil, RMweb Member Harlequin; Phil has produced a pre 1930s Style Signalling Diagrams for Moretonhampstead produced here for comments.

 

Pre 1930s

 

image.png.d2de066d15ac5c1fa86c2db1c18b6c36.png

 

There are a couple of questions I would like to ask:

 

1:  The Size of Moretonhampstead Lever Frame, was it 12 Levers or 15 Levers with 13,15    & 15   not used?

 

2:  Are the “Traps” drawn correctly in either version?

 

image.png

Edited by Pannier Tank
Post 1930s Style Diagram removed as the Pre 1930s Style Diagram was likely to have survived to the end.
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Traps are correct in both versions.  According to the 1919 Locking Chart on the SRS site the second frame only had 12 levers with no spares or spaces (until No.3 became spare when the Shunt Ahead subsidiary was removed in 1954).

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Hello Mike,

 

Thank you for your reply, much appreciated.

 

Another question I should have asked is which version of the Signal Diagrams would be appropriate for the British Railways era?  i.e Would the 1930s Diagram have been in place up until closure in 1959 or would it have been replaced at Nationalisation or when the Shunt Ahead Signal was removed in 1950s?

 

 

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Very nice graphics on the diagram, small point but the sticker " this diagram must not be removed" I've always seen in the bottom right of the diagram. As here on Radstock South. I suppose there could be exceptions ...

 

527663494_RadstockSouthDiagram.jpg.f1b70a008be55351bb08f3e2bee87f86.jpg

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22 minutes ago, Tim V said:

Very nice graphics on the diagram, small point but the sticker " this diagram must not be removed" I've always seen in the bottom right of the diagram. As here on Radstock South. I suppose there could be exceptions ...

 

527663494_RadstockSouthDiagram.jpg.f1b70a008be55351bb08f3e2bee87f86.jpg

 

Thanks Tim,

 

"GWR Signalling Practice" by Smith and the Great Western Study Group, says the label should be , "in one of the bottom corners".

 

I guess that bottom right was preferred but if there wasn't room because of the drawing (as in this case) it would be fixed at bottom left. I should maybe move it further left, though.

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Should not a pre-1930s version have a red distant 'fixed at danger'?

 

Would the later version actually have the signal-box labelled as such?

 

Might not it be the case that they simply amended the old diagram to remove No 3, but otherwise left it 'as was'?

 

By a curious coincidence I drew an imagined 1/2-size version back in the 1970s when I was researching the site - still have it somewhere - the potential for a model of the planned extension to Chagford occupied my attention for a while :-)

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Looking at both diagrams I felt that the whole arrangement of 9,10,11,12 seemed a bit messy so I looked up Pryer. He states box was reframed c1920 so I think the SRS is probably near enough, going from 15 levers to 12. What I hadn't realised is that 9B points had a one hole FPL so the pull sequence is either 9, 10 or 11,12, BTW did the GWR differentiate point ends worked from the same lever, I think A,B is a BR thing. It would seem likely that a new diagram was provided with the new frame. From a cartographic point of view disc 10 should be the other side of 12.

Regards

Martin

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2 hours ago, RailWest said:

Should not a pre-1930s version have a red distant 'fixed at danger'?

Yes, possibly.

 

Quote

 

Would the later version actually have the signal-box labelled as such?

I think the later version would but conversely possibly not the earlier style?

 

Quote

 

Might not it be the case that they simply amended the old diagram to remove No 3, but otherwise left it 'as was'?

Yes, that's the route we will probably go down. It's PT's decision.

 

Quote

 

By a curious coincidence I drew an imagined 1/2-size version back in the 1970s when I was researching the site - still have it somewhere - the potential for a model of the planned extension to Chagford occupied my attention for a while :-)

Sounds interesting!

 

1 hour ago, Martin Shaw said:

Looking at both diagrams I felt that the whole arrangement of 9,10,11,12 seemed a bit messy so I looked up Pryer. He states box was reframed c1920 so I think the SRS is probably near enough, going from 15 levers to 12. What I hadn't realised is that 9B points had a one hole FPL so the pull sequence is either 9, 10 or 11,12, BTW did the GWR differentiate point ends worked from the same lever, I think A,B is a BR thing. It would seem likely that a new diagram was provided with the new frame. From a cartographic point of view disc 10 should be the other side of 12.

Regards

Martin

Thanks yes, we also found reference to the 15-lever frame being replaced in 1920. So for PT's period we can ignore the earlier frame entirely now. 12 levers only.

The AB suffixes are on the 1950's style BR(WR) diagram, which we will probably not use now.

Good point about 10 and 12. That will be fixed, thanks.

 

Edited by Harlequin

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4 hours ago, Pannier Tank said:

Hello Mike,

 

Thank you for your reply, much appreciated.

 

Another question I should have asked is which version of the Signal Diagrams would be appropriate for the British Railways era?  i.e Would the 1930s Diagram have been in place up until closure in 1959 or would it have been replaced at Nationalisation or when the Shunt Ahead Signal was removed in 1950s?

 

 

All that would have happened - judging by many other diagrams I have seen altered in this way - is that the Shunt Ahead would have been 'scratched' off the signal box linen copy.  Nobody would bother with a new diagram for such a minor change.  I have seen numerous diagrams (and in fact own one) where far more than a signal arm has been removed/obliterated in such a manner including complete sidings.  In some cases bigger alterations - such as on another diagram I own - a removed line and point etc would simply be carefully covered over by an additional piece of linen - which was not necessarily pasted to the original diagram. 

1 hour ago, Martin Shaw said:

Looking at both diagrams I felt that the whole arrangement of 9,10,11,12 seemed a bit messy so I looked up Pryer. He states box was reframed c1920 so I think the SRS is probably near enough, going from 15 levers to 12. What I hadn't realised is that 9B points had a one hole FPL so the pull sequence is either 9, 10 or 11,12, BTW did the GWR differentiate point ends worked from the same lever, I think A,B is a BR thing. It would seem likely that a new diagram was provided with the new frame. From a cartographic point of view disc 10 should be the other side of 12.

Regards

Martin

I have found with various dagrams that the SRS diagrams and George Pryer's precisely match each other.  This is probably a result of George being the original 'box diagram draughtsman for the SRS!

 

The position of disc 10 on the diagram should match the way it was placed on the ground so it needs really to be matched to a photo (maybe it was?).  As the disc needed to be detected by the points I presume it wouldn't have been too far out of line with the detector position.   I'm not sure without checking some originals of the extent to which A & B ends were differentiated on differeent diagrams. but as seen above they definitely weren't shown on the earlier style where the point number was within the circle.

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There is a 1955 photo on p155 of Owen's book on the line, taken from  a short distance in rear of the Down Home and looking towards the station. Allowing for the angle of view, IMHO disc 10 is right in line with the toe end of the switch blade of 9B, whereas the DH (on a concrete post) is set further back by (at least) the length of the FPL's lock bar (which can be seen inside the Up side rail).

 

Also (see p151) the overall roof extended almost to the top of the platform ramp at the town end, about half-way along crossover 5.

Edited by RailWest
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Here is an updated version of the 1920 box diagram for the 12 lever frame, later modified by the removal of the shunt ahead signal and the closure of Lustleigh box:

958090511_PTMH4.png.965b55536679ae7fdd3a2976f8a0cd08.png

 

I've also made various other tweaks thanks to everyone's suggestions above. (I haven't changed "Caution" to "Danger" because I found a period example using "Caution".)

 

Question: Would the occupation crossing have been shown on the box diagram in some form?

 

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It looks very nice, but....just to be pernickity :-) I would suggest that 'Spare levers' would be just 'Spare' and in the singular only.

 

Also, do we know if 3 was left as a spare or taken out  and left as a space? If left as a spare then in fact it might have been marked as a Temporary Spare Bolted Normal.

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Thank you all for your contributions to this thread, many questions answered. Also thanks to Phil for making  the alterations to the diagram.

 

Now that Phil has moved "Shunt Signal 10" to the Toe of "Point 9 "it reminds me of a photograph which shows that Shunt Signal 10 is a few yards in advance of the Down Home Signal. Would the Shunt Signal have had a "White or Red Lens" for "Stop"?

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The relative displacement of 10 after 12 raises a potential issue. Does 10 precede 12 in the locking, if not then in theory 12 cleared leads to a stop signal 60 feet or so on. I realise custom and practice in the 1950s may well override modern considerations, but does anyone know if the locking table exists?

Regards

Martin

Edited by Martin Shaw
grammar

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31 minutes ago, Martin Shaw said:

The relative displacement of 10 after 12 raises a potential issue. Does 10 precede 12 in the locking, if not then in theory 12 cleared leads to a stop signal 60 feet or so on. I realise custom and practice in the 1950s may well override modern considerations, but does anyone know if the locking table exists?

Regards

Martin

 

Hence my query, did the Shunting Signal 10 have a Red or White Lens?

 

Mortonhampstead Locking Table

 

https://www.s-r-s.org.uk/html/gwe/S906-3.pdf

 

 

Edited by Pannier Tank
Title
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Thanks PT, I note that 10 and 12 are effectively selected by the position of 9, so your question is a very good one. I don't know enough about GWR/WR practice and whilst I have the recent book I have by no means read enough of it to have an opinion.

Regards

Martin

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8 hours ago, Pannier Tank said:

Thank you all for your contributions to this thread, many questions answered. Also thanks to Phil for making  the alterations to the diagram.

 

Now that Phil has moved "Shunt Signal 10" to the Toe of "Point 9 "it reminds me of a photograph which shows that Shunt Signal 10 is a few yards in advance of the Down Home Signal. Would the Shunt Signal have had a "White or Red Lens" for "Stop"?

Technically it should have shown a white light as it was released by 9 so therefore could not be cleared for a train running to the platform.  As such it should not be confused with a leading disc which it very definitely was not - it was there solely for shunting purposes - and because the Home signal locked the points which released the disc it could hardly be there for any other reason.

 

What this does do of course is take us to the way some modellers work terminus layouts as opposed to the way they were laid out and signalled to be worked,  A freight train would terminate in the platform line and be shunted from there - thus once the engine had run round it would be shunting to the various sidings and the loop using that signal.  Some modellers seem to work under the impression that arriving freight trains ran into the loop line rather than the platform - well in some cases they did but usually that was at places where the layout was signalled, for whatever reason, to allow that to happen (and the loop at Moretonhampstead very clearly wasn't signalled in that way).  And of course there is an obvious reason why the platform line was used at most places - it normally offered the longest length of run round.  Apart from the fact that if the platform line was occupied by a train or vehicles the Block Regulations wouldn't allow a second train to be accepted unless the layout was signalled to permit it.

 

(And before anybody quotes it Ashburton was an oddity with what amounted to its own Regulations which were basically those which the South Devon Railway had introduced when the line was opened.) 

 

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Posted (edited)

Happy New Year everyone.

 

12 hours ago, The Stationmaster said:

Technically it should have shown a white light as it was released by 9 so therefore could not be cleared for a train running to the platform.

 

I thought that might be the case.

 

12 hours ago, The Stationmaster said:

A freight train would terminate in the platform line and be shunted from there - thus once the engine had run round it would be shunting to the various sidings and the loop using that signal.

 

This is how I intend to operate the Layout. 

Edited by Pannier Tank
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12 hours ago, The Stationmaster said:

Apart from the fact that if the platform line was occupied by a train or vehicles the Block Regulations wouldn't allow a second train to be accepted unless the layout was signalled to permit it.

 

The Platform Road had to be kept clear for an Auto-Train which arrived 13:21 and departed 13:35 whilst the Goods Train was at Moretonhampstead. The Goods Train departed Moretonhampstead at 13:51.

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1 hour ago, Pannier Tank said:

 

The Platform Road had to be kept clear for an Auto-Train which arrived 13:21 and departed 13:35 whilst the Goods Train was at Moretonhampstead. The Goods Train departed Moretonhampstead at 13:51.

Yes but the goods would have been shunted to the loop by then to allow the auto to be accepted.  Very easy on a model railway to forget that you need to get the Clearing Point clear in time for the train to be accepted from the signal box in rear, which could be several miles away, and not just before it appears on the modelled scene.  We obviously compress time when operating model railways but there still needs to be a believable interval when a train is going to approach.

 

And of course nothing at all wrong, if needed, with the goods making some more shunts after the auto train has arrived in the platform and finishing in time for the auto to leave.

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55 minutes ago, The Stationmaster said:

Yes but the goods would have been shunted to the loop by then to allow the auto to be accepted.  

 

Indeed, I would imagine that once the loco had run-round it would move the train into the Loop / Goods Yard ready for Shunting. I've seen a photograph of the return working waiting in the Goods Shed Road waiting for departure time.

 

All very interesting; the Operations and Signalling of Moretonhampstead is one of the reasons I chose this particular location.

 

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David,

It sounds great...

And I like your graphic

Fabrice

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On 02/01/2020 at 13:00, ffayolle said:

It sounds great...

 

Thank you for allowing me to use your original code and helping with adapting the code for use on Moretonhampstead.

 

On 02/01/2020 at 13:00, ffayolle said:

And I like your graphic

 

Phil (Harlequin) has done a grand job with the Diagram.

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I got some SRS publications today including No. 8 “Signal box diagrams of the GWR”. Thanks to whoever suggested them!

 

Some reading to do tonight!

 

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

1839565959_PTMH7.png.a9e5664283ca030caccbdfa2ab26d0b5.png

 

The signal and ground disc symbols have been changed to be more correct for the period.

Colours revised to match the period colours better (but there's still some work to do on that).

Lots of detail changes.

1786755071_PTMH7detail.png.bc919205e3268a83421e87876547fd09.png

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