Point rodding and signal wires

[The Stationmaster]

However sometimes preservation type folk, such as the ones who planned this, haven't learned the lesson!

 

 

But you don't even need to be next to stop block to demolish a signal box = a partially derailed stone train from Westbury to Theale in 1971 did a very comprehensive job on the timber built 'box at Hungerford leaving Relief Signalman Bob Bowden clinging to the back wall of the 'box until the Fire Brigade could rescue him about 30 minutes later.  Bob had good head of fairly long black hair back then but a couple of days later all his hair turned white although it gradually reverted to its natural colour and was back to normal when I again came into regular working contact with him in the very late 1970s/early '80s,

 

Another lineside timber 'box which suffered from the ravages of a derailed stone train was Clink Road jcn although there it was what appeared to be no more than a Reasonably harmless side swipe which partoially took out one corner post.  But from that day onwards every time an Up train passed at speed the entire ;'box flexed as the front left hand corner seemed to drop and then come back up after the train had passed.

[The Stationmaster]

5 hours ago, 5BarVT said:

And since, the brick built location at the Up end of Ruscombe Goods loop succumbed in a similar way in the early 70s.

Paul.

With spectacular results in terms of train delays.  although described as a relay room the structure reportedly only contained a lot of  cable jointing but it still took out the signals and SPTs over at least 5 route miles plus destroying all communication between Reading (or possibly still Twyford at that time?) and Slough panels.

[RailWest]

11 minutes ago, The Stationmaster said:

However sometimes preservation type folk, such as the ones who planned this, haven't learned the lesson!

 

 

 

Not visible in the photo is the trap-point at the end of the Up Loop a short distance to the left of the box. IIRC the locking (or the Local Instructions?) required the trap to be closed before the Up Home can be lowered, apparently specifically in order to prevent an over-running incoming train from demolishing the box! Allegedly the risk of it running head-on into a train standing at the Down Home was considered less severe :-)  Mike may be able to add more....?

[The Stationmaster]

I didn't look at the 'box Instructions when i was there but I would think the biggest risk of a train coming off at that trap would it be landing in the Old Mill Leat having first demolished the telegraph pole, the bridge (over the leat) handrails and probably part of the low stone parapet as well.

 

The trap appears to be there more for when the loop is used as a siding rather than when it is used to cross trains.  If the trap is closed before the signal is lowered it's basically no different from any other single line crossing loop which doesn't have trap points.

 

[Nick C]

We have a similar setup at Alton, with a loop with a trap point on the exit, and the same requirement, the exit points must be set for the loop before a train can be admitted by the running signal at the other end. There's also a set of buffer stops next to the 'box wall too, but that's the trap from the Network Rail access, so it'd need one of SWR's EMUs to SPAD by over 100m to hit them...

[Phil Bullock]

15 hours ago, TheSignalEngineer said:

About 12 years later c1970 I was travelling to Worcester on the first train out of Birmingham and we were talked by Kidderminster Station's Home signal into the platform. When we got there a coal wagon was buried in the end wall of the box nearest to the Goods shed.

And not the first time that box was taken out …. According to Tony Barfield the original was completely demolished when a passing fitted freight derailed.

 

The Abbotswood box is at the top of a climb …. Albeit prototypically not too steep …. In both directions. It was at the end of an engineers siding on the prototype but we have made that in to a goods loop for increased operating flexibility. Going to experiment with a DCC Asymmetric braking section in advance of and interlocked with the exit starter signals so the scope to demolish the box on the model should be minimised…. Hopefully 

[RailWest]

1 hour ago, Nick C said:

We have a similar setup at Alton, with a loop with a trap point on the exit, and the same requirement, the exit points must be set for the loop before a train can be admitted by the running signal at the other end. There's also a set of buffer stops next to the 'box wall too, but that's the trap from the Network Rail access, so it'd need one of SWR's EMUs to SPAD by over 100m to hit them...

I was told that this was done to avoid expensive claims from the owners of visiting engines at the head of Up trains if they shot off the end and down the side of a 30-odd foot embankment :-)

[TheSignalEngineer]

2 hours ago, Phil Bullock said:

And not the first time that box was taken out …. According to Tony Barfield the original was completely demolished when a passing fitted freight derailed.

Wasn't that the Junction around 1953?

[Phil Bullock]

13 hours ago, TheSignalEngineer said:

Wasn't that the Junction around 1953?

Ah yes! The replacement looked pretty unsubstantial timber built….

 

So back to rodding ….. compensation cranks. Every run should have one….. but should a single run driving a crossover at both ends have two? One between the bed and the take off to the first switch, and the second between the two take offs to reverse the throw? 
 

Cheers

[bécasse]

2 hours ago, Phil Bullock said:

So back to rodding ….. compensation cranks. Every run should have one….. but should a single run driving a crossover at both ends have two? One between the bed and the take off to the first switch, and the second between the two take offs to reverse the throw? 

Yes, and the same principle would generally apply if a single lever worked more than one FPL.

[The Stationmaster]

4 hours ago, Phil Bullock said:

Ah yes! The replacement looked pretty unsubstantial timber built….

 

So back to rodding ….. compensation cranks. Every run should have one….. but should a single run driving a crossover at both ends have two? One between the bed and the take off to the first switch, and the second between the two take offs to reverse the throw? 
 

Cheers

Not necessarily.  A rodding run should be designed to more or less equalise the length of pull and push in the run.  If that has been equalised before the first point end it works, or the rodding runs only in a single direction but that is less than 10 yards (the old figure - it might have changed?) there is no need for a compensator in that stretch of the rodding run.  But there does have to be a compensator between the two end of a crossover worked off the same lever.

[TheSignalEngineer]

4 hours ago, Phil Bullock said:

So back to rodding ….. compensation cranks. Every run should have one….. but should a single run driving a crossover at both ends have two? One between the bed and the take off to the first switch, and the second between the two take offs to reverse the throw? 

Yes, and don't forget that the position is determined not only by distance but also if there is a change of action from pull to push at a crank in the run.

One of the lost attachments that has come back from the other side shows an example of how the rodding run is can be laid out. It was derived from what I could see on a photo posted in a question about a Midland location.

 

The IRSE has a file on the web in its Minor Railways section about mechanical points, including some drawings of compensation of rodding runs towards the end.

 

https://www.irse.org/Portals/0/NewPortal/DownloadableLinks/Get Involved/MinorRailwaysSection/PA01 - Mechanically Operated Points v2.pdf?ver=2019-09-12-130218-450

[Phil Bullock]

Many thanks gentlemen will plan accordingly 

 

Phil

[Phil Bullock]

2 hours ago, TheSignalEngineer said:

Yes, and don't forget that the position is determined not only by distance but also if there is a change of action from pull to push at a crank in the run.

One of the lost attachments that has come back from the other side shows an example of how the rodding run is can be laid out. It was derived from what I could see on a photo posted in a question about a Midland location.

 

The IRSE has a file on the web in its Minor Railways section about mechanical points, including some drawings of compensation of rodding runs towards the end.

 

https://www.irse.org/Portals/0/NewPortal/DownloadableLinks/Get Involved/MinorRailwaysSection/PA01 - Mechanically Operated Points v2.pdf?ver=2019-09-12-130218-450

That’s an excellent document many thanks. One question i could not see answered is would all runs have the same action on leaving the box ? Push or pull…. ? Was this standardised as the Abbotswood box had the frame at the back of the box.,,,,

Edited May 6, 2022 by Phil Bullock

[Nick Gough]

On 05/05/2022 at 11:54, RailWest said:

Not visible in the photo is the trap-point at the end of the Up Loop a short distance to the left of the box. IIRC the locking (or the Local Instructions?) required the trap to be closed before the Up Home can be lowered, apparently specifically in order to prevent an over-running incoming train from demolishing the box! Allegedly the risk of it running head-on into a train standing at the Down Home was considered less severe :-)  Mike may be able to add more....?

 

I notice, in this photo, that the right hand window, on the operating floor, appears to be painted over.

 

Would I be right in thinking this is because there is a wc behind it?

 

Was that standard practice on the GWR/WR?

[RailWest]

The toilet was at the other end, at the top of the stairs in the porch.

I  may be wrong, but I think this was done to avoid overlooking an adjacent house.

[The Stationmaster]

17 minutes ago, Nick Gough said:

 

I notice, in this photo, that the right hand window, on the operating floor, appears to be painted over.

 

Would I be right in thinking this is because there is a wc behind it?

 

Was that standard practice on the GWR/WR?

On the WR it was forbidden to paint over signal box windows unless it was done for official reasons - usually the top level of any glazing - to prevent stray artificial light coming in.   (Unlike some parts of the London area on the LMR where some very odd signal box window painting practices could be seen including one box on an ex GC line where almost the whole of the glazing was painted over leaving just a couple of clear 'letter box' size slits un painted - that was done by the resident Signalman.).

[Michael Hodgson]

1 hour ago, The Stationmaster said:

(Unlike some parts of the London area on the LMR where some very odd signal box window painting practices could be seen including one box on an ex GC line where almost the whole of the glazing was painted over leaving just a couple of clear 'letter box' size slits un painted - that was done by the resident Signalman.).

He must have been suffering difficulty sleeping on his night shifts!

[The Stationmaster]

21 minutes ago, Michael Hodgson said:

He must have been suffering difficulty sleeping on his night shifts!

From what was being said just over (what was at that time) the border with WR territory uyou have hit the nail on the head.  Around the time of taking over the WLL from the WR the LM decided to go in fora big recruitment drive in the London area and I think the main qualification for successful applicants was their ability to stand up.   judging by what was said in the 'box at Northolt Jcn one weekend when i was there - and by what I witnessed happening on the block bells and block instrument - the LM had recruited some right useless specimens.  The WR District Inspector I was with was appalled and immediately started trying to get hold of his LMR opposite number - who it later turned out seemed to be equally appalled but whose hands were tied - for various reasons I won't go into - when it came to dealing with the miscreant. (who I suspect had his Sunday afternoon nap disturbed by. a need to deal with trains),

[JRamsden]

I hope you don't mind me hijacking this thread for another point rodding question of my own?

 

I've been reading the thread with great interest as I am about to embark on my own point rodding journey and want to get it as accurate as possible. My layout is a very small branch terminus (trains enter from the right and the left is a very short head shunt) and I'm using the Wills point rodding kit. To be honest, the whole thing blows my mind a little, but I really want to add this level of detail.

 

Below is a diagram of my current thinking. The concrete area centre bottom of the photo is the site of an engine shed.

 

 

My main questions are:

 

1) Would the suggested path taken by the rods make sense/be permitted on the prototype? I see the most direct route would be to take most of the rods along the platform edge, but there's very little clearance for what would be 6 rods. What would happen in real life if the only viable route was very narrow?

 

2) 4 points are served by rodding (the last will be a lever frame as it belongs to a private siding) but do the remaining 4 points all need facing point locks?

 

3) Am I interpreting compensators correctly, or should there be more?

 

4) If anyone is feeling particularly kind... where would I need to add ground signals?

 

Thanks!

Jonathan

[RailWest]

Far too many unnecessary rods !

 

1. The only points which need to be operated by the signal-box would be those at each end of the run-round loop, including the trap-points at the ends of the loop which you have omitted :-)  All other (siding) points would be worked by adjacent hand-levers.

2. One rod from the SB alongside the platform to serve the point + trap at the LH end.

3. One rod out of the SB dividing into to two going in different directions to work the point and trap at the RH end.

4. Another rod from the SB to the FPL on the facing point at the RH end.

5 As regards ground-signals, at most one into and one out of the loop at the RH end and similar at the LH end.

6 Ideally your starting signal should be on the platform in rear of the point at the RH, otherwise any train standing at it fouls any moves in/out of the loop, but with your short layout that might look a bit odd.

 

It might be easier to deal with compensators after you've redrawn the rods :-)

[Michael Hodgson]

1 hour ago, RailWest said:

It might be easier to deal with compensators after you've redrawn the rods :-)

On the basis of the rodding drawn, it would be heavy to work, as there are a lot of cranks and one run crosses the line three lines.  These should be minimised.  Use cranks where unavoidable, but a single straight run is easier to operate.

Compensators would be placed not half way along the longest rod nor half way from box to points - they go half way along the total length of rodding run.  The compensator (a pair of cranks connected to each other) turns push of one half rod to pull of the other, and on the assumption (not always true if part of the run is in the shade) that the whole of the rodding expands the same amount as the temperature rises both halves expand towards the compesnator turning the two cranks slightly.

 

FPLs are only a reqirement if passenger trains run regularly over them, so the right hand point is the only one which would be so equipped.

 

[TheSignalEngineer]

2 hours ago, JRamsden said:

Below is a diagram of my current thinking. The concrete area centre bottom of the photo is the site of an engine shed.

First of all, you need some points to act as traps to protect the passenger line against unauthorised moves from the sidings. There is a set of points in the yard which could be worked from the box for this purpose. The left hand end will depend on the method of working.

There is a whole string of questions to consider starting with the company and era you are modelling. Will you have more than one loco on the layout at any one time?

It would also be helpful to have a complete plan of the layout and the moves you intend to make.

 

You may like to start a separate thread to look at the various options and decide the best way forward.

 

[JRamsden]

Many thanks folks @RailWest, @Michael Hodgson & @TheSignalEngineer Already this is a great help :)

 

I have started my own thread, as suggested.

[Phil Bullock]

Moving on to Abbotswood specific installation issues now…. Don’t want to hijack this thread so pop over to the Abbotswood and Norton Junction thread if you want to see what’s going on.