Point machines on an SR branch line

[Blandford1969]

Not sure this is relevant and Chris may well put me right it I am wrong, however I have a memory of one of the points at Stalbridge on the S&D having an electric point motor (takes cover) lol

[jim.snowdon]

Of interest

http://www.railwaysarchive.co.uk/documents/MoT_Sheerness1971.pdf

If nothing else, thank you for a reminder of the quality of the reports written by Her Majesty's Inspectors, which stand in distinct contrast to those of their successors.

 

Jim

[Mike Storey]

>>>You will notice that the centre road has GF operated crossovers at the stops ends, neither with an FPL. 1 for release and 2 and 3 for each pair of points. .....

 

Actually, if you look closely it has 4 levers. 1 is the release for 2, 4 is the release for 3. Think of it as two separate GFs - one for each platform - combined in one frame - with the appropriate interlocking between them.

 

>>>Whereas the GF operated junction at the left of the diagram, to release trains from the Westminster Straight (from the Dockyard), does include a FPL....

 

Which is what one would expect, given that it is a facing point on a passenger line :-)

 

You are of course correct about there being two releases, one per crossover pair.

 

But you have not spotted the contradiction - both the crossovers within the platforms become facing points to passenger trains, when they leave Sheerness, at least for the final car of the unit (or drawn vehicles, of which Sheerness had a fair number on charters). So why the FPL out at the Westminster Straight and not within the platforms? (cf the preceding debate in this thread). I can only surmise that speed is the factor. Despite trawling through signalling regs and GA's from around that period, I can see no specific explanation on the principle, other than a general reference to a need for FPL's "appropriate to the safe passage of passenger trains". I guess the variation allowed must have resided within the finer detail of signalling design principles, with which I am not familiar, as a non-engineer.

 

Perhaps a signalling engineer on here may have a more informed comment?

[TheSignalEngineer]

Not sure this is relevant and Chris may well put me right it I am wrong, however I have a memory of one of the points at Stalbridge on the S&D having an electric point motor (takes cover) lol

Correct, the points at the Templecombe end were too far from the box to be mechanically worked. I don't know the history, but either there would have had to be a second box or perhaps the loop was extended at some time?

[Mike Storey]

The unusual features at Sheerness are the trap points on the platform ends, what was the reason for those?

Regards

 

Standard BR (SR) practice in those days - Queenborough, Swale and Kemsley (Down) also had them, to protect movements onto the single line, where a safe diverging route was not possible. There were similar arrangements off the Grain branch at the Hoo end. 

 

You will note the middle road at Sheerness does not have a trap point but a form of derailer (splits both ways), as there is no safe "trap" to left or right. On my very first day alone, as an Assistant SM at Sittingbourne, after several weeks trailing behind one of the other two much more experienced ASM's, I had to deal with a freight derailed on that derailer. The usual move was for the loco to propel the train in reverse from the middle road back on to the single line and then into Sheerness Steel's sidings. The move was controlled by the dummy at the Sittingbourne end, which was hard to see for the driver. The train was a set of MCV's and a Class 73. I cannot recall whether there was a guard or a second man, who was supposed to operate the ground frame and then proceed to the far end to give handsignals to the driver when the dummy was cleared. An Area Inspector soon turned up behind me to take over investigation of the cause whilst I dealt with trying to get services running again (the end vehicle was tilted at about 30 degrees towards the road from Platform 1, and we had a passenger train stuck there.) We inched the EMU out of the platform with our hearts in our mouths, and then awaited the CM&EE crew from Gillingham to re-rail the wagon in an hour or two. In the subsequent enquiry, the driver admitted he had not waited for the guard/secondman to walk down to the dummy (he was running about 30 mins late), and had reversed, believing the dummy would be off, which normally have been true. (It was not, because the signalman at Sittingbourne had decided to let the passenger train leave first, due to the delay on the freight). The signalman had already set the road for the passenger train out of Platform 1 and had it already proceeded, the lack of a derailer would have resulted in a very nasty incident. As the derailment only split the derailer, we could run passenger trains to our hearts content, once the end wagon was righted. But freight moves into Sheerness Steel were cancelled for two days or so, and then had to be done via Platform 2 for a week, which was shorter. Not good, but would have been a lot worse without the derailer.

[RailWest]

Correct, the points at the Templecombe end were too far from the box to be mechanically worked. I don't know the history, but either there would have had to be a second box or perhaps the loop was extended at some time?

The original loop and box at Stalbridge were north of the level-crossing. When the loop was extended and the new box opened in 1903 adjacent to the LC then the points at the north end were worked by a new GF (originally 2 levers, later extended to 3) because of their distance from the new SB. GF abolished and loop points converted to motor working in 1955.

 

Do not forgot also that 5 sets of points were converted to motor operation i/c/w the 1933 alterations at the former Templecombe No 3 Junction.

 

However...I do not see that any of the above is relevant to the circumstances in the original question about FPLs :-)

Edited January 30, 2018 by RailWest

[bécasse]

You will note the middle road at Sheerness does not have a trap point but a form of derailer (splits both ways), as there is no safe "trap" to left or right. On my very first day alone, as an Assistant SM at Sittingbourne, after several weeks trailing behind one of the other two much more experienced ASM's, I had to deal with a freight derailed on that derailer. The usual move was for the loco to propel the train in reverse from the middle road back on to the single line and then into Sheerness Steel's sidings. The move was controlled by the dummy at the Sittingbourne end, which was hard to see for the driver. The train was a set of MCV's and a Class 73. I cannot recall whether there was a guard or a second man, who was supposed to operate the ground frame and then proceed to the far end to give handsignals to the driver when the dummy was cleared. An Area Inspector soon turned up behind me to take over investigation of the cause whilst I dealt with trying to get services running again (the end vehicle was tilted at about 30 degrees towards the road from Platform 1, and we had a passenger train stuck there.) We inched the EMU out of the platform with our hearts in our mouths, and then awaited the CM&EE crew from Gillingham to re-rail the wagon in an hour or two. In the subsequent enquiry, the driver admitted he had not waited for the guard/secondman to walk down to the dummy (he was running about 30 mins late), and had reversed, believing the dummy would be off, which normally have been true. (It was not, because the signalman at Sittingbourne had decided to let the passenger train leave first, due to the delay on the freight). The signalman had already set the road for the passenger train out of Platform 1 and had it already proceeded, the lack of a derailer would have resulted in a very nasty incident. As the derailment only split the derailer, we could run passenger trains to our hearts content, once the end wagon was righted. But freight moves into Sheerness Steel were cancelled for two days or so, and then had to be done via Platform 2 for a week, which was shorter. Not good, but would have been a lot worse without the derailer.

 

And here is a photo of said "derailer" in 1963, which our S&T minder (who was actually someone very senior from Wimbledon) described as an "either side trap point". He was quite (no, very) rude about the device, which he and a number of his colleagues considered unsafe because the only certain thing about it was that it would derail a runaway train without giving any certainty as to whether the derailment would be to the right or the left, his view being that the point blades should have been operated separately with just one being opened at a time according to what other routes were set.

 

 

The 1959 and 1962 Kent schemes included a number of "clever" signalling ideas, some of which, like this one, lasted despite being potentially dangerous, while others lasted little longer than the Inspecting Officer's visit (which by 1962 took place on the day a scheme came into operation). The worst example, which apparently had the IO speechless, was the introduction of permissive working of passenger trains on the down roads at Elmstead Woods (where guards of trains at a stand were instructed to go back and lay detonators when they heard the following train hoot-up - I joke not, I have seen both the actual call-on signals and the [quickly withdrawn] instructions.

Edited January 30, 2018 by bécasse

[TheSignalEngineer]

That's the Wide to Gauge trap in the platform road. The derailer was in the middle road.

 

WTG traps are usually OK at low speed as they act as a retarder rather than a derailer. 

Edited January 30, 2018 by TheSignalEngineer

[The Stationmaster]

You are of course correct about there being two releases, one per crossover pair.

 

But you have not spotted the contradiction - both the crossovers within the platforms become facing points to passenger trains, when they leave Sheerness, at least for the final car of the unit (or drawn vehicles, of which Sheerness had a fair number on charters). So why the FPL out at the Westminster Straight and not within the platforms? (cf the preceding debate in this thread). I can only surmise that speed is the factor. Despite trawling through signalling regs and GA's from around that period, I can see no specific explanation on the principle, other than a general reference to a need for FPL's "appropriate to the safe passage of passenger trains". I guess the variation allowed must have resided within the finer detail of signalling design principles, with which I am not familiar, as a non-engineer.

 

Perhaps a signalling engineer on here may have a more informed comment?

 

From memory (dangerous, but ...) it was not covered in the Southern Railway Signalling Principles - which were actually printed in a book of which I have a copy - but might have been covered by Drawing Office Instructions.  However release points without FPLs were common fare on the GWR and elsewhere and perhaps somebody (or lots of somebodies) thought in their innocence that there wouldn't be cases of trailing bogies making facing moves through such points because the train was standing clear of them when the engine ran round.

 

The release crossovers at Sheerness-On-Sea do not appear to have been altered at the time of resignalling but the trap points on the platform lines were new additions at that time.  Presumably due to the single line but that was there long before resignalling and in the case of a terminus providing traps would not confer any operational/train running advantage (compared with adding them at a single line crossing station).  So it looks as if the resignalling ath the time of electrification adopted a 'belt & braces' approach for reasons which might now be very difficult to ascertain.

[Oldddudders]

The 1959 and 1962 Kent schemes included a number of "clever" signalling ideas, some of which, like this one, lasted despite being potentially dangerous, while others lasted little longer than the Inspecting Officer's visit (which by 1962 took place on the day a scheme came into operation). The worst example, which apparently had the IO speechless, was the introduction of permissive working of passenger trains on the down roads at Elmstead Woods (where guards of trains at a stand were instructed to go back and lay detonators when they heard the following train hoot-up - I joke not, I have seen both the actual call-on signals and the [quickly withdrawn] instructions.

 

The release crossovers at Sheerness-On-Sea do not appear to have been altered at the time of resignalling but the trap points on the platform lines were new additions at that time.  Presumably due to the single line but that was there long before resignalling and in the case of a terminus providing traps would not confer any operational/train running advantage (compared with adding them at a single line crossing station).  So it looks as if the resignalling ath the time of electrification adopted a 'belt & braces' approach for reasons which might now be very difficult to ascertain.

 

Left hand, right hand in signal design? Pushing the boundaries in busy SE London, tightening safety on leisurely Sheppey. Odd. Perhaps the Elmstead Woods idea was simply stageworks, intended to simplify works before Hither Green and Chislehurst were in full communication?

[Paul_C]

This may help. The diagram of the signalling at Sheerness in 1961, at electrification and installation of MAS, has many similarities to your layout. The actual layout differs little from the pre-electrified version. 

 

Sheerness signalling diagram 1961.docx

 

You will notice that the centre road has GF operated crossovers at the stops ends, neither with an FPL. 1 for release and 2 and 3 for each pair of points. The remainder of points within the station area were motorised and operated from Sittingbourne panel.

 

Whereas the GF operated junction at the left of the diagram, to release trains from the Westminster Straight (from the Dockyard), does include a FPL.

 

Hi Mike,

 

Any chance of reposting this in a different format please? I've tried to download but it insists that I need "Office" to do so.

 

Regards,

Paul.

[bécasse]

[Geep7]

So, i've decided that i'll use manual rodding for the points and signals, but just a question about an electronic release for the ground frame. I presume this would mean not having a rodding run to the ground frame from the signal box? (the answer is probably obvious)

Edited February 19, 2018 by Geep7

[Geep7]

Something that has occurred to me. Is it possible that the semaphore signals on this branch would be operated by Pneumatic or electric motors by 1969?

[RailWest]

So, i've decided that i'll use manual rodding for the points and signals, but just a question about an electronic release for the ground frame. I presume this would mean not having a rodding run to the ground frame from the signal box? (the answer is probably obvious)

Yes...and yes :-)