Signal's & point rodding

[Sr-Dixon]

Hi all,

 

Im reaching the point now where i need to start thinking of signal types and locations, and as i want to include point rodding aswell yet have no idea what to be doing i thought id mix both together!

 

the layout is a lswr built branchline terminus, and ive detailed on the plan provided the basic locations of buildings etc,

 

so! can anyone help?

 

Thanks,

Paul

[TheSignalEngineer]

Looking at the part numbers shown on you plan it appears you have a diamond in the middle. The run round and access to the sidings would need a double slip. Also the parts mix Code 75 and Code 100 plus concrete bearer points which are very modern-image.

 

The proximity of the level crossing adds problems and there is a temptation to over-signal layouts in those circumstances.

 

Could you give some details of the traffic pattern and how it is shunted as the siding layout seems quite restrictive operaationally.

[bécasse]

Although the signal box is in the ideal position if there wasn't a level crossing, given the presence of the latter, the box would almost certainly have been situated next to it for economy of working. (Someone has to work the crossing, the signalman is hardly overworked and you wouldn't want to pay two sets of wages.)

 

I assume that you have a double slip opposite where you show the signal box. In which case, the left hand half of the double slip would be worked as a crossover with the goods yard access point, and the latter would have a facing point lock with locking bar.

 

The LSWR, and subsequently the SR, used a variety of arrangements to control engine release crossovers but I think that the simplest is that used at Seaton following the SR rebuilding there in the 1930s - both crossover points are worked (as a pair) by the signal box as is a facing point lock on the point adjacent to the platform face, it doesn't however have a locking bar and there are no signals (the fpl would be interlocked with the platform starting signal, signal off=fpl bolt in).

 

The signals for trains approaching the terminal would be a fixed distant off-stage, a home before the level crossing and a "running" shunt before the point into the loop/yard. This would require all arriving trains, including freights, to come into the platform first, but if direct entry to the loop/yard is required there would be an additional shunt signal adjacent to the home. The running shunt would be "off" for all movements into the terminal as it proves that the points are set correctly.

 

Signals in the other direction would be a platform starter, an (advance) starter just before the crossing gates and a single yellow miniature arm shunt signal adjacent to the twin toe of the double slip; the yellow shunt when "off" would permit movement from either the loop or the yard to the running line.

 

Ignoring the requirements of various locks for the level crossing, four rodding runs would be required - one to the two ends of the engine release crossover, one to its facing point lock, one to both ends of the loop/yard access and one to its facing point lock. All the rodding runs would require compensators; there is an excellent article in the current issue of Wild Swan's Great Western Railway Journal explaining how compensators are set out, and although it obviously reflects GWR practice this is one case where the laws of physics meant that all railway companies were pretty much alike.

[Sr-Dixon]

Hi,

 

Thanks for your responses,

Firstly that is a double slip, due to lack of space rather than seperate points (I want to keep all points on one board). And the types of track work were accidental, they're all wooden sleeper code 75.

 

The basic running is quite a low frequency of passenger running, freeing the platform for goods entry, wagons being shunted to the varying parts from here, and reversed for rebuilding a train of empties etc, brake vans being stored in the spare space by the run around.

 

I'm starting to think that I might do better being rid of the level crossing and add a road bridge, may also help hide the tightness of the curve, I can already imagine the scenic possibilities of this so we'll say be rid of the level crossing! (Which is annoying as I've just come back from alton after buying it!).

 

Cheers

Paul

[bécasse]

With no level crossing, the signal box is fine where you have it. Like most model railways, the layout is inevitably tight but it certainly could be LSWR in origin. The small loco shed is an important feature, not only did almost every LSWR branch have one but most remained in use until the end of steam. (Whereas a lot of railway companies eliminated many of their branch termini loco sheds once the 48 hour working week came in after WWI because it became difficult to roster loco crews efficiently.)

[Sr-Dixon]

Excellent I prefer the scenic view (in my mind) of not having the level crossing anyway, plus now I get to scratchbuild a bridge!

 

Also now need to locate a plan for a lswr engine shed, the one I have at the moment is a gwr one but that was from the previous attempt.

 

Will still however be a fun project, and fun running too as I'm sure small size of the yard will produce some challenges

[RailWest]

"The LSWR, and subsequently the SR, used a variety of arrangements to control engine release crossovers but I think that the simplest is that used at Seaton following the SR rebuilding there in the 1930s - both crossover points are worked (as a pair) by the signal box as is a facing point lock on the point adjacent to the platform face, it doesn't however have a locking bar and there are no signals (the fpl would be interlocked with the platform starting signal, signal off=fpl bolt in)."

 

It may be the simplest perhaps, but how common was it? - Seaton was the only example which comes to mind. Surely far more common for the L&SWR was the use of ground signals at each end of the crossover and no FPL? If the signal-box is at the end of the platform, then work it from there, but if further away at the level-crossing then I would provide a local ground-frame (as at Bodmin (North)).

[bécasse]

I would suggest that the most typical L&SWR arrangement was with a single shunt signal at the point alongside the platform and, as Chris has said, no fpl, this was certainly the arrangement at Sidmouth and Lyme Regis. At stations with shunt signals at both ends of the crossover there was usually some good reason for it, and they tended to have more complex layouts anyway, examples being Swanage and Bude. The point detector on the shunt signal effectively replaces the fpl and therefore the shunt has to be off with the crossover points normal before the platform starter can be cleared; the shunt can be pulled off with the crossover points either normal or reversed (whereas the fpl would only bolt the point alongside the platform normal).

 

I suggested the fpl and no shunt signal arrangement as at Seaton because it was installed like that by the Southern Railway and it could therefore on the model always legitimately represent a SR alteration. If the box was short of levers (and L&SWR boxes often were) then both fpls could have been worked by the same lever, although this wouldn't have been popular with the signal man as paired fpls tended to be difficult pulls. If they were on separate levers the interlocking would almost certainly have been identical for both as they would both need to be "bolt in" for any move along the platform line.

[Sr-Dixon]

I'm still confused, feel so dumb and over my head! Sure I'll get it eventually, just need to learn the basic principles of signalling (which I know not!)

[RailWest]

Sorry to be appear contradictory again <g>, but.....

 

"I would suggest that the most typical L&SWR arrangement was with a single shunt signal at the point alongside the platform ......this was certainly the arrangement at Sidmouth and Lyme Regis.....the shunt has to be off with the crossover points normal before the platform starter can be cleared"

 

At Lyme Regis the locking table is clear that the shunt worked only for the diverging route. At Sidmouth it did indeed work for both routes, BUT it was not involved in the pull sequence for the Up Starting (No 8 ). Indeed, in contrast, 8 had to be pulled to release shunt 14 for moves straight ahead!

 

[EDIT. Also, at Swanage it was the case that the shunt (19 PULL) read only for the divergence over points 16. ]

 

"....whereas the fpl would only bolt the point alongside the platform normal......

 

Except that at Seaton the locking table shows that it bolted both ways :-)

[Sr-Dixon]

Partially in relation to signals... Would the southern have used whistle signs, and limit of shunts signs? would they be used on the scale of my layout? And what would they look like??

[phil-b259]

Partially in relation to signals... Would the southern have used whistle signs, and limit of shunts signs? would they be used on the scale of my layout? And what would they look like??

 

Whistle boards are nothing to do with signalling. They are placed on the approach to things like foot crossings to provide warning of an approaching train where sighting from the crossing is difficult. In steam days they were simply the word "Whistle" spelt out on a board - nowadays the leter "W" is used.

 

Now that is not to say the crews wouldn't use the whistle when shunting etc., - there are in fact lists of whistle codes, each one used to mean a different thing - one example would be two blasts to indicate the loco was standing clear of pointwork and it was safe for the signalman / shunter to alter them - but Whistle boards wouldn't be provided in such cases.

 

Now limit of shunt boards are a thing to be careful of because many modellers (and even some full sized railways get them wrong - I'm thinking of Churston on the PDSR here). A limit of shunt board is exactly the same in railway operating terms as a fixed red signal or a virtual buffer stop NOTHING is allowed past it, including passenger trains. If you fit a limit of shunt to your single line then either nothing will ever be allowed to depart or conversely nothing can ever arrive. Thus Limit of shunt boards tend to be restricted to double track lines, and indicate how far in the "wrong direction" a train is allowed to proceed. For example lets say a train requires to make a shunt move in the DOWN direction along the UP line. Because the UP line only has signals facing UP trains, in theory the DOWN train could carry moving in the DOWN direction all the way along the UP line and crash into the next UP train because said DOWN train has not reached anything forcing it to stop (if the DOWN train sees any signals it will only see the 'back' i.e. white and black side of them which do not apply to anything). If however a limit of shunt board is placed on the UP line with the writing facing DOWN trains then the train performing the shunt manoeuvre is forced to come to a halt and cannot proceed any further. UP trains on the other hand never see the writing on the board because they only get to see the back of it.

 

In steam days Limit of Shunt boards were, like Whistle boards simply consisted of the text on its own, however given Limit of Shunt boards are the equivalent of a fixed red signal, over time it was decided that if it simply consisted of a sign, then having it illuminated might be a good idea. Later on in the colour light era, 'fixed red' shunt signals became an option, though illuminated boards are still used in many places.

[phil-b259]

As regards signalling though, to be absolutely honest you don't need much (and neither would the prototype either). The attachment shows the general idea but basically the engine release crossover would probably be unsignalled and be a simple ground frame - possibly unlocked by the main signal box when required (It would need to be locked with the points set for straight running if the main signal arm at the station entrance was cleared for an incoming train, if the shunt signal was cleared it could be set either way).

 

The points in the yard would be hand worked except for the double slip because that gives access to the main running line. The two shunt signals on either side therefore can both be cleared if shunting is taking place wholly within the sidings but if the route has to be set out onto main line then then the left hand shunt only must be cleared. Equally if a route is set into the sidings from the main running line, then both shunts must be at danger.

 

Finally the signal on the approch to the station, if the route is set into the empty platform and the run round ground frame locked normal, the main signal comes off. If the route is set into the sidings or the ground frame is unlocked or there is a train in the platform the shunt is used.

 

[Sr-Dixon]

That settles that! Thank you kindly