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Signalling an ex-L&SWR BLT

Unread postPosted: Sat Nov 2, 2013 4:50 pm
by Chris Osment
Somewhat rashly perhaps <g>, recently I agreed to help someone plan the signalling signalling for his 4mm ex-L&SWR-based layout. As sadly is all too common with such things, the trackwork has been laid already and only now is he trying to superimpose some signalling on it.

The location is an imaginery single-line branch terminus somewhere between Salisbury and Exeter, built by the L&SWR circa late-1860s. As such the eventual signal-box might well have been a L&SWR Type 1, tho' the builder has some interest in using a Type 4 instead. The model is based in the BR period.

The basic layout is fairly straightforward, but there are one or two querks which could be signalled in a number of different ways, so I'd be interested in views from forum members please. There is a rough sketch HERE of my initial ideas. Please note the following:-

1. I have not included any spares at this stage, just trying to get the basic numbering sequence right for the bare essentials.
2. For ease of the owner's modelling purposes I have ignored the possibility that there might well have been some push-pull levers.
3. The signal-box location might be at any of the places marked 'A', 'B' or 'C' on the plan - at the moment the builder has it at 'B', so I have worked around that.
4. To avoid 'clutter' I decided not to have an inner home adjacent to shunt 13, but instead made 13 a 'running shunt' (as per Padstow). I have included shunt 14 as a 'draw ahead' to allow down trains to be admitted direct to the loop (cribbed a bit from Seaton).
5. I have assumed that shunt 6 reads direct ahead towards 2, as well as across 8 into the dock siding, so that engines can shunt up towards 2 without the gates being bolted across the road (borrowed the idea from Wadebridge West).

It is the level-crossing which causes me the most uncertainty. The distance from shunt 13 to the gates is about an engine + one bogie coach on the model. If the SB was at 'A', then I would have a GF at the LC released from the SB and with slots on 2 and 14/15. If the box was at 'C' then I reckon that points 11 and 8 could be worked from the SB (akin to Wadebridge West again), but have a GF at points 4 released from the SB (as at Bodmin North). With the box at 'B' - hmmm - having a GF at the crossing as well seems a bit of overkill, so I am thinking of crossing-keeper to work the actual gates but bolt them directly from the SB (as at Glastonbury and Eggesford). What do you reckon???

Another complication is that a short distance up the line, but not included in my sketch, is another LC which is assumed to have been a WWII addition for a new road to serve a wartime camp. In this case then I am assuming essentially a stand-alone GF with its own signals, but might it perhaps slot 2 as its Up Home instead and in turn have its own Down Home slotted by the SB as an Outer Home? Maybe in that case use that Down (Outer) Home to protect the LC nearer to the station and move 15 to locate with 13 (omitting 14 then) ?

Re: Signalling an ex-L&SWR BLT

Unread postPosted: Sat Nov 2, 2013 9:28 pm
by davidwoodcock
I think that is what I would have come up with, although I think that in reality the two dummies for the engine-release crossover would have been on one push-pull lever (but understand why one might wish to avoid that on a model). Depending on the precise position of that crossover relative to the platform (doubtless somewhat short in model form) I would have been tempted to add an FPL since I suspect that the stock for departures would sometimes be propelled back down to the stops. If the crossover is too far from the box to be worked (or if it is "unsighted") then the possibilities seem to be a GF with or without signals (as Seaton) either released from the box or with just a bolt on the platform road points. A branch built in the 1860s would almost certainly have had its own loco shed.

I feel certain that had the construction of a type 4 box become necessary it would have been sited such as to be able to work the original level crossing even if the original box hadn't been. With the original box in position B, I feel that the most likely arrangement is that the signalman would have worked the gates by hand with, as you show, a gate lock lever on the frame. It is, after all, a simple single line terminus and a crossing keeper would have been overkill (and unaffordable by the late 1920s).

The wartime LC would have been put in with a minimum of alterations so the slot on number 2 certainly feels right. However that leads me to wonder if, even before the WWII crossing was put in, there would have been a shunt ahead signal under number 2 - it depends on how busy the station is intended to be and, particularly, how often it would play host to two trains, certainly the ability to shunt a goods while a passenger train was en route to the "junction" could have been useful. In reality, if there were a shunt ahead arm, this would probably have been another push-pull lever.

In the down direction, moving the home 15 out beyond the new crossing (with a slot), abolishing 14 and using the lever to work a new inner home alongside 13 also seems right and shouldn't have required too much alteration to the locking.

Re: Signalling an ex-L&SWR BLT

Unread postPosted: Sun Nov 3, 2013 12:23 am
by Pete2320
I think location "B" is the least likely position for the signalbox. if the "Type 4" then I think it would go by the crossing with a ground frame at "4".
Concerning both crossings, I think if they were controlled by GF then they would either be released from the signalbox or have slots/their own signals, not both.
I think the wartime crossing could legitamatley not have any signals at all if that suits, but otherwise as David Woodcock suggests, move 15 back to protect the crossing and provide 14 as an inner home.


Re: Signalling an ex-L&SWR BLT

Unread postPosted: Mon Nov 4, 2013 7:11 pm
by Chris Osment
My thanks for the comments so far, which I am 'digesting' slowly...

In the meantime....I am advised that the distance between the two LCs on the model is approx an engine + 5 coaches.