help from the professionals please

When you say 'extreme hard right', do you mean that 90^o route indicator is lit? If so, you'd be heading for platform 3 so I'm not sure I completely understand the question.

All three starters would be platform mounted.

You would either have a limit of shunt board, or more likely a controlled advanced starter to define the end of the main line shunt move.

I don't think you'd need traps on the sidings, but you probably will on platform 3.

The only other things I can think of at the moment are that A1^B would probably be a controlled signal, positioned a full speed overlap away from the points (and it would be this signal that protects the points).

Also, your signal numbering will start with all the moves in one direction at one end of the frame, e.g. EB home 1, shunt 2, shunt from siding 3, and the starters and all WB moves would be at the other end of the frame. Point numbers go in the middle.

Hope this helps!

The home signal BC1, where will the shunt go? The platforms currently have colour light signals to all 3 platforms.

The guard would have had platform repeaters normally, ceiling hung so the sighting of the starter wouldn't have been an issue

Just a thought, wouldn't A1's be an X signal or would we assume the X could be further back in this case?

Interestingly I would've sworn I replied to this thread but it was in the wee small hours so perhaps I forgot to post!
My comment was that automatic signals are numbered odd in one driection of travel and even in the other so what you have labelled as A3 would be A4 and if A3 existed it would precede A1 on the eastbound. The other point that I made was that there are often gaps in the auto signal numbering to allow for resignalling so A2 would not necessarily be followed by A4, the next signal could just as easily be A6.

As far as having two routes into the same platform I believe I am correct in saying that the driver in this instance would get the same signal regardless of which of the two crossovers was selected. The selection would depend upon the condition of tracks in the area i.e. whether occupied or not but generally the signalling circuitry would have a preferred route. I think I am right in saying that such a situation exists at Arnos Grove for westbound moves from the middle platform but I can't recall the details now having not worked at that IMR for a few years. ISTR that Cockfosters has a similar double crossover into the middle platform from the eastbound much like your drawing

Brian

leaving wimbledon platform 2 is a good example.

Ooo. An interesting series of questions that has sparked my interest. Bear in mind this isn't a professional view, just a semi-educated guess. ;D

Distilling various reams of signalling school notes there is a consistency of numbering autos: EB/NB odd, WB/SB even. Signals would also be grouped together in consistent blocks, so like functions would be on adjacent levers - eg the two main starters at a terminal station would controlled signal n and on the other road n+1, then there'd be a gap and the discs below would be n+gap and n+gap plus 1 - look at Epping LW4/5 and LW31/32 for an example. Now here it can get slightly complicated....

As I understand it for New Works stuff a main stick would be number ^Aand a disc beneath it would be same number ^B unless the disc has a route indicator and then the locking cats and dogs would be quite different - again the Epping examples cover this.

I do like the headshunt joining in the middle of the scissors, very reminicaent of the arrangement at Leytonstone with the powered traps on on side to protect the tube from marauding full-size goods trains. In fact these very points are used as a text book example in the note I'm mulling over.

As you're setting this in the 70's based upon the 'New Works' ethos I'd respecfully suggest a couple of stylistic points with the arrangement of the interlocking - the signalbox would be situated next to the EB between your BC1/BC4 - this would probably mean that your BC5 would be the first signal to be controlled from a lever frame - No 1 is always at the left-hand end[1].

<wanders off to look at Central Line Eastern perils>

Right then, your A1^A would possibly be BCX695^A with A1^B being A695^B. Why 695 - well, it continues the sequence of Autos from Theydon Bois - although they were coded LV for there, they were numbered in the Auto sequence. A3 would be A692. Must add the rider that there would probably be a bigger gap, but these would be the lowest feasible numbers. A2 would (as Tom says) be a controlled starting stick - more than likely the highest number in the frame. I guess that it would be situated at or just in advance of the seven car stopping mark - however this remark could apply to your A3 with your A2 becoming A692. I'm not sure if this actually follows the locking style of the New Works; I suspect not. Intermediate Autos between controlled signals would (I guess) be a product of the 'round the bend' signals put in after Stratford and as such wouldn't be particularly appropriate.

You're quite correct in thinking that your BC5 would be ^{A B C}, however the ^A signal would be nearest the main (LP59^A-J at Newbury Park is a suitable example).

Now bearing in mind that levers in a frame would be grouped together for the signalmans convenience the headshunt area would be your BC5 ^C becoming BC1 ^A 5/6 points becoming 2, 4/5 points becoming 3, points in front of your BC6 becoming (probably at this stage) 4^B (4^C if you fit the trap and your BC6 becoming BC5 controlled from a lever frame.

Now comes the complicated bit - there's a lot of variables to be considered and a lot of possible variation. Essentially signals would be grouped together in blocks - so your BC3 would probably become BC6 on the frame - though more than likely 6 would be a spare in the frame as the 'lever block' it belongs to is more to do with the discs under the platform starting sticks than the sidings group. Let's call it a spare and go onto considering the rest of the layout - the discs under the platform starters would they have route indicators - I suspect they might in real life - looking at the Epping examples. Right, the next thing you've gotta consider is what the signalman is going to operate most often - you're going to want those levers all grouped together I'd suggest that your BC 2,3,4 main sticks would become 7,8,9 on the hypothetical frame, <looks at Hainault and Debden for inspiration> - your 2/3 bay points would become 10 points on the frame with the disc under 7 (your BC2) becoming 11. Disc under 8 (your BC3) becoming 12, with the crossover between 1/2 immediately in front becoming 13, the crossover in the same direction in the scissors would become 14. Disc under 9 (your BC4) becoming 15 and the facing crossover this reads over would become 16.

I'd be tempted to put in either a spare or a king for automatic working on lever 17. Your BC1 main stick will then become 18 on the frame with the disc below becoming 19.

Your A1^B - A695^B would have a repeater underneath RBC17/18 and under your A1^A - BCX695^B there'd be repeater RA695^B and fog
repeater FRBC17/18.

Of course I've forgotten that this was planned to be a through station, so you'd probably need to add 6 or seven spares so BC18/19 would become something like BC25/26.

Hope this helps. I think I've followed the spirit of the Eastern Extensions locking, though my design is coloured by non-LT interlocking which is part of my real-life job.

(Puts tin hat on and waits for other signalling types to pull the suggestions to shreds )

[1] as ever there is an exception to this rule - when EUston was rebuilt from 2 back-to-back (?188) lever frames into two front-to-front the numbering was reversed.