Single-Lever Crossover suitability? (Victorian/Edwardian period)

[St Enodoc]

It was there in 1933:

 

https://signalbox.org/~SBdiagram.php/?id= 208

 

but had certainly gone by 1966:

 

https://www.derekhayward.co.uk/BluebellRailway-1/Explore/Sheffield-Park-Station/i-rfHcVxG/A

 

[Grovenor]

You are still missing the shunt signals to get back into the station from the Up main, adjacent to the first point end.

[Michael Hodgson]

1 hour ago, Grovenor said:

You are still missing the shunt signals to get back into the station from the Up main, adjacent to the first point end.

Probably on a gantry, not unlike in your first posting.

[Lacathedrale]

Thank you @bécasse I want to show the Advanced Starter and Shunt-Ahead signal on the layout - there is a road overbridge scenic break so that seems reasonable for me to justify it! Added as No. 18 and everything shuffled up one.

 

 

@Grovenor not sure how I missed the Up Main shunt signal, but added.

 

 

I added as a new lever  instead of the spare lever 9, because with the normal lies to shunt P1, P2, P3 only involves levers, 28, 29, 30 and 31.  The siding and dock from the up main both require levers on opposite ends of the cabin (30, 31 and 3, 4) so on balance a higher numbered lever would be better - but I reckon it needs to slot in below the up main point levers?

 

@Michael Hodgson - I haven't built a single working signal yet, so I don't quite want to say I'm going to build a gantry with 9 on it - we'll have to see!

[TheSignalEngineer]

Sorry to be joining the game a bit late, but I was struck down by man-flu so not been feeling to brilliant.

I had seen the thread and most of my first thoughts regarding lie of points and which ones to double end have already been covered.

There are possibly probably four ends where FPLs  aren't strictly necessary, two in sidings and two trailing points in the Up Main which don't have a facing passenger move. Another change to FPLs that I have used in real life is to use one lever where there are two points back to back working 'Flip-Flop' with one in and the other out. I don't know if the LB&SC ever did that but I will look at a few plans later

Regarding numbering, although railways did use different systems even amongst their own boxes the usuasl system was points and sahunt signals in the middle, Down signals at one end and Up signals at the other. To get the proper direction which way round is the frame, trackside or back wall of the box? Trackside with the signalman working facing the track was the most common. That determines the numbering sequence and also how the box diagram would be orientated. From the layout thread I think the box was on the Pilot Siding side of the track.

Numbers would be arranged to cut down walking up and down the frame for a route, and to avoid the dreaded 'Pull-Between' where you have to pull 5 points then 3 points followed by 4 FPL.

Proper arrangement of the numbers can cut down the length of locking bars and also reduce the number of locking trays needed in the frame.

I will take another look at it later if you can answer the questions about orientation of the frame.

[TheSignalEngineer]

8 hours ago, TheSignalEngineer said:

Another change to FPLs that I have used in real life is to use one lever where there are two points back to back working 'Flip-Flop' with one in and the other out. I don't know if the LB&SC ever did that but I will look at a few plans later

I found a sketch of Epsom Downs quoted as being 1920 with back to back FPLs worked by one lever. 

[Lacathedrale]

My idea is for the signal box to sit between p1 and the pilot siding facing the track.

 

@TheSignalEngineer any advice you can give about modifications I would appreciate, my brain is jelly thinking about it!

[TheSignalEngineer]

10 hours ago, Lacathedrale said:

my brain is jelly thinking about it!

I can well understand that given the quirks in Saxby's signalling installations. Some are difficult for me to understand and I spent my whole career in the industry

 

 

[Lacathedrale]

@TheSignalEngineer are you able to explain the flip-flop back-to-back FPL?

[Michael Hodgson]

An FPL lever may lock the point when the lever is reverse - to set route simply pull point lever then the FPL

or it can lock when normal - to change point, pull FPL to unlock it, pull lever, put FPL back to relock

FPL levers are said to "stand normal" or "stand reverse" depending on which option S&T took at a particular box.

 

But you only need to lock facing points, so with two points toe to toe, you require one point locked for a train going one way, or the other to come back again.  But as you can't be going both ways at the same time, it's possible to use the same lever to lock both.  So you lock one with the lever normal, the other with it reverse.

 

[Nick C]

On 17/02/2024 at 20:14, Lacathedrale said:

 

A few thoughts...

• Points 7 would probably be a hand-point in real life as they're in the sidings.
• You then only need one of 22/23, which would apply to either road depending on the lie of 7.
• The pilot siding crossover doesn't need FPLs as there's no facing passenger moves in either direction.
• Crossovers commonly would have had separate FPLs for either end. You don't need to lock trailing moves (and it was often disallowed by the locking), so crossovers 1 & 5 would have separate FPLS on either end. The others all only need them on one end. 
• The exit signal from the loco siding would be at the toe of the trap point - you've drawn it much further to the right.
• The Brighton appear to have been prolific providers of shunt signals, as I discussed on Linny's thread the other day, 22 at Littlehampton prior to the SR's resignalling. While the SR would have had just one (32) for all movements back in from the up main, I think the LBSC would have had more - it seems like they had a pair at each facing point!
• As others have mentioned, a bit of renumbering is needed. 
• I'm not sure what signal 18 is for? You wouldn't have a shunt-ahead on an advanced starter, it defeats the point. 17 should be a train length clear of 32 so that a train can draw up to it to shunt across without the section in advance needing to be clear.
• I'd also expect an outer home for such a busy station, but that'll be off-stage, 440 yards prior to inner home to allow for a clearing point.

[Lacathedrale]

Thank you @Nick C - I've removed 7 and 23. Frankly I'm not sure I'm going to include FPLs on my lever frame at all, but duly noted for the extras required if I do.

 

Signal 18 is because the Advanced Starter isn't a full train length from 32, because otherwise it would be off-layout. If I ever add a nice curved corner section to the layout I'll be sure to remove 18, move 17 and add the Outer Home :)

 

Good point about potential additional shunts!

[TheSignalEngineer]

3 hours ago, Lacathedrale said:

@TheSignalEngineer are you able to explain the flip-flop back-to-back FPL?

One stands normally in, the other normally out. It helps to simplify the interlocking in some instances as pulling the signal lever requires the FPL lever in the correct position thus eliminating signal to signal locking on conflicting head-on routes over the same piece of track

[bécasse]

2 hours ago, TheSignalEngineer said:

One stands normally in, the other normally out. It helps to simplify the interlocking in some instances as pulling the signal lever requires the FPL lever in the correct position thus eliminating signal to signal locking on conflicting head-on routes over the same piece of track

Known to some signal engineers as "direction levers" and, depending on the track layout, their use can significantly simplify the interlocking. Levers which work more than one fpl, whilst commonplace (usually where one facing point was followed almost immediately by another), could be hard to work but that didn't usually apply to these direction levers as (typically) there was only a single lifting locking bar (between the two facing points) and while one lock was being put in the other was being released.

[TheSignalEngineer]

I've not forgotten about you, just doing a bit of revision on Saxby and LB&SC matters.

Regarding the double slip in the siding I found two sketches on John Hinson's signalbox.org website albeit trailing onto the running line.

 

They were at Horsham Junction c1900 and Leatherhead in 1927.

 

Re-orientated and converted to your numbering they would look like this:-

 

[Nick C]

10 hours ago, TheSignalEngineer said:

I've not forgotten about you, just doing a bit of revision on Saxby and LB&SC matters.

Regarding the double slip in the siding I found two sketches on John Hinson's signalbox.org website albeit trailing onto the running line.

 

They were at Horsham Junction c1900 and Leatherhead in 1927.

 

Re-orientated and converted to your numbering they would look like this:-

 

That only works if the two pairs of switches at each end of the slip are separately controlled though - I believe that William is using RTR pointwork so they'll be on a single tiebar?

Edited February 20 by Nick C

[TheSignalEngineer]

1 hour ago, Nick C said:

That only works if the two pairs of switches at each end of the slip are separately controlled though - I believe that William is using RTR pointwork so they'll be on a single tiebar?

One of the compromises in modelling. Unless you build it yourself it's impossible to replicate reality, and with the materials available get it to work reliably.

In later years it would be probable that 7B would become 3C leaving 7A as a single end.

[RailWest]

Would not 7A just become a hand-point as well?

[TheSignalEngineer]

29 minutes ago, RailWest said:

Would not 7A just become a hand-point as well?

Three LB&SC examples I've found from the early C20 have a worked point end on the side of a double slip coming in from the main line.

I've found nine examples across four railways that would tie in with what I drew but there are others using hand points for the incoming points.

Finding one with a facing entry like the OP is quite rare even at terminal stations. The only one I can think of so far on double track was the entrance to the run round and carriage sidings at Ilfracombe, where all switches on the double slip were box worked.

In my opinion this would be the preferable method for a facing entry as it ensures that the incoming train doesn't need to stop and observe the lie of the points when making a move from the Down Home to the Run Round or Siding.