Signalling Layout Signalling

[cbrailways]

We have recently had several queries concerning how to signal a layout, but we don't seem to have a dedicated topic heading for that (there is an equivalent for Permanent Way). I for one (after 50 years in the S&T industry) am always willing to help others in that respect, and think that having a dedicated topic heading would help others looking for assistance a place to look rather than delving through numerous other topics.

 

[john lewsey]

That is a great idea
John

 

[Tony Overton]

I agree also with your idea, railway signalling is a minefield.

There are so many misconceptions. A practise seen during the BR period may not have existed during the inter war years and going back further before 1923 the GWR did things one way, the LSWR another, and the MR yet another. Then we have things that some modellers may not be aware of at all, such as MR distant signal arms being painted red and their lamps showing red when ‘on’ before grouping.

 

[Martin Shaw]

A very good idea Chris, it is a much misunderstood and therefore ignored part of railways. I can't claim 50 years in the S&T but I had some time with the LM S&T and many years in the heritage sector, count me in.
Martin

 

[Yorkshire Dave]

Likewise this is a good idea.

And an anecdote to this. My sister (who works in a London signalbox) and my then young nephew and niece visited a model railway show many years ago and the first thing she said to me when looking at a british based layout was 'the signals are all in the wrong place'.

 

[Steve Cook]

We have recently had several queries concerning how to signal a layout, but we don't seem to have a dedicated topic heading for that (there is an equivalent for Permanent Way). I for one (after 50 years in the S&T industry) am always willing to help others in that respect, and think that having a dedicated topic heading would help others looking for assistance a place to look rather than delving through numerous other topics.

Hey cb, thanks for the suggestion - let the admin team take it off-board and we'll have a discussion therein.

Undoubtedly it will be helpful, but I do wonder if the traffic will be high enough for an independent section - perhaps combining it with the Permanent Way area and allowing prefixes to differentiate between the two will be an acceptable option...?

It will certainly be useful to be able to call on your experience so lets see what we can come up with.

Cheers
Steve

 

[cbrailways]

Thanks Steve.

 

[John Duffy]

This is a good idea. One of the challenges facing a modeller with a layout that is not a prototype is establishing the appropriate signalling. As pointed out earlier there are of course variations between companies and eras. There is lots of research materials available but these mostly cover the equipment and what was where, rather than why that piece of equipment was where is was and what job it allowed to happen.

That tricky aspect for fictitious locations is being able to apply basic rules to establish a realistic signalling arrangement.

Having some expertise in one place will be a great help.

John

 

[Pencarrow]

This is a good idea. One of the challenges facing a modeller with a layout that is not a prototype is establishing the appropriate signalling. As pointed out earlier there are of course variations between companies and eras. There is lots of research materials available but these mostly cover the equipment and what was where, rather than why that piece of equipment was where is was and what job it allowed to happen.

That tricky aspect for fictitious locations is being able to apply basic rules to establish a realistic signalling arrangement.

Having some expertise in one place will be a great help.

John

Definitely a discussion area I'm interested in seeking help and advice in.

As has been said it's not so much a problem when modelling a prototype location that's well covered with photos etc. But, if you've just knocked up a small cameo layout in 4mm, that has taken a few liberties with regard to prototype practice in order to fit something interesting into 5', then it becomes a problem.

As a result I'm sure there will also be a few liberties on the signalling front, but I'd like something that doesn't scream WRONG at everyone. There are only 2 signals that are 'on board' but my current conundrum relates to routing the point rodding runs.

The layout in question is Polsarrett, 4mm/00, set in early 1960s Cornwall somewhere along the ex LSWR Wadebridge-Bodmin North line.

So in summary I'm really glad to hear we have expertise in the forum - just now pondering where to post the question...

 

[Pencarrow]

Further to the above I've posted a new thread here: 4mm - Polsarrett S&T

Advice welcomed.

 

[J_F_S]

I strongly support the idea of a separate S&T thread - most people struggle with signalling (as a glance round most exhibitions will soon show!) and I think much of that is down not having an easy way of asking for help. I would certainly be willling to add anything I can by way of help.

Here are a couple of my own projects. Firstly the Home Signals on my own (fictitious of course) Minories layout, based on Southern Railway practice in BR days. These signals had to be designed to deal with very difficult sighting issues being immediately outside the tunnel mouth. The single Calling-on arm is an example of how the Southern used off-the-shelf Westinghouse bits to make a non-standard signal. I had lengthy debates with my S&T friends about how the Southern might have solved this problem - this was the concensus:-

And the - slightly more standard - starters:-


Secondly, here is a fully locked (mechanically and electrically) 70 lever frame for John Elliott's (real location) Leeds City Wellington layout which is (as far as we can judge) a very close copy of how it was done on the real thing. In this case, we had the original box diagram to work to, but had to "reverse-engineer" how it was intended to work the layout and how to interlock the frame accordingly. As we are interesting in Signalling, we wanted it done "right" and we work the layout as "right" as we can. The frame and locking is built from kits available to members of the Scalefour Society.


It uses the same principle as the Great Western 5-bar VT locking - not least because it is very compact - though it actually only has 4 bars for practicality. Of course, I should have copied the Midland design of frame, but making catch handles strong enough to withstand the locking proved impossible!

This project has appeared in MRJ recently (one more installment still to come), where I described how we tackled some of the tricky bits.

Experts will spot that a lot of creativity was needed to fit all the locking into a very tight space.

Looking forward to a new dedicated topic and the contributions thereto!

Best Wishes,
Howard

 

[Tony Overton]

My reaction to seeing the photo of the lever frame is wow........... and cor blimey.........

 

[cbrailways]

Howard. What a fantastic job. Can you post some more details in the PW topic for now? Are those electric locks I see behind the levers?

 

[Stephen Freeman]

Yes we have previously marvelled at Howards signals on S4um, I myself am in the course of constructing some of said lever frames though we have decided to give the mechanical interlocking a miss, life is too short, and just have the levers operating microswitches which operate points and signals. In fact it is almost done. I will see if I can do some photos if interested

 

[Pannier Tank]

Howard. What a fantastic job. Can you post some more details in the PW topic for now? Are those electric locks I see behind the levers?

I was also wondering what the "Push to release" buttons, 'Back' and 'Back Over' LEDs were for.

 

[john lewsey]

Those signals look amazing, really very good
John

 

[simond]

Quite outstanding. Very impressive!

 

[J_F_S]

Many thanks for the kind comments chaps, I will just hold fire on posting too much more for now in the hope we might push our Admins for some signalling action!!
But just to answer the immediate questions:- Yes, the gubbins behind the levers are indeed the electric locks - the tricky design challenge was to enable them to be fitted in the 10mm pitch of the levers.
In terms of the buttons, these are "Economiser" buttons which take several different guises on the real thing. They avoid locks being "picked-up" for long periods. So no current flows to the lock until the signalman pushes the release button. If the lock circuit is "Clear", the lock picks-up and holds itself "in". The green LED illuminates and the signaller knows the lever is free to pull (providing it is not mechanically locked!). When the lever moves through its stroke, the lock drops out. The terms "BACK" and "OVER" (pinched from Sykes' Lock and Block system) indicates if the lever is locked "in" or "out" - depending on the function of the lever. Because the Midland Railway Rotary Block system is implemented, some of the Signal levers are lock whilst reversed. but of course, the signalman must be free to replace the signal in case of emergency - such levers are backlocked part-way through their replacement stroke - enough to replace the signal, not enough to free the locking. Such a lock is known as a "b" position lock. Those who can beg or borrow a copy of MRJ no 285, which was published in September, will find much more detail.

Just to show that we are not completely stuck in the ancient past, here is the latest project which is the control logic for an NX panel for the Leeds West hidden sidings. Three diode arrays provide the route select, locking and indication logic and the small boards sticking up are the plug-in relay controllers for the individual points and signals. It is only half finished and is the prototype for two further panels in the other hidden sidings. Anyone interested to learn more about John's layout must go to the Dark Side:- Leeds City, the Midland Side, in 4mm.
These PCBs were custom made in China to GERBER designs we produced ourselves - the big one (which contains nearly 6000 holes!) cost £6.10 including tax and delivery! It took 23 hours from placing of the order to get made and five days to be delivered.


Best Wishes,
Howard

 

[cbrailways]

Thanks for the info Howard.

 

[J_F_S]

I myself am in the course of constructing some of said lever frames though we have decided to give the mechanical interlocking a miss, life is too short ...

Hello Stephen,

Just be sure to install the drive pins in the levers - that way you can easily retrofit the locking when the pace of life eases a bit! And / if you find life difficult with an unlocked frame!

Looking forward to seeing the finished job.

Best Wishes,
Howard