Signalling help on my simple 8x4

[The Stationmaster]

   Interesting - However I can show you a 1980s two aspect based scheme where AWS was not provided on red / green signals.

 

Another case of regional variation possibly?

 

More likely designers, and the ops sign-off, using their heads about the situation of the signal I suspect.

 

Oddly in later years it developed a nasty reputation for SPADs due to the lack of any lineside points of reference when approaching it after dark.

[The Stationmaster]

In reality if only two ground signals were provided in the sidings and both could be cleared at the same time for shunting, you would find that the train would stop and start wherever the shunter dictated by handsignals to the driver. If in a location out of sight of the signalman there would often be a local instruction as to what could be done with both signals off and that the signalman had to ensure that no shunt move was about to take place before putting the signals back to danger and setting a conflicting route across the exit points. 

As far as route indications are concerned at ground signals, around 1980 these were usually minimal, and were limited to differentiating between routes of a considerable difference in nature or length such as

1. Out to the main line or into the headshunt - indication NCK for the headshunt.
2. Electrified and non-electrified lines - e.g. in the days of the 1500v electrics over Woodhead, Piccadilly station had indications to differentiate between routes available to AC or DC electric trains.
3. Routes running wrong line eg to a limit of shunt - 'X' would be included such as XDM 

From the Headshunt to different sidings there would be no need for route indications if all moves were under control of the shunter. The shunter should instruct the driver as to the moves to take place before starting.

 

And of course on the WR GPLs very rarely had any indication of route - only started to appear in the 1980s (with one earlier exception) and then only if the signal included a route from a yard or siding onto a running line among its list of routes.

Ultimately that's what signal designers do on the prototype. Yes they have lots of fancy tools to help them, but it all basically comes down to 'these are the moves we wish to do, now what signals are necessary to allow them to take place' approach.

 

So take some time and work out what you need. One technique would be to draw up your diagram on a large bit of paper then get hold of some games counters / buttons / pasta shells / scraps of paper to represent trains and try simulating the moves on the plan. If a train needs to move to a particular place add the appropriate signal (main aspect or a shunt) to the plan. If you find you have two routes you now need a route indicator etc

 

It also depends on what the operators specify or ask to be included when reviewing scheme development as they know what they will want to do on the layout (usually).

[phil-b259]

 

It also depends on what the operators specify or ask to be included when reviewing scheme development as they know what they will want to do on the layout (usually).

 

Indeed - and in a way thats sort of what Chris64B will be doing. By playing around with bits of paper he can get an idea of what he wants from his model - which then becomes the operators service specification on the prototype.

[phil-b259]

Now in the garage playing trains and shunting back and forth to see how it would work. I have a thought that picks up on your last point about route indication - if a train or loco is leaving the headshunt it has a choice to enter the parcel bay or the yard, how does the ground position light signal indicate which route is set?

 

Southern region practice was to provide stencil indicators. If you have a look at the signalling plan for Crawley I posted earlier you will note that 1201 shunt signal features such a route indicator. The indicators themselves have a letter or number stencilled into a darkened filter and are backlit when the shunt signal shows a proceed aspect to light up the desired letter / number. Such indicators are relatively small (usually rectangular around 30cm wide by 15cm tall) so they may be placed in the ordinary 6ft between running lines and remain clear of the loading gauge. They can be stacked 3 high and have internal dividers so up to 6 individual routes can be shown in a stack of 3.

 

They can also be used where a main 2/3/4 aspect signal has a shunt facility attached (two white lights at 45 degrees) to give route information when he shunt signal is cleared. Again if you have a look at the signalling plans posted earlier and examine the one with T277 signal on it you will notice that T277 features a shunt signal and stencil indicator for the two shunt routes (into 2 different sets of sidings) - the feather only being used in association with the main signal aspect to indicate a route set round the branch up to another main signal (in this case a 3 aspect one).

[Chris64B]

Do you lot ever sleep?! Thanks for the overnight responses!

 

I've also found a few other useful RMWeb threads for those following and learning like me:

 

Shunting Signals - http://www.rmweb.co.uk/community/index.php?/topic/53331-shunting-signals-in-oo-gauge/

 

Stencil Indicators - http://www.rmweb.co.uk/community/index.php?/topic/77698-stencil-indicators/ and http://www.rmweb.co.uk/community/index.php?/topic/90376-dimensions-of-off-indicator/

 

Having thought about it more and placed some representative blue-tac blobs on the layout I think I'm leaning towards having three GPLs:

• One facing back into the headshunt to control exit moves.
• One facing back into the parcels bay (maybe with an NCK stencil indicator as suggested to show if route was set to main line or headshunt).
• One facing back into the yard access (again maybe with an NCK stencil indicator to show if route was set to main line or headshunt).

That way both points can be worked by signalbox/motor and I don't end up cluttering up a small area with loads of GPLs (it saves a bit of cash too if I decide to get them all working!).

 

Am I right in thinking the reason these are red/white rather than yellow/white is because of where they are positioned, i.e. if the signal is on then the points are against you so can't be crossed even if you wanted to during a shunt? The yellow/white would only be suitable if placed inbetween the headshunt points and parcels/yard points?

 

Hopefully this still works while taking on board all your advice and suggestions, so....howzat?!

 

 

Cheers,

Chris