UK Calling on signals

[pfx]

I'm trying to set up the calling on function on davidbird's 3 aspect BR signal with subsidiary (kuid2:195134:100140:13) without much success. I've followed the instructions with Saxham Market's permissive trigger in rear of the signal, and feathers in front, so far without any joy. The approach is on double track converging to a single line, with a running line to the left, and yard to the right. In all my attempts, the signal will update and display the right hand feather but the sub will not illuminate.

I thought I'd read a thread on this before but have been unable to find it.

Cheers,
pfx

 

[davidbird]

Hi
I've not been on here much recently.... but just found your post!
If I've read it right the layout is something like this
>---------S---------\
<--------------------\----------\-----------<>-running line
\-----------yard
The Permissive Trigger will only trigger the sub is there is 1) another train before (in rear of) the next signal (or bufferstop) and 2) there is enough room for the 2nd train to fit behind it.
If you want the sub to illuminate every time the route is set into the yard, regardless of whether it is occupied or not, you will need to use an Enhanced Interlocking Tower to set up all the routes through the junction complex and set the signal state for the route into the yard to be "Stop then continue".
In UK signalling practice there would not be a feather for the route into the yard, just the sub signal.
If you're still having problems send me a DM...
Cheers
David

 

[davidbird]

Another thing to consider with the Permissive Trigger is this. If you have 2 trains bound for the main/single line, it will trigger the sub if both will fit before the next signal, which may not be what you want.
I am using them on my wip (20 years and counting!) route which had automatic calling on signals, the Erewash Valley Up Goods between Clay Cross and Toton. I've managed a somewhat clumsy method of a very short loop of invisible track with the Permissive Trigger on it and train priority track markers so that any passenger trains do not see the PT, but goods trains do activate it.
Using the Permissive Trigger to set the stage of a signal is incompatible with using the EIT, so if any real junctions are involved it can't be used. But it is allowable to have two identical routes defined within the EIT, one with signal state "Automatic" and the other with "Stop then continue". For example it is possible to have a train running into a platform under a yellow (or even green, depending only on the section in advance) then have another loco attach to the rear under the calling on sub. It just needs the correct one of the two (otherwise identical) routes to be selected.