They are for use when entering a terminating station/platform . Basic UK 3 aspect signalling works on the principle of Red aspect to Yellow aspect then Green .
The bufferstop at the end of the line is classed as the red aspect (carries a red light on passenger lines) so you would only expect the driver to receive a single yellow aspect before entering the terminating line as a warning that the signal (buffer stop) is showing a red (stop) aspect.
The 2A terminating signals only show show a red aspect or yellow aspect . It doesnt show a green aspect as it would never be used.
The 3A terminating signals would be used on lines signalled with 4 aspect signalling . This would be placed as the signal before the 2A terminating signal . This signal is only capable of showing Red / single yellow / double yellow (see below)
3A terminating signal ======2A terminating signal===platform=Bufferstop (with red light)
The driver would receive 2 yellows (meaning next signal 1 yellow)======== 1 yellow (meaning next signal is displaying red) ==== Bufferstop showing a red light (stop)
On to the next problem:
I've been away from TRainz from sometime and now I've returned to use TRS 2009.
I've previously used the "Advanced Signalling Pack" quiet a lot and made use of the "caution" and "call-on" fucntions for junctions.
Either I've totally forgot about how to make it work or the scripts for these functions must be broken. I've played aroudn with the functiona and the reset trigger and just can't get to work at all. :'(
They work fine as usual signals tho...
Am I just stupid or are they broken? If they are broken, have anyone come up with a fix/patch?