Berth to signal mapping at a bay platform

[Norbert M]

I have stumbled upon interesting example of a bay platform scenario at Stratford and cannot work out how would you link the berth step to the change off signal in the situation where there isn't (at least I cannot see it) a specific signalling mapping in the TD spec file that would correlate to TD "from berth" that starts with A*** letter, in this case at platform 1. All signals and TRTS look to me as S1404 and L1404TRS records in the TD spec. Would just the time window will be enough in such a situations to work out the signal change for a particular headcode stepping from berth 'A404' at platform 1? I have made a little view of the situation based of the https://www.opentraintimes.com map and rail-wiki.

Thanks for any answers and best regards,

Norbert

[Peter Hicks]

Hi Norbert

On Monday, 29 September 2025 at 13:09, Norbert M <mal...@gmail.com> wrote:

I have stumbled upon interesting example of a bay platform scenario at Stratford and cannot work out how would you link the berth step to the change off signal in the situation where there isn't (at least I cannot see it) a specific signalling mapping in the TD spec file that would correlate to TD "from berth" that starts with A*** letter, in this case at platform 1. All signals and TRTS look to me as S1404 and L1404TRS records in the TD spec. Would just the time window will be enough in such a situations to work out the signal change for a particular headcode stepping from berth 'A404' at platform 1? I have made a little view of the situation based of the https://www.opentraintimes.com map and rail-wiki.

Don't rely on a time window for this situation - you'll need to look in to the TD stepping table to see the conditions under which a step from B404 to A404 occurs. Usually this will be clearance of the signal, but on some TDs, it could be when a route is set.

Can you give some more information on what you're trying to work out here?

Peter

[Norbert M]

Thanks Peter for a quick response. I am trying to work out the signal clearance and TRTS times for the headcodes departing from P1 and P2. 

Setting correct S-Class bit mappings is the challenging part at this situation. I haven't noticed the step from B404 but will look into the data again  - thanks for the directions.