Is this with the Exeter to Paignton route? I’d imagine you have to use the normal keyboard T, as there doesn’t appear to be a working button in the cab: https://cdn.akamai.steamstatic.com/...uals/The Riviera Line Manual.pdf?t=1486648402
On a real 143 the Guard used to open the doors and then close them TS2022 does not have this feature and like most other stock the Driver uses the T button - the virtual guard then closed them
