The lights - front and rear - do not come on (realistic mode):
After activating the switches on the dashboard in the cab view, you will notice that the lights remain off in the exterior view ; the same applies when turning them off: return to the cab, set the switches to the desired position and wait two seconds.
When the session starts, the train is silent, with no exhaust smoke:
The start-up of the locomotive and coach scripts depends on the presence of an active driver (the one you designated in your session settings); the detection of this active driver is sometimes faulty (GetActiveDriver function) : if you have placed your driver in the motorcoach, click on the coach, ignore and close the blue box that appears, and click on the motorcoach, or reverse the manoeuvre if the driver is initially in the coach cab.