Steam Operate Br 218 Cab Car In Free Roam

When spawning a BR 218 with N-Wagen and CAB Car, I cannot manage to drive with the CAB Car. Driving the same train with the loko is fine. KWS Remote Control is switched on. What are the steps to start the train directly from CAB Car in free roam mode? I think the loco is already geared up?

 

You may also need to set the 218 to KWS mode

 

Thanks very much, that's what I've missed!