There are many suitable timer relay modules that I think will do the trick. In the video below, the station stop zone is the single track section with the white-paint. This is just a proof of concept - a station stop zone would no doubt be much longer. I didn't have a trolley to play with so just used a powered motorized truck (co-opted from a twin-motor diesel) with a bridge-rectifier to convert track AC to motor DC; the motor is locked-in-forward so to speak. There is also a white LED on the truck to show when power is applied to motor.
In this example, the timer module shown above is set to Mode P-2, CL time of 7 sec, OP time of 3 sec. Normally there is no track power in the station zone. When trolley enters the stop zone, the timer module is triggered. This starts a 7 second (CL) delay which is the station stop time; the relay is OFF. Then the relay is ON for 3 seconds (OP) which powers the station zone so the trolley can leave the station and reach the powered track.
Note that if the station stop zone is too short and/or the trolley enters the station too quickly, it can coast through the unpowered station zone and reach the other side and continue on without stopping.
The key to this method is tying the DC common that powers the DC-timer-relay module to the AC common that powers the track.
If there is any interest, I can provide additional details and comments.
