Train Bridge?

Question

Who knows how to control a train bridge up ontop the watchtower?

Answer 1

Sounds like you may be asking about the controls for railroad draw bridges, swing bridges, or lift bridges.  Most are electrically powered, and have electrical controls located on a control console in a secure location.  Nowadays many if not most are remotely controlled using closed circuit TV, so that a single operator in a remote city can operate several bridges.

In that system, the bridge is left open and the railroad signals are set to STOP.  When a train approaches, needing to cross the bridge, the operator uses the TV cameras to make sure there are no ships approaching.  If the waterway is clear, the operator sounds a warning horn and then lowers the bridge.

When the bridge is down and locked, the signals change to PROCEED, and the train can cross the bridge.  The operator receives a message when the train has passed, and raises the bridge.

So there usually isn't anybody in the "watchtower."  Just TV cameras.

Answer 2

I can give you one example of a swing bridge which used to exist on the line across the River Severn in England. The bridge had a signal box on a gantry over the top and an engine beneath which was used when the bridge swung.

There were always 2 men on duty: 1 to operate the signal box and the other to mind the engine.