There are two binding posts at one end of the station - look at that end.
The right post is ground, the left is hot.
One post wire(usually the ground) goes to one of the motor brushes, the other brush is connected to one of the field winding wires. The other post wire(usually the hot) goes to the remaining field wire.
Hooking up to any small 25-50 watt transformer will run the motor. It should be lubed(oil the armature shaft bearings). Put a momentary NO(normally open) switch into one of the transformer wires to operate the whistle when pushed.