From a train point of view those wheels will fit happily within the guides of the bridge, and the connections on the tracks should just about fit as well.
I'm fairly sure we bought our bridge when we were staying in a holiday cottage that had a load of the old black track, and it connected to the track successfully, but you may need to work with some curves ...
There are numerous solutions over internet for attaching SG90 servo with LEGO. However I remember this particular video, which fit your need to attach/control Technic beams/liftarms. It also features required parts for this build at 7:48.
For this experiment we're using the wheeled Duplo push and go motor block and red cabin from Set #10874.
The wheel width of the motor is the same width as a non motor base.
So, for this train to stay on the six stud track, the wheels need to sit either on the inside of the tracks or the outside of the tracks.
As the last picture shows, the wheels ...