I'm going to surmise your problem is inside the train as well.
You said the speedo needle and odometer both do not work together, which leads me to believe the cable is not turning. Inside the speedo head, the needle is a magnetic drive while the odometer is a gear driven system right from the cable. Even if the needle was stuck the odometer should work if the cable was turning.
You could test that by hooking the end of the cable (after pulling it from the trani connector) and chucking it in a drill and see if it works then.