One principle difference is that the rails and momentum dictate where you go. All you can do is gradually speed up and gradually slow down. They have between 2

One principle difference is that the rails and momentum dictate where you go. All you can do is gradually speed up and gradually slow down. They have between 2 and 4 tracks on that corridor and they dont necessarily stay on the same one during the entire trip. You need to make sure you are on the correct track. You have to radio in at specific markers to let the controller know where you are. If you fail to radio in, they might assume you're AWOL and order an emergency shutdown of neighboring trains. You have to make sure you have a green light for the particular track you're on at every signal. Tracks are a scarce resource, if you go too slowly or make a mistake, you are delaying every train behind yours (times the hundreds of people in each one). You need to use energy efficiently: too much juice and you will grind the wheels, or waste energy by not accelerating at the optimal rate or braking un-necessarily. You have to control your speed exactly for the particular section of rail you're on.