Take a look at the image above. This rendering represents modern bus rapid transit service. The BRT vehicle travels in its own separate lane, free from the constraints of traffic congestion or traffic lights. The bus is sleek and the shelter is pleasant. If you could see the boarding procedure, too, you'd find that passengers buy their fares ahead of time, enabling them to enter quickly through any door, just as they do on a train.
Now take a look at the image below, which shows a modern light rail service. The scenes are remarkably similar. This train travels in the same dedicated lane and even has the same style. The only real difference you'll find, if you look very close, is the faint sign of tracks on the ground.