Yes, there are typically a lot more trains active than stations, so many of the lights would be lit up nearly all the time if you tried to represent each individual train. Some lines (Victoria) actually have more trains in service than there are platforms during peak times.

It would be neat if you could say highlight a certain route or two and have a different coloured led show it transverse the line. That way it is not so cluttered with all the other trains but informative to the individual.