Do you mean make sure that they are trained Colin?
teddy
No! In all seriousness you could have one car at the front with a really large engine then a lot of cars all joined together and pulled by the lead car so these other cars would not need to have their own engine you could just use them for passengers also you could have a few cars with no seats and these could be used to carry parcels and stuff like that, you could even do away with the pneumatic tyres and replace them with steel wheels this would be more efficient as you would have only rolling friction, you do not even have to power the lead car with the old IC engine you could put overhead electricated wires over the tracks and find some way of using this, or better still you could use a nuclear powered steam engine .... for heavens sake the possibilities are endless,