> One obstacle is that trains vary in door positions or widths. How would you solve that problem without buying entirely new rolling stock with a uniform door l

> One obstacle is that trains vary in door positions or widths. How would you solve that problem without buying entirely new rolling stock with a uniform door layout? It doesn't have to be fancy. Chain link fencing with rolling gates can be made just about any size. You could either have the gates on motion/object sensors so they only opened when a train was at the platform and stopped, or use the low-tech method of just hiring some guys to open and close them by hand. In any case, you could get by for a hell of a lot less than $54 million bucks per station.