Here's something for consideration; given that we will very soon have the capability of transport by flight (there's already designs that are bidirectionally automated - i.e. via docking stations) what are you're views as to the longevity of implementing railway systems (especially large scale)?
IMO it's going to come down to a basic evaluation: speed v resource spend.
I suppose it may be difficult to implement a dispensing system (actually I can already think of a few ideas for that - maybe not so bad really). Is this something to be considered for future iterations of SG?