I have the Veto Pro Pack which is not a rolling bag, so when I need to take it further than I want to carry it I use a generic folding two wheel cart.
It is not ideal because you can't easily get into the bag without taking off the cart, on the other hand you can use the cart for other things and you can also stack items on the cart and put the Veto Pro Pack on top of them. Also the cart is relatively cheap.
A more Festool-ish solution would be the Sys-Roll but this might be a bit bulky for the train, also much more expensive and mainly designed for Systainers, although it can certainly carry other things.
Jeff