[majewsky]

Only for busy point-to-point connections. You can bundle up wagons from different senders or for different recipients into one train for the bulk of the journey, but the first and last leg are often done by truck because it's more cost-effective than running trains with just one or two wagons from/to individual factories.

Now if you had a train network with autonomously driving wagons that self-assemble into convoys, that would be quite something (and probably more cost-effective than truck convoys in the long run because the lower friction of metal-on-metal compared to rubber-on-asphalt).