1) our train length is limited - see the parallel comment. UIC limits our trains to 750m top, we don't have the space required for train yards that can handle longer trains, and the signal blocks are too short apart to handle trains longer than that (basic railway safety, a train must always have enough free space in front so that it can brake from full speed to zero in case of crossing a red light without crashing into the train in front). US trains run in multiple kilometers of length, so they have vastly greater capacity.

2) our car height is limited because our networks are largely electrified which means you can't double stack containers on them

3) our infrastructure is densely packed which means that you can't just run a train uplink to a random warehouse, and for those industries that do have a train uplink, the shunting required is expensive (need to maintain locomotives and trained drivers, which are in rare supply compared to truck drivers).

> Being government subsidised, often nationalised, there's no innovation anywhere, nobody cares, all the usual problems of socialised infrastructure

WTF? That's just flat out wrong and ideological. There is no real innovation anywhere in railways, the only thing that the US makes different is that freight trains are prioritized and longer, but that's hardly innovative (and again, as Europe is smaller and denser, impossible to replicate).

With smaller innovations (I'd call these "improvements") the situation looks different - e.g. the digitalization of train control aka ETCS, automated couplers, more efficient/silent braking systems... the tech exists, vendors exist - but good luck getting all the private freight companies to on-board to that new tech, as they don't want to bear the cost of progress! That, and solely that, is why Europe is still stuck with screw couplers and dumb freight carriages.