Off the top of my head I can't think of any European railroad concepts besides superheating and Walschaerts valve gear that caught on here.
The Belpaire firebox seemed pretty popular on the PRR and Great Northern and I think Brooks built quite a few locomotives with Belpaire boilers for many other roads.
There was Stephenson valve gear, bar frames (originated by Stephenson), the fire tube boiler, the Giffard injector.....
Peter