Plenty of Traxx, Vectron etc owned by leasing companies and working throughout mainland Europe. The main obstacle is incompatible signalling systems but this will gradually solve itself as more lines are fitted with ERTMS.
Also true on the passenger side, the Stadler FLIRT being an example where very similar units are operating in several countries. And closer to home the Eurostar e320 is the latest version of Siemens's high speed Velaro which is derived from the German ICE.
There will be greater or lesser degree of design variations between individual production runs of these, but the basic design is the same and this not only realises economies of scale but avoids the sort of novel features that tend to introduce unreliability.