[sofixa]

> Whereas on the Continent, trains regularly cross between countries and the whole system is much more-but far from entirely -integrated, politically and physically

That's not true. There are some local connections and integrations, but outside of high speed rail which is generally built using the same standard, each country has their own load gauge, electrification standard, signalling system, etc. Cross-border trains are usually special traninsets built to multiple standards to be compatible.

There is progress on more integration and standartisation, and pretty much all new lines are built to the same standards, but the vast majority of rail is existing.