Just look on EU railways regulations - they are huge and with lot of strange old technologies, because, when each country enters union, conducted long negotiati

Just look on EU railways regulations - they are huge and with lot of strange old technologies, because, when each country enters union, conducted long negotiations, some things country adapted to EU, for others, EU added new things in EU regulations. Same thing with border control, every country made it considering its own traditions, practices, resources, and I think only exception exUSSR countries, which was used to totalitarian measures and used EU help to implement all new from scratch.