I just assumed railway movement was considered in the movement. Those are pretty large distances to cover and it was still the era of steam, not bullet trains.
German armor, especially heavies mostly moved by rail since long road marches were hard on equipment.
It is a good point regarding different scales of rail though. Perhaps a movement penalty where armor can only move 1 on foreign soil (excluding Africa). That reflects rail movement.
Personally, I think blitzing is too powerful anyway. Maybe for mech inf as a fast moving scout, but not armor later in the war.
Yes, Blitzkrieg in France, but that was lightly armored fast moving tanks that wouldn’t survive once T-34s were on the battlefields. Bad roads, long distances and formidable opponents cut that out. US was bogged down in Normandy fight through hedgerows and ran into problems after since French rail was decimated in bombing.