Comment by bahmboo

5 hours ago

Nice find. The gap in the Spanish track is massive. I don’t know enough to speculate on technical reasons but it seems quite odd.

Rails expand and contract according to the temperature (11mm per degree C per km). They are continuously welded together and installed under tension and heated to a neutral / median temperature for the location. It was around 0C that night in an area that gets up to 47C (and rails might get hotter under the sun) so there was at least 300mm of contraction per kilometre of rail.