Cologne-Frankfurt is the other big one: https://en.m.wikipedia.org/wiki/Cologne–Frankfurt_high-speed_rail_line https://en.m.wikipedia.org/wiki/Cologne–Frankfurt

Cologne-Frankfurt is the other big one: https://en.m.wikipedia.org/wiki/Cologne–Frankfurt_high-speed_rail_line https://en.m.wikipedia.org/wiki/Cologne–Frankfurt_high-speed... Cause Laufthansa a while back to stop flying between Cologne and Frankfurt, instead they’ll sell you a seat on the ICE train (code share) with full protection for your connecting flight.