A Channel Tunnel in 1905

How would a Channel Tunnel opened in 1905 affect German strategy in World War I?

German planners are still expected to underestimate British intervention, with the tunnel terminus becoming an important objective and rail capacity governing reinforcement.

A Channel Tunnel opened in 1905 would provide a direct railway route for British troops and supplies. German planners are still expected to underestimate British intervention and overestimate the time available for their own campaign. The continental terminus matters: a Belgian exit would place reinforcements directly in Belgium, while Calais would become a more important objective if the tunnel ended there. The rate of reinforcement would then depend on how quickly trains could run through the link. A later war would make the tunnel and its exit another major defensive problem.