How much would a modern twin-track Channel railway have helped Allied logistics in 1944?
Short answerIt would make a major difference by moving divisions and heavy equipment directly by rail, while leaving marshalling yards, locomotive handling and traffic priorities to manage.
NotesA twin-track Channel tunnel after the Normandy landings would let complete divisions cross by rail without unloading their equipment onto ships and loading it again in France. Heavy armour and specialist vehicles would benefit, including equipment otherwise dismantled for transport and rebuilt on arrival. Marshalling yards and locomotive handling would still limit throughput, although these would be less severe constraints than temporary or captured ports. Rapid movements, including formations and fuel, would take priority, while food, general stores and possibly ammunition would continue by sea. Ammunition raised the additional concern of an explosion inside the tunnel. Electric haulage is preferred because of the tunnel's length, though the claim that steam operation would be impossible draws disagreement. One proposed arrangement keeps the original locomotive with its train, drops its fire before entry, and uses an electric locomotive to haul the whole train through before the steam crew relights the fire in France.