the.com/ghost train

means A scheduled train or bus service that runs empty or nearly empty, often kept on the books for regulatory or technical reasons rather than to actually move people.

from A straightforward compound of 'ghost' (something present but unseen, insubstantial) and 'train.' The term rides on the old sense of 'ghost' as a thing that exists in form but not in substance — a service that haunts the timetable without carrying the living. In the UK it also picked up a specific technical use: railway companies keeping a legally required service running by scheduling a train so inconvenient or obscure that almost nobody rides it, purely to satisfy the paperwork needed to close a line officially. The phrase is also sometimes used loosely for abandoned or disused rail lines said to be haunted, but the transit-jargon sense — empty service, present only on paper — is the one that stuck.