parliamentary train (plural parliamentary trains)
- (rail transport, Britain, chiefly historical) Originally a requirement in the Railway Regulation Act 1844 for railways to run at least one train a day each way, at a cost to passengers of no more than one penny a mile, on every railway line in the country. Presently the term is used for passenger trains that serve a line or station only once a day or week to avoid the cost of applying for closure.
2012, Andrew Martin, Underground Overground: A passenger's history of the Tube, Profile Books, →ISBN, page 34:
He [Gladstone] also required the operators to run 'Parliamentary Trains' - one each day calling at every station at a fare of not more than a penny per mile for Third Class.