milk train

Familiarised from the early morning goods trains used to transport milk on the British railway system.

milk train (plural milk trains)

1. (UK, colloquial) A slow passenger train leaving in the early hours of the morning.
   • 2012, Pete Townshend, Who I Am, HarperCollins, →ISBN, page 245:

     But I also felt again the remembered romantic warmth of nodding off on the milk-train home in the early hours, with Liz by my side.

2. (rail transport) A goods train that carried milk, usually in tank wagons.
   • 1959 March, R. C. Riley, “Home with the Milk”, in Trains Illustrated, page 154:

     On the Western Region, milk trains work up to London from Penzance, Wellington (Som.), Weymouth, Whitland, Carmarthen and Wootton Bassett, each train making several intermediate stops to attach further milk tanks, and in some cases to shed them.

• British railway milk trains on Wikipedia.Wikipedia

• Kilmartin