This is a short story I read in the late 80s. A soldier called H leaves an embattled position near a time-rift battlefront where humanity and unidentified aliens are shelling each other to prevent a crossing.
He is going on leave to see his family and travels on a series of carriages like train compartments, crossing with other travellers. As he travels back in time his name, H, expands to Had, then something like Hadril and so on until he reunites with his family. He's then suddenly recalled to action.