wheelbase

noun

1. The horizontal distance between the front and rear axles of a road or rail vehicle.

   “Beneath the snow, and after we had left it behind, the road was as greasy as vaseline, as steep as a scenic railway, and often not a yard wider than the lorry’s wheelbase.”

   “The Southern acquired them because the little Class "B4" 0-4-0 tanks were finding heavy modern rolling stock more and more of a handful, and at war's end the railway had nothing of suitable power but short wheelbase on its books to take their place on the more tortuous of the dock lines.”

   “He thought the types of wagons planned (short-wheelbase types) needed reassessment.”