Definition of "unimposing"

Melton Mowbray station, ½ mile east of the junction, is an unimposing and cramped structure with up and down platforms only and express trains which call there have to draw up twice because of the short platform lengths.

1959 June, J. F. Oxley, D. R. Smith, “The Nottingham-Kettering line of the L.M.R.”, in Trains Illustrated, page 320