In an attempt to assist in solving the branch line problem, Major Frank Dutton, SAR Signal Engineer and the Motor Transport Superintendent, developed and took out several patents on a loco-tractor system. The aim was to replace or eliminate the steam locomotive on non-profitable branch lines since he considered the locomotive to be the main deciding factor on the questions of grades, curves and weight of rails, which governed the cost of construction.Patent: Dutton Light Railway System and Locomotive Therefor, US 1306051 A, Jun 10, 1919Patent: Locomotive for light railways, US 1416625 A, May 16, 1922Patent: Vehicle for Service on Roads and Rails, US 1561510 A, Nov 17, 1925
