M4高速拖拉机走

The M4 High-Speed Tractor was an artillery tractor used by the US Army from 1943. The M4 was based on the chassis and drive train of the obsolescent M3 Light Tank which introduced the trailing idler. This common practice of re-using old vehicles simplified design, allowed for easy production, and made maintenance in the field easier.

资料来源： M4高速拖拉机上的维基百科