Uknown Railway Operating Battalion in North Africa 1943

Anyone know what unit this is ??

Photos of five men of the "Best" railroad crew in the US Army in North Africa, 4-13-1943, all named on the back.
Photo is by or from Pfc. Jack W. Smith who was from Dennison, Ohio, and who served in a US Army railroad unit in North Africa, Sicily, Italy, and France in WWII.