On the MoPac, a select few GP7's had a 'crew cab'. These units were originally on the Texas & Pacific and Gulf Coast Lines. Outwardly they looked like any regular Geep with the exception that the crew-cabs were modified with an extra set of number board cut-outs/windows that were exactly the same size as the number boards located just below the usual number boards on the short hood/nose. Behind the windows inside the cab sat a spare seat... right beside the typical toilet. The 'crew-cab' GP7s used by I-GN and STLB&M (series 4116-4123) were equipped with crew-cabs (modified circa 1953): 4117, 4119, 4120, 4122, and 4123. Since no other unit's received the crew cab, it's speculated that this modification may have been a 'Texas thing' for the brakeman to ride inside the unit.