The Gulf Single Dome No. 6025 was produced between 1956 and 1958. Early issues have bar-end trucks usually with tabbed couplers and those produced in late 1957 and 1958 have early AAR trucks with disc couplers. The "GULF" emblem was applied with a two step rubber-stamp process with the background color either RED-ORANGE or ORANGE and then was stamped again with WHITE and NAVY BLUE. There are five varitations:

Variation A: BLACK tank that has WHITE lettering with RED-ORANGE background with WHITE "GULF" letters over NAVY BLUE. Came with bar-end trucks with tabbed couplers.

Variation B: BLACK tank that has WHITE lettering with ORANGE background with NAVY BLUE "GULF" letters over WHITE. Came with bar-end trucks with tabbed couplers.

Variation C: Painted BLACK tank that has WHITE lettering with RED-ORANGE background with NAVY BLUE "GULF" letters over WHITE. Came with AAR trucks with disc couplers.

Variation D: GRAY tank with BLUE lettering and either an ORANGE or RED-ORANGE background with WHITE "GULF" letters over NAVY BLUE. The body of this car is not painted, but it is sometimes found with painted end tank caps. Came with AAR trucks and disc couplers.

Variation E: ORANGE tank with BLUE lettering and either an ORANGE or RED-ORANGE background with WHITE "GULF" letters over NAVY BLUE. Came with AAR trucks and disc couplers.