The T28 Gun Motor Carriage was a prototype self-propelled gun that was developed by the United States during World War II.


The basic mechanical components came from the T23 Medium Tank, and a large 105 mm high velocity gun with a range of over 19.3 kilometers was mounted in an enormous mantle, with 20 degree traverse.

Onboard ammunition storage for this gun was sixty-three rounds, and to protect the tank, the maximum armor was 305 mm thick, making it one of the thickest armored vehicles of the war. However, thanks to an underpowered 410 hp Ford GAF engine, this limited the maximum speed to 12.8 kilometers per hour. One of the most interesting attributes of this vehicle is the inclusion of two sets of tracks, rather than just one set.

The outboard set was removable, to reduce weight and width for rail travel. When removed, the extra set could be linked together, and towed behind the vehicle. The T28 also had a crew of eight and had a total weight of 86,182.5 kg.[1] The length was 10.5 meters and the width was 4.3 meters.


Only some three (the exact number is unknown and debated by historians, numbers ranging from two to five) pilot models were produced, and one of them blew up during trials. After the project was cancelled, it was believed that the other remaining prototypes were scrapped, but in 1974 a surviving example was found in a field at Fort Belvior, Virginia. Where it spent the years between 1945 and 1974 is a mystery. The GMC then was donated to the Patton Museum.


T28 tracks2

One of the few known photos of the vehicle with the outboard set of tracks removed

Since American Forces were expecting heavy resistance at the German Seigfreid line, and in preparation for the attack on it, a new heavy tank capable of assaulting heavy fortifications was to be designed.[2]

Technically, the new vehicle was not a heavy tank at all, but rather an assault gun. Late in World War II the designation was changed to T95 Super Heavy Tank, but after the war the name was changed back to T28 GMC. After the T29 Super Heavy Tank finished development, which was much more mobile, and housed the same gun in a rotating turret, the T28 project was dropped.