| T48 gun motor carriage | |
|---|---|
 A T48 in Moscow on Poklonnaya Hill. | |
| Type | Self-propelled anti-tank gun |
| Place of origin | United States |
| Service history | |
| In service | 1943–45 |
| Used by | United States, Soviet Union, and Britain |
| Wars | World War II |
| Production history | |
| Designer | Aberdeen Proving Grounds |
| Designed | 1940–41 |
| Manufacturer | Diamond T |
| Produced | 1942–43 |
| No. built | 962 |
| Specifications | |
| Mass | 9.45 t (20,800 lb) |
| Length | 21 ft 0 in (6.40 m) |
| Width | 7 ft 1 in (2.16 m) |
| Height | 7 ft 0 in (2.13 m) |
| Crew | 5 (commander, gunner, driver, loader, and a radio operator) |
| Armor | hull:6 mm windscreen visor and gun shield: 12.7 mm |
Main armament | 57 mm gun M1 with 99 rounds |
| Engine | White 160AX, 386 in3 (6,330 cc), six cylinder, gasoline, compression ratio 6.3:1, 128 hp (95 kW) |
| Power/weight | 15.8 hp/ton |
| Suspension | Half-track, vertical volute springs |
| Fuel capacity | 60 US gal (230 L) |
Operational range | 150 mi (240 km) |
| Maximum speed | 45 mph (72 km/h) |
The T48 57 mm gun motor carriage was a self-propelled anti-tank gun produced by the Diamond T company in 1943 for the United States. The design incorporated a 57 mm gun M1, a US production of the British Ordnance QF 6 pounder, mounted on an M3 half-track.
A total of 962 vehicles were produced from 1942 to 1943. It had originally been planned that Britain would receive all of the examples produced through Lend-Lease, intending to use them in the Western Desert, but by the time they arrived the campaign was over. Additionally, the purpose-built M10 tank destroyer, armed with a 3-inch gun (and later a 17-pounder gun in British service) had begun to enter production. As a result, the British transferred 650 half-tracks to the Soviet Union under the Soviet Aid Program. Britain retained 30 and the remainder were taken by the US; except for one kept by the U.S. Army, these British and American vehicles were converted back to standard M3 half-tracks.
The Soviets called it the SU-57 (Samokhodnaya ustanovka 57); under this designation it served in Operation Bagration and other fighting on the Eastern Front during World War II.