Tank origin

The T-55 program updated the T-54 main battle tank with a number of improvements. These included a water-cooled diesel engine, vertical and horizontal stabilization for the main gun, an infrared gunner’s searchlight, and perhaps most importantly, nuclear, biological, and chemical (NBC) protection. The T-55A, which featured additional anti-radiation shielding, was considered the final production version; it first appeared in 1963.