T-55 with BTU-55
The T-54 series tanks first appeared in 1949 as replacements for the T-34 tank of World War II. The first T-54 prototype was completed in 1946 with first production beginning in 1947. The T-54 was continuously improved and modified, and, when sufficient changes had been made, the tank was redesignated T-55. The T-55 was introduced in 1958 and incorporates all the refinements and improvements of the fully developed T-54 series without being radically different in design or appearance. The T-55A appeared in the early 1960s. Production continued in the Soviet Union through 1981 and was also undertaken in China (as the Type 59), Czechoslovakia and Poland.