Their distinctive cab design has led to the nickname "Brejlovec" ("Goggles").

In 1974, after the evaluation of the newly built T499.0 prototypes and considering their high weight and complexity, the Federal Ministry of Transport of Czechoslovakia sent a request to the ČKD design bureau to make a project of a locomotive similar to Class T478.3, but equipped with electric train heating generator.

More locomotives were ordered, but the manufacture was terminated by a deliberately-set massive fire that destroyed the ČKD diesel engine plant at Smíchov district in Prague in 1980.

Since the main line electrification quickly progressed in the years following their manufacture, their importance somewhat decreased in the 1990s.

The series production locomotives remain in passenger operation until today (2020), some of them were withdrawn after accidents or fires.