[3] 2 prototypes were built between 1974 and 1975 by ČKD Praha, who leased the locomotives to ČSD.

[1] The locomotives were initially tested between Prague and Ostrava, working the express train Ostravan.

[5] The two where then purchased by VÚŽ (Výzkumný Ústav Železniční), the Czech Railway Research Institute, and moved to the Velim test circuit.

[5] The first locomotive was used as a spare parts source for the second, and was eventually used for crash tests, then scrapped.

[6] In December 2012, the second locomotive was moved to DPOV's Nymburk works for a return to operation,[7] with adaptations being made to overcome the initial reliability problems, including the fitting of an entirely new electrical control system.