The M40,9** subseries was provided without boiler for train heating.
These locomotives have been used for heavy shunting service in the Zahony area
since 1966. Originally, M40,901-905 were normal gauge locomotives, and 
M40,5001-5008 were made for 1524 mm gauge. Later, between 1974-1976,
M40,5001-5008 were transformed to normal gauge, and got new numbers M40,906-913.

Photo: Peter Werner Groh (groh@ludens.elte.hu)