To convert the locomotives to the 749 class, the steam boiler was removed, and replaced with an alternator to provide electric train supply for heating.

The final locomotive was additionally modified with a new electrical control system.

At České dráhy several locomotives are still operational at Prague's Vršovice depot, working weekend services to Čerčany.

The prime mover is a ČKD K 6 S 310 DR, a four stroke, six cylinder diesel engine, fitted with a PDH 50 V turbocharger.

[1][3] All four axles are fitted with DC traction motors, manufactured by ČKD.