The level of the technical state of the steam locomotives 404.0 was becoming lower and lower. The resolution to electrify the track was abandoned and the new decision for the diesel traction was made. Keeping in mind, that the development of such a type of locomotives would have a big demand both for finance and time, the new locomotives were ordered at austrian company SGP and the machines were delivered in 1962. At ČSD the become the serie T426.0 .

The new engines were quite unusual, in the mater of fact they were prototypes, the ÖBB had only one piece of this type. The diesel motor was one with the performance 1100 HP.

The locomotives had 2 hydrodynamic gearbox, one with the max. performance transfer 742 HP to the adhesive wheels, the second with max. performance transfer 283 HP to the cog wheels.
(For the later born people: 1 HP= 0,73549875 kW)

 
Let me use the very smart web page " 50 let motorových ozubnicových lokomotiv T426.0" from the author with the signature Lajos (btw railtrains.sk web site administrator) like the picture presentation.