The D.345 is a diesel-electric locomotive that was mainly built for freight service and introduced simultaneously with the D.445 passenger locomotive. Compared to its sister, the D.345 is much lighter, has an engine with only 1,350 hp and no electric power supply for passenger trains. The hourly output of the traction motors is 1,020 hp in total. With an axle load of only 15.5 tonnes, it can also be used on branch lines.

Nevertheless, these locomtoives also have a top speed of 130 km/h and were sometimes used in passenger service together with generator cars. Each bogie is being powered by only one traction motor that transmits its power on both axles. Later they were only used in freight service and from 2009, maintenance was reduced to the bare minimum. By 2017, their number had been reduced from 145 to 39.