PKP class SM04

Built between 1972 and 1978, the SM04 differed from its predecessor in that its construction allowed for the installation of a more powerful diesel engine, built under licence from Henschel. Originally, this engine was to be the 10H6, which had a power output of 160 bhp; however the 180 bhp 14H6 was used instead.

The SM04 was mainly sold to industry, where they carried their factory designation of 409Da. A mere 2 examples were acquired by PKP at the beginning of the 1990s. Both locomotives had been salvaged from Zakłady Naprawcze Taboru Kolejowego w Sędziszowie (Sędziszów Rolling Stock Reparation Plant), but were removed from PKP's inventory in 2000. One of these is now stationed as an exhibit at the railway museum in Chabówka.

• Polish locomotives designation