The SM03 was a two-axle shunter that was slightly heavier and significantly more powerful than the SM02 and was called the Ls150 or 2D by the manufacturer. It was initially made by Fablok and was powered by a six-cylinder diesel with 150 hp. Like many larger shunting locomotives, it had hoods of different lengths and a driver's cab with generous glazing. In the first series, the mechanical transmission had only one gear2q1 and limited the top speed to exactly 25.7 km/h. Later, another two-speed gearbox was used, which allowed the same speed in first gear and 45.8 km/h in second gear. The PKP procured a few more machines than from the SM02, but only used them to move other locomotives and passenger cars due to the limited capacity. The remaining machines were bought by the industry, which found a wide range of tasks for them.
The locos' nicknames were “Kogucik” and “Kaczka”, meaning “chicken” and “duck”, alluding to the small size and the looks. Since 1965 it had also been built by Zastal in Zielona Góra and a total of 273 units were built by 1969. The further development Zastal 409D was also developed by Zastal. A license-built Henschel 14H6 was used as the engine, which produced 180 hp. These locomotives were built by Zastal until 1978, then by Mystal in Myszków until 1989 and then by ZNTK Olesnica until 1995. The 409D was only used by private operators and not by PKP. A few examples of the locos can still be found in commercial use in the 21st century and some have been preserved for posterity.
