6Dm

6Dm-01 from the Oriom Kolej fleet, photographed at the Kłodzko Główne station on December 2, 2016, by someone who wishes to be known as milek4 (source: www.commons.wikimedia.org).

6Dm-02, photographed between Nowy Sącz and Stróże on March 28, 2025. Source: www.orionkolej.pl.

SM42 switcher from Fablok (factory type 6D, designated Ls800 with some industrial operators) remained in production from 1964 to 1992. Total output, including versions with car heating equipment SP42 and SU42, exceeded 2000 examples. Most of them still remain in use with PKP, industry and private operators, despite obsolescence of the basic design. Since late 1990s several modernization packages have been proposed. All of them included diesel engine replacement, as the original a8C22 unit is, by modern standards, uneconomical, heavy and environmentally unfriendly. Some included also extensive modification, leaving little more than frame and wheelsets unchanged. What finally resulted was in fact a new locomotive and these variants are described under separate entries. The most numerous of these modified versions is type 6Dg from Newag, of which 170 examples have been delivered, both for PKP and private operators.

The least known 6D modification is type 6Dm from Orion Kolej. This company, based in Nowy Sącz, was founded in 1997, initially as a locomotive repair shop. Later it gradually extended its activities, entering motive power leasing business and acquiring a number of second-hand locomotives. One of them was SP42-173 (Fablok 9365/1976) from PKP Cargo, purchased in January 2010. Modernization of this locomotive at the company’s own premises was completed in April 2015 and basically followed the 6Dg variant, with the same Caterpillar C27 diesel engine rated at 875 hp and electric equipment. The body is slightly different, especially front and rear walls and cab roof, which is less angular. Re-numbered 6Dm-01, this locomotive joined the Orion Kolej fleet in September 2016; in 2020 it was leased to LTE Polska. Second conversion, of SM42-690 (Fablok 9025/1974, withdrawn from PKP Cargo in September 2015), followed in February 2025. This locomotive remains the Orion Kolej property and was exhibited at the TRAKO fair in Gdańsk in September 2025. Until now (February 2026) no more examples have followed.

Main technical data

No.	Parameter	Unit	Value
1.†	Years of manufacture	-	2015 – ^1)
†2.	Total built / used in Poland	-	2 / 2^2)
3.	Axle arrangement	-	Bo’Bo’
4.	Transmission type	-	electric
5.	Design maximum speed	km/h	90
6.	Prime mover type	-	Caterpillar C27
7.	Engine rating	kW/hp	652 / 875
8.	Bore ´ stroke	mm x mm	137 ´ 152
9.	Number of cylinders	-	12
10.	Number of electric motors	-	4 ´ LSa-430
11.	Rated output of electric motors	kW	4 ´ 173
12.	Main reduction gear ratio	-
13.	Diameter of drivers	mm	1 100
14.	Total weight	kg	74 000
15.	Axle load	T	18.5
16.	Axle base	mm	10 100
17.	Overall length	mm	14 240
18.	Maximum width	mm	3 120
19.	Train heating	-	-
20.	Brake type	-	Oerlikon

1) SM42 and SP42 conversions.

2) Until February 2026.

References and acknowledgments

- www.orionkolej.pl;

- www.kolejowaklatka.org (website by Marek Dąbrowski);

- www.ilostan.forumkolejowe.pl.