TGM2-003, first example built at Lyudinovo. Photo from LOZD vol.2.



TGM3 prototype; source – as above.




Side drawing of the early version (prototypes from Fablok)…




…and late production Ls750Hu. Both drawings by M.Ćwikła (source: SK vol.3/2009).





SM15-17 at the Railway Museum in Warsaw.  Photo taken on July 23, 2002.




Another picture of SM15-17, taken on May 25, 2005.




SM15-22 plinthed in Tarowskie Góry. Photo taken on   April 16, 2004.




Another picture of this machine, taken on September 28, 2005.




This locomotive, Ls750-7438 from PTKiGK Zabrze (withdrawn), was photographed by Roman Ficek in Zabrze in September 1988 – thanks for permission! (source:




TGM3-2804, photographed at the railway museum in Riga on August 5, 2002. Photo from my collection.



TGM3 remains in use in several countries; this TGM3-1400 was photographed at the Torņakalna station, Latvia, May 22, 2010, by Jānis Vilniņš aka ScAvenger (source:



TGM3-021 (Lyudinovo, 1960) from an industrial plant was transferred to the railway museum in St. Petersburg in 1996. Photo taken on October 27, 2007; source: as above.




Very few diesel locomotives with hydraulic transmission have been used in Poland. Although this concept was known to show much promise, hydraulic torque converters were demanding from the point of view of manufacture and maintenance. First experience was certainly not encouraging: few ex-German machines acquired after WWII proved in general very unreliable (but this could be attributed to complete lack of spares). The idea was, however, not abandoned and in late 1950s, when future successor of the SM30 switcher was contemplated, three examples of SM25 were built. These machines, fitted with imported Voith hydrokinetic converters, were successful, but no Polish factory was then able to undertake manufacture of transmission gears and import from Austria was out of question, so no further examples followed.

Take two came in 1963. In parallel with the 6D medium-power switcher with slow-running a8C22 800 hp diesel engine and electric transmission (which eventually became SM42), it was decided to develop another locomotive in this category, but with hydraulic transmission, on the basis of a foreign licence. The choice fell on Soviet TGM3, built by Lyudinovo Diesel Locomotive Factory (now Lyudinovoteplovoz Joint Stock Co.). Origin of this type can be traced back to 1957, when two prototypes of the TGV switcher (later re-designated TGM2 – T for diesel engine, G for hydraulic transmission, M for switcher) were built at Voroshilovgrad Diesel Locomotive Factory (now Lugansk, Ukraine). This machine, with sloping front and rear upper body panels, which gave it somehow strange – and not particularly attractive – appearance, was fitted with the M750 diesel engine rated at 750 hp. It was decided to transfer its production to Lyudinovo, but the machine displayed poor running qualities and had many shortcomings, so only three more examples were built there. Extensively redesigned variant, with completely different body, modified trucks, M751 diesel of the same rating and many minor improvements, appeared in 1959 and was designated TGM3. Production started soon and lasted until 1967, when 953 examples had been built. In the meantime, improved TGM3A appeared, with different hydraulic converter and later also improved M753B diesel (656 examples built between 1961 and 1970). TGM3B, introduced in 1966, had further improvements, concerning mainly transmission. During 1966 and 1967, all three variants were in fact built in parallel, but after 1970 only TGM3B remained, of which 1928 examples had been built until 1977. Six of them were fitted with turbo-supercharged M773 diesel engines. There were two experimental variants which were not put into production: TGM3M (modified transmission gear, found inferior to the basic variant, only one built in 1960) and TGM3O (or TGS – different transmission, unsuccessful, only one built in 1961). This gives the grand total of 3539 examples, excluding those built for export and under license. Machines of this type served with Soviet state railways, but most (2360) went to other operators, mainly industrial establishments.

In mid-1990s a number of TGM3Bs were converted into TGM4s; this variant differed mainly in new six-cylinder 211D1, 211D2 or 211D3M diesel engine, which supplanted unsatisfactory M753. Production of TGM4 started in 1971 and lasted until 2017, with total output in excess of 6500 examples. Several older examples have been modernized to the TGM4B-UGMK or TGM4N-UGMK version and fitted with the 850 hp Cummins QST30-C850 diesel engine.

Two TGM3s were purchased by PKP in early 1963 and numbered SM15-01 and SM15-02 (Lyudinovo 354/1962 and 355/1962). License agreement followed soon: SM15s were to be built by Fablok in Chrzanów (factory designation Ls750H, later 12D), both for PKP and industry. First two examples, SM15-03 and SM15-04 (Fablok 6534/1963 and 6535/1964), were completed in early 1964. Diesel engines and hydraulic torque converters were imported from the USSR, but it was intended to introduce indigenous V12CD19 diesel engine and improved hydrokinetic torque converter in next production version, designated Ls750Hu. Further variant, known as Ls750Hm, was to have been fitted with different trucks (based on that of type 6D, or SM42), but it was not proceeded with. Deliveries of new torque converters lagged behind schedule and all SM15s for PKP were fitted with old units, corresponding to the original Ls750H standard.

 In service, SM15 soon earned a bad reputation of an underpowered and extremely unreliable locomotive. Failures concerned mainly diesel engines and transmission. Until 1967, when production of this type was terminated, only 25 machines had been built by Fablok for PKP. Thirty more were supplied to various industrial operators; all but five were completed to the Ls750Hu standard. Of these, collieries and sand railways used twelve; the rest went mainly to chemical and petroleum industry. As development of the V12CD19 diesel engine was finally discontinued, only four SM15s were fitted with this power plant. Last, 55th locomotive of this type was delivered from Fablok in 1967 (s/n 7564) to a power plant in Bydgoszcz.

SM15 is one of the least successful and most obscure locomotive classes in the PKP service. All machines of this type were based in Kraków. They hauled local freight trains and were used for switching, but on occasions ran also with light passenger trains. Their availability remained very low, much due to poor quality and very short service life of the M753 diesel engine; at times almost 75% of all locomotives in service were undergoing or awaiting repairs! Torque converter efficiency was below that specified by the producer and tractive effort, especially at higher speed, was very low: some claim that above 55 km/h a SM15 could haul only… itself. No wonder, thus, that PKP got rid of these locomotives fairly soon. According to SK, five examples were written off in 1968, less than two years after last SM15s were accepted! Last two in the PKP service, SM15-17 and SM15-26, were withdrawn in early 1977. Most ex-PKP examples went to industry, where some survived until late 1980s. At least one (7438/1967), used by ZTKiGK Zabrze (later PTK Holding, now part of DB Schenker Rail Polska), was fitted with Henschel diesel engine.

Two examples have survived until today. SM15-17 (Fablok 7060/1965, withdrawn in January 1977) is displayed at the Railway Museum in Warsaw; this machine logged only about 260 000 km. SM15-22 (Fablok 7065/1965), withdrawn from PKP after only five years’ service and transferred to a track maintenance establishment, is plinthed in Tarnowskie Góry. In the former USSR, TGM3s are still used by RZhD (Russia – number unknown), KTZ (Kazakhstan – three machines) and LDZ (Latvia – two, of which one was withdrawn in 2008); Ukrainian railways UZ withdrew last locomotives of this type in 2007. These data have been taken from and refer to late 2008. Some of them were, or still are used with light passenger trains, so they have perhaps been fitted with some car heating devices, but of this I have no information.

Failure of the SM15 sealed the fate of hydraulic transmission in Polish diesel locomotives. The above-mentioned indigenous type 6D (PKP class SM42) with electric transmission, designed and built also by Fablok, entered production in 1965, to be built in over 2000 examples. This machine was slightly heavier and more powerful than the SM15, but had higher tractive effort (22 800 kN versus 19 600 kN of the Soviet machine) and, first of all, was much more reliable. It still remains the principal medium-power switcher in Poland. Apart from a small batch of two-axle 410D locomotives, built by Zastal in the 1970s for industry, no more efforts to build a diesel locomotive with hydraulic transmission have been undertaken by any Polish railway stock manufacturer.



Main technical data







Years of manufacture


1959 – 1977 (?)


Total built / used in Poland


35961) / 272) + 303)


Axle arrangement




Transmission type




Design maximum speed


55 ¸ 624)


Prime mover type


M751 or M7535)


Engine rating


551 / 750


Bore x stroke

mm x mm

 180 x 200


Number of cylinders




Number of electric engines




Rated output of electric engines




Main reduction gear ratio




Diameter of drivers




Total weight


68 000 – 72 0006)


Axle load


 16.7 – 17.76)


Axle base


 8 100


Overall length


12 600


Maximum width


3 150


Train heating




Brake type




1)      In the USSR and Poland.

2)      For PKP.

3)      For industrial operators – Ls750H and Ls750Hu.

4)      Depending on variant – refers to line operation.

5)      Six examples had M773 engines; four Polish examples had V12 CD19 engines, rated at 800 hp.

6)       Depending on variant.

7)      Original Soviet TGM3 was fitted with the Matrosov brake.


References and acknowledgments


-       Monographic article by Paweł Terczyński and Krzysztof Zintel SK vol. 2/2009 and 3/2009;

-       LOZD vol. 2, AL;


-       Ariel Ciechański (private communication).