Russian TGM40-0465, photographed at the Kiziterinka station near Rostov on Don, March 25, 2006...




...and another picture of this machine, taken on the same occasion. Both photos by Vadim Anokhin (thanks for permission!).




TGM40-0590, STEICO, Czarnków, probably late 2006. Photo from (used by permission). This locomotive is probably still in use.




This TGM40-0507 is operated by the ZNTK Bydgoszcz railway stock repair works and was photographed there on May 14, 1997. Photo by Filip Sieradzki (from my collection). This locomotive has already been withdrawn.



TGM40-0586, operated by MZEC Świdnica district heating company; location unknown, August 12, 1998. Photo by A. Palla (from my collection).



In July 2007 TGM40-0586 was sold to SKPL. This locomotive, sporting a new livery and slightly modified service number (zero omitted) was photographed in Pleszew on October 19, 2018.



Another picture taken on this occasion: this locomotive is probably TGM40-718, also operated by SKPL.



Russian TGM40-0386, operated by an unidentified industrial establishment, photographed in Cherkizovo on June 25, 2003. Photo by Artem Svetlov (source:





In late 1970s, Kambarka Machine Building Works in the USSR conceived an idea to develop a family of light diesel locomotives for 750 mm, 900 mm, 1067 mm and 1524 mm tracks. All these variants were to be derived from the TU7 narrow-gauge locomotive, in production since 1971 (mainly for forestry and paper industry, also for export), fitted with a V-12 400 hp diesel engine and hydraulic transmission. While narrow-gauge variants proved successful, standard-gauge one, which appeared in 1978, did not. It was soon found that plain replacement of trucks would not work and standard-gauge TU7 had to be substantially modified. Diameter of wheels was increased from 600 to 950 mm, trucks were enlarged and frame and body were also substantially modified. Overall length increased from 9400 to 11 290 mm and weight in working order from 24 to 34 tonnes (for better adhesion, the machine could be ballasted up to 40 tonnes.) However, with the Bo’Bo’ layout, axle load remained on a moderate level.

Two prototypes, designated TU7M, were built in 1981 and were later re-designated TGM40 (T stood for diesel locomotive, G for hydraulic transmission and M for switcher). Production started in 1982 and was terminated in 1996, although several additional examples were delivered between 1999 and 2002. This locomotive was built only for industrial operators and export and saw no service with Soviet railways SŽD or with railways of post-Soviet republics. TGM40 is fitted with high-speed 1D12-400B diesel engine, the same as in TU7 (rated power at 1600 rpm) and two-stage hydraulic torque converter; first stage is employed at startup and second during normal run. Transmission gear is a slightly modified variant of that used in TU7. This locomotive can develop the tractive effort of 9.7 tonnes at 6.4 km/h or, with ballast, 11.8 tonnes at 4 km/h. Maximum speed is 40 km/h. TGM40-01, introduced in 1988, featured several minor modifications, while TGM40-02, of which six examples were built between 1989 and 1992, was fitted with a de-rated 300 hp diesel engine. There is also a specialized version with snow-plough (which adds seven tonnes to the weight), designated TGM40S, of which 240 examples were built. According to, total output of all versions was 1235 examples. As far as power and tractive effort are concerned, TGM40 is roughly equivalent to Polish SM25, which was never accepted for production. Polish locomotive, with three axles coupled by connecting rods, was slightly more powerful, but axle load was 12.4 tonnes.

Despite rather discouraging experience with hydraulic transmission, several locomotives of this type were imported to Poland, but all went to industry and were never used by PKP. One source ( gives that, in all, twenty examples were purchased, most of them in late 1980s. Another source, a very reliable one ( lists eighteen examples; this is confirmed by Four of them, previously used by the Zabrze foundry (two), PESA (one) and PZZ Warszawa Białołęka food industry establishment (one), have already been withdrawn, despite relatively young age and low mileage. No Polish designation was assigned to these locomotives and they are identified by TGM40 plus three- or four-digit number, probably corresponding to serial. They were scattered among various industrial establishments and their service attracted little attention: TGM40-0716, built in 1990 and delivered to a food industry plant in Lublin, clocked just 11 650 kilometers during twenty years! I personally recall TGM40-0509 in orange livery, used by an electrical industry plant in Warsaw; I saw it from time to time on the factory siding, but never had my camera with me! Later the plant closed down and the locomotive was sold in 2008 to SKPL (Association for Local Railway Traffic). Currently it is operated on a local line in Pleszew. SKPL has the largest ‘fleet’ of TGM40s, numbering four examples in all, including the above-mentioned TGM40-0716, purchased from a scrap disposal company (!).


Main technical data







Years of manufacture


1981 – ?


Total built / used in Poland


1235 / 18


Axle arrangement




Transmission type




Design maximum speed




Prime mover type




Engine rating


294 / 400


Bore x stroke

mm x mm

150 x180 / 186.71)


Number of cylinders




Number of electric engines




Rated output of electric engines




Main reduction gear ratio




Diameter of drivers




Total weight


34 0002)


Axle load




Axle base


6 875


Overall length


11 290


Maximum width


2 950


Train heating




Brake type




1)     Master / articulated connecting rods.

2)     40 000 kg with ballast.

3)     10.0 tonnes with ballast.


References and acknowledgments


-       Locomotives and Railcars of Soviet Railways 1976-1985 by V.A. Rakov (via Vadim Anokhin);





-       SK, various issues;

-       MAL, AV vol. 2.