SM15

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

TGM3 prototype; source – as above

Cross section of the TGM3; source – as above

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This locomotive, Ls750-7438 from PTKiGK Zabrze (withdrawn), was photographed by Roman Ficek in Zabrze in September 1988 – thanks for permission!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

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 was out of question, so no further examples followed.

Take two came in 1963. In parallel with the design of the 6D medium-power switcher with slow-running a8C22 800 hp diesel engine and electric transmission (which eventually became SM42), two examples of its equivalent with hydraulic torque converters were purchased in the USSR. These were TGM3 machines, 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 TG^V 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 954 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 1932 examples had been built until 1977, bringing the grand total to 3542 examples. This number does not include experimental versions, designated TGM3^M, TGS and TGM3^O, differing mainly in transmission, which never entered production. Machines of this type served with Soviet railways, but most (2360) went to other operators, mainly industrial establishments. It is quite possible that production of this type continued after 1977; LOZD gives their total output as ‘slightly below 4000’, of which about 1200 were accepted by MPS (i.e. state railways).

Two TGM3s were purchased by PKP in 1963 and designated SM15. License agreement followed soon: SM15s were to be built by Fablok in Chrzanów (factory designation Ls750H, later 12D), both for PKP and industry. Diesel engines and hydraulic torque converters were imported from the USSR. SM15 soon earned a bad reputation of a weak and extremely unreliable machine. Failures concerned mainly diesel engines and transmission. Until 1966, when production of this type was terminated, only 25 machines had been built by Fablok for PKP. According to AL, thirty more were supplied to various industrial operators, including modified Ls750Hu with hydrokinetic torque converters. Data supplied by Ariel Ciechański (thanks a lot!) list 28 of them, the highest service number (probably corresponding to serial) being 7564. Of these, collieries and sand railways used twelve; the rest went mainly to chemical and petroleum industry. Several examples were fitted with Polish V12CT19 diesel of similar rating; this engine was successful, but its development was discontinued.

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. Their availability remained very low and withdrawals started surprisingly soon: according to data from www.kolej.pl/~jareks (unfortunately, this link has been dead for some time), seven examples were written off in 1968, just two years after last SM15s were accepted! SM15-03, the first one built by Fablok, was the last to be withdrawn: this took place in 1978, after only 15 years in service. Two examples have survived until today: SM15-17 (Fablok 6763/1965, withdrawn in 1977) is displayed at the Railway Museum in Warsaw and SM15-22 (Fablok 6768/1965, withdrawn after only five years’ service) is plinthed in Tarnowskie Góry. In the former USSR, TGM3s are still used by RZD (Russia – number unknown), UZ (Ukraine – as above), KTZ (Kazakhstan – three machines) and LDZ (Latvia – only two examples); these data have been taken from www.railfaneurope.net. Some of them 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 1800 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. No more efforts to build a diesel locomotive with hydraulic transmission have been undertaken by any Polish railway stock manufacturer.

Main technical data

No.	Parameter	Unit	Value
1.	Years of manufacture	-	1959 – 1977 (?)
2.	Total built / used in Poland	-	3597¹⁾ / 27²⁾ + 30³⁾
3.	Axle arrangement	-	Bo’Bo’
4.	Transmission type	-	hydraulic
5.	Design maximum speed	km/h	55 ¸ 62⁴⁾
6.	Prime mover type	-	M751 or M753⁵⁾
7.	Engine rating	kW/hp	551 / 750
8.	Bore X stroke	mmXmm	180 X 200
9.	Number of cylinders	-	12
10.	Number of electric engines	-	-
11.	Rated output of electric engines	kW	-
12.	Main reduction gear ratio	-	-
13.	Diameter of drivers	mm	1050
14.	Total weight	kg	70 000 – 72 000⁶⁾
15.	Axle load	T	17.0
16.	Axle base	mm	8 100
17.	Overall length	mm	12 600
18.	Maximum width	mm
19.	Train heating	-	-
20.	Brake type	-

1) In the USSR, including TGM3 (1959 – 1967, 954 examples), TGM3A (1961 – 1970, 656 examples) and TGM3B (1966 – 1977, 1932 examples) until 1977 r., and in Poland; LOZD gives slightly below 4000.

2) For PKP

3) For industrial operators – Ls750H and Ls750Hu

4) Depending on variant – refers to line operation.

5) Six examples had M773 engines; several Polish examples had V12CD19 engines,

6) Depending on variant

References and acknowledgments

Technical and historical data can be found in LOZD vol.2. Some information on Polish machines and rosters are available at http://www.kolej.pl/~jareks/wtpkp – this page is maintained by Jarek Stawarz aka Chester. Concise description and statistical data can also be found in AL.