797.8

The ancestors: 701 069-7…

…and 701 776-7, both photographed at the Railway Museum, Lužna u Rakovnika, Czech Republic, on June 14, 2008.

797.823-2 displayed at the TRAKO 2011 Fair in Gdańsk; October 14, 2011.

Side drawing of the 797.8; source: CZ Loko folder.

Slightly derelict class 700, number unknown; photo taken in Tanvald, Czech Republic, on April 2, 2011.

797 819-0 of Metro Warszawskie (Warsaw Underground). Photo taken on September 20, 2008, at the Kabaty depot by Janusz Jakubowski (source: www.commons.wikimedia.org).

In 1955 ČKD (Českomoravská Kolben-Danĕk), well-known Czechoslovakian locomotive manufacturer, built the prototype of BN 150 light switcher, intended mainly for industry and service duties. It was fitted with Mylius mechanical transmission and power was provided by Tatra 111A V-12 165 hp air-cooled diesel. Further two prototypes featured hydraulic transmission. Designated T211.0 and T211.1, respectively, these locomotives underwent service tests and the former was finally accepted for large-scale production. Until 1962, 824 examples were built in both standard-gauge and narrow-gauge (760 mm, 900 mm, 1000 mm) variants, of which 197 went for export, including 1524 mm version for the USSR and 1676 mm version for India. Hydraulic-transmission T211.1 was built in only nine examples for the 900 mm track, between 1960 and 1961. Many T211.0s were later re-engined with Tatra T930.51 (class T211.1 – designation used for the second time) or Tatra T3-928.32 (class T211.2) air-cooled diesels, both rated at 200 hp.

Modified variants of this locomotive included class T212.0 (mechanical transmission, T930.51 engine) and T212.1 (hydraulic transmission, T930.54 engine rated at 230 hp). Both went into production, the former at Turčianské Strojárne of Martin in Slovakia, with total outputs numbering 382 examples (1966 – 1971) and 224 examples (1969 – 1979), respectively. This gives 1441 examples in all. Individual batches different externally mainly in engine cowling shape and cooling air inlet. Later, with the introduction of new designation system, they were re-classed 700 (former T211.0), 701 (T211.1), 701.3 (T211.2), 702 (T212.0) and 703 (T212.1). Their common nickname is ‘Prasátko’ (Piglet).

These light and versatile locomotives found widespread use and were praised for simplicity and robustness. Several modernization packages were introduced starting from mid-1990s, including new prime movers (LIAZ, MTU or Caterpillar), new body and numerous minor modification. Perhaps the most radical one is class 797, which features AC/DC electric transmission. Conversions were made at railway depots and JLS (Jihlavska Lokomotivní Společnost, in 2000 re-named ČMKS Jihlava, now CZ Loko). The most numerous sub-variant of this class is 797.8, initially ordered by Prague underground (seventeen examples supplied between 1996 and 2002). It featured 330 hp LIAZ diesel engine which drove the alternator and traction engine, power from the latter being transmitted to gearbox and then by Cardan shafts to individual axle gears. Externally this locomotive does not resemble its predecessor at all: in fact, little more than the original frame has been retained.

In 2008, Warsaw underground ordered one locomotive of this type, with 340 hp Caterpillar C9 diesel. Numbered 797.819-0, it was delivered to the Kabaty depot. Second example, 797.823-2, this time for the Adamów lignite mine, followed in 2011. Prior to delivery, and still with original Czech service number, it was displayed at the TRAKO Fair in Gdańsk by CZ Loko. This locomotive (rebuilt from the 703.573-6) is to replace an elderly Ls60, built in 1963. Other foreign orders came from Hungary (Budapest underground, two) and Bosnia and Herzegovina (Tuzla power plant, also two).

Main technical data

No.	Parameter	Unit	Value
1.	Years of manufacture	-	1996 – ^1)
2.	Total built / used in Poland	-	23^2) / 2^2)
3.	Axle arrangement	-	B
4.	Transmission type	-	electric
5.	Design maximum speed	km/h	40
6.	Prime mover type	-	Caterpillar C9^3)
7.	Engine rating	kW/hp	250 / 340
8.	Bore x stroke	mm x mm	112 x 149
9.	Number of cylinders	-	6
10.	Number of electric engines	-	1 x TE015^3)
11.	Rated output of electric engines	kW	315
12.	Main reduction gear ratio	-	68 : 23 / 57 : 17^4)
13.	Diameter of drivers	mm	1000
14.	Total weight	kg	25 000
15.	Axle load	T	12.5
16.	Axle base	mm	2 800
17.	Overall length	mm	7 240
18.	Maximum width	mm	2 750
19.	Train heating	-	-
20.	Brake type	-	DAKO-GP

1) Reconstruction.

2) Until late 2011.

3) 330 hp LIAZ M 1.2C M640SE diesel and TE005 205 kW traction engine in earlier examples.

4) Main / axle gear.

References and acknowledgments

- AV vol. 2, MAL;

- http://spz.logout.cz.

- Chris West (private communication).