SU45 (prototype 301D, current type 301Db) is a Polish class of main mixed traffic diesel electric locomotives converted from SP45 for operating passenger and freight trains in Poland. Built from 1970 to 1976 by H. Cegielski in Poznań as the passenger version classified SP45, they were later converted to mixed traffic by ZNTK Poznań.
SU45 locomotives were one of the most popular locomotive series throughout Poland associated with Polish national railway.
Origins Before the prototype
Steam locomotive orders were declining in 1957 for the Polish railway dieselisation, in which development of new diesel locomotives were necessary, but not for the mainline locomotives. In 1961 the Austrian diesel hydraulic locomotive prototype ÖBB Class 2020.01 was tested by PKP, the tests were successful, but it was not ordered by PKP. It was then decided to develop a new mainline locomotive to run on non-electrified railway lines, which was then started by Central Construction Bureau of Railway Stock Industry (CBKPTK) in 1963.
Prototype In 1965 H. Cegielski – Poznań, despite having no experience with heavy diesel locomotives, came in to develop a locomotive intended for mixed traffic operations. The 12C22W prime mover was designed by Central Design Bureau for Internal Combustion Engines (CBKSS) intended to develop 1700 HP at 1100 rpm, but as built by Cegielski it was reduced to 1520 HP at 1020 rpm. The locomotive itself initially designated SU44 was designed by CBKPTK in Poznań, but due to the delays of the development problems the SU45 locomotive design was made.
The first prototype was built in 1967 by Cegielski, it was fitted with a Vapor steam boiler intended for train heating, streamlined headlights, electric components made by Dolmel, bogies made by Fablok and the engine made by the same company. The tests began in August and operational testing began in October on the Poznań - Gdynia route.
The results of the tests were unsatisfactory, some problems occurred with the design, especially the engine; it was proven to be unreliable for the operation. The design was not purchased by PKP, the prototype was then scrapped in the mid-1970s and later the decision was taken to construct a second prototype with an engine under a license from Fiat; this was intended only for passenger service and classified SP45.
SP45 conversion Due to the multiple problems with the Vapor steam boiler, such as the spares needed to be imported from the United States (which was deemed to be too expensive), the increase of electrically heated passenger wagons, the troubles with switching the trains into different traction, and having to choose between achieving scheduled speeds or to heat up the train (especially on the inclines during winter), it was decided to modify SP45 locomotives to electric heating.
The locomotives were sent to be rebuilt at ZNTK Poznań in 1988, they were equipped with 3 kV DC Dolmel LCPb-400 electric train heating and its multiple control sockets were placed on both ends for freight traffic, meaning they were converted for mixed traffic service. Although due to the next railway electrification, locomotives were moved to low category railway lines. The first locomotive rebuilt was SP45-074 and the last was SP45-061, the conversion took 9 years from 1988 to 1997 converting only 191 locomotives, the remainder that did not get converted were still in service until the end of the 20th century.
Design The SU45 is a diesel electric mixed traffic mainline locomotive with Co'Co' Six-axle bogies, 2112SSF internal combustion engine powered by diesel, electric 3 kV train heating and multiple control system. The welded mainstay with a locomotive body is a self-supporting structure, both locomotive cabs are placed on both directed compartments allowing a better driver's view. In the middle of the locomotive, a 12-cylinder, four-stroke, diesel internal combustion engine 2112SSF built by Fiat under license is located, along with a top-up with the GP-846B1 main generator built by Dolmel in Wrocław under license from Alstom, in which is also used as a starter. On both compartments between the engine and the driver's cab, a cooling unit and a 3 kV DC electric train heating system LCPb-400 are located. Six LSa-430 traction motors are mounted on each axle of the locomotive's bogies, the engines are suspended by the tram system ("by the nose"). Between the locomotive's bogies, there is a battery, water tank and most importantly a 3500 Liter fuel tank, the transfer of the pulling force and the braking system from the bogies to the body is carried out by an angle ever. Its engine oil consumption is 36L per hour, and its diesel fuel consumption is 223 g/kWh (164 g/hph), which at rated power under normal conditions gives 279 kg/h (1700 hp). Due to the large amount of power consumed from the engine by the heating system in winter during long uphill climbs, the locomotive does not have enough power to maintain the scheduled speed and to heat up the train.
Service
SU45 locomotives were assigned to operate local trains, express trains and sometimes freight trains on non electrified railway lines around Poland. They were mostly used in the northwestern, northern and eastern macroregions of Poland including Greater Poland Voivodeship, Lubusz Voivodeship, West Pomeranian, Kuyavian-Pomeranian and Pomeranian Voivodeships, Warmian-Masurian Voivodeship, Podlaskie Voivodeship and Lublin Voivodeship, these were the common SU45 locomotive distribution areas.
The common type of traffic used by these locomotives was passenger traffic, most likely local and express trains. The locomotives pulled local trains on distributed areas around voivodeships and between its borders linking the towns from different regions or in the same region, also outside Poland's western borders where they pulled local trains to Germany, including Frankfurt (Oder), some of the trains they pulled consisted of BHP wagons, Ryflak wagons and/or 120A type wagons. Additionally they pulled interregional trains including the Wrocław - Dresden train.
They also pulled express trains around Poland on long distances between the cities on non electrified routes, although the southern part of Poland was not mostly distributed by SU45 locomotives some of them operated there with express trains such as "Śnieżka" or "Wetlina", in some cases they did not pull the express trains from the start all the way to its final destination, the trains might be pulled by electric locomotives in which they stop at some stations with the maximum overhead catenary range in order for them to couple up with the train and continue the scheduled route along the non electrified railway lines (it was common on the Hel Peninsula, SU45 locomotives operated there as well), up north between the Polish and the Russian border they operated express trains from Gdynia to Kaliningrad, until 2004 when they were replaced by M62 locomotives going all the way to Kaliningrad in which they only stopped at the border station of Mamonovo, the rest of the route being operated by a Russian locomotive.
They sometimes pulled freight along non electrified branchlines on short distances around distributed areas of its locomotive series, they would carry wood, coal, goods or even freight outside the borders including Russia, or sometimes carry mixed freight.
SU45 locomotives were allocated at the same railway depots before they were converted to mixed traffic including some junction station depots located in small settlements, they were later assigned to larger depots with more stationing areas due to the fleet change or sometimes the depot closure, in fact Łódż had only 2 locomotives because most of its railways around were mostly electrified, and Białystok had 35 locomotives in which the railways around were not electrified, and the SU45 freight traffic was common here.
In 2001 all of the existing the locomotives came in part of PKP Cargo after the PKP restructurisation, in which switching to freight traffic did not affect, also after the restructurisation they pulled express trains under the new types such as Intercity or TLK (Twoje Linie Kolejowe). They all were part of PKP Cargo ownership until 2008 when some of the locomotives came in part of PKP's railway companies; PKP Intercity and Polregio, the other numbered from 198 to 265 remained in PKP Cargo and yet they hauled freight trains more frequently along with Passenger traffic sometimes, its railway depots also came in part of PKP Cargo. As of 2009, PKP had 120 locomotives (50 from PKP Cargo, 51 from Prewozy Regionalne and 19 from PKP Intercity).
Locomotives operating regional trains were starting to get replaced by Railbuses in which they were much cheaper to maintain, most of the locomotives stopped operating in Pomeranian Voivodeship, West Pomeranian Voivodeship, Warmian-Masurian Voivodeship, Podlaskie Voivodeship and Lublin Voivodeship, the remaining locomotives in part of PKP Cargo and PKP Intercity were still in service. while some of the locomotives were getting retired from service not all were replaced in Greater Poland voivodeship as they pulled regional trains around this region, some of the remaining locomotives were assigned to pull special trains on chosen railways such as SU45-079, 089, 115, 164.
Two locomotives (141 and 165) were bought by Unikol Railway Workshop in Kostrzyn in 2011, SU45-141 was refurbished and reclassified to 301Db-141 in 2013 (later changing its fleet number to 143), it was assigned to gather empty wagons mostly tanker wagons to the workshop for the inspection and/or repairs and operate shunting duties on railway yards. The remaining locomotives were retired from Intercity service in 2015 and retired from regional service in 2016, 9 retired locomotives were bought by Karpiel for refurbishment most likely, and the last locomotives (079, 089 and 115) were retired from regular passenger service. Later on SU45-115 was bought by SKPL Cargo in which was refurbished and tested on Ostrów Wielkopolski - Kalisz route and back, after the test run it went out of service due to an engine malfunction and was placed next to other SKPL owned fleet in Ostrów Wielkopolski. SU45-192 was bought by Karpiel along with other locomotives, as the refurbishment for these locomotives was intended only one was a successful example (192) in which was refurbished in 2017 (also changing fleet number to 194) and was then assigned to operate only shunting duties on the Brzesko Terminal in Brzesko in 2018 due to the withdrawal of the transport licence by the office of railway transport. Meanwhie two locomotives (079 and 089) were sold to KSK Wrocław for intended preservation for charter service around Lower Silesia and Opole Voivodeship, the refurbishment was intended for both locomotives in which only one locomotive (079) was a successful example, the second (089) is still awaiting for the refurbishment at KSK Wrocław.
Summary
SU45-165 did not get any refurbishments instead some of its parts were removed and was put up for sale on OLX at a price of 42500 PLN in 2025. SU45-194 entered freight service in 2019 assigned to pull mostly container freight trains around Southern Poland and operate charter trains as well. Preserved example SU45-079 entered charter service in 2021 and also took part in locomotive parades in Nysa. As of 2026 only three of the locomotives are in service and one out of service, 301Db-143, SU45-079 and SU45-194 remain in service today while SU45-089 and SU45-115 remain awaiting for repair today.
+Distribution of locomotives, December 1997CodeNameQuantityGYAGdynia8CJEChojnice21LBNLublin20WCWWrocław10BYKBiałystok35TRŃToruń14BOZBydgoszcz11OZNOlsztyn6PZŃPoznań28CWKCzerwieńsk10SZNSzczecin9BODBiałogard16ŁDŹŁódź2Withdrawn (1997)1Total rebuilt:191
Withdrawal and scrapping