PKP class SU45

SU45 (prototype 301D, current type 301Db) is a Polish class of standard gauge mainline mixed traffic diesel locomotives converted for operating local, express 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.

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 SGP 2020.01 was tested by PKP, the tests were successful, but it was not ordered by PKP.^[1] 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.^[1]

In 1965 H. Cegielski – Poznań, despite having no experience with heavy diesel locomotives, came in to develop a locomotive intended for mixed traffic operations.^[1] 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.^[1] 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.^[1]

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.^[2]

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.

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.^[3].

The locomotives were sent to be rebuilt at ZNTK Poznań in 1988, they were equipped with 3 kV DC Dolmet 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,^[3] the remainder that didn't get converted were still in service until the end of the 20th century.

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).^[4] Due to the large amount of power consumed from the engine by the heating system in winter during long uphill climbs, the locomotive doesn't have enough power to maintain the scheduled speed and to heat up the train.^[5]

The locomotive top speed is set to 120 km/h (75 mph), it was set to that speed because most of the non electrified railways had that maximum speed limit. Some older locomotives had smooth bodyframe, and newer locomotives had grooved bodyframe. The locomotive has standard headlights designed in the 1960s (no locomotive used ZEZ headlights). The multiple unit control sockets are mounted on both end of the locomotive to obtain more power for hauling freight trains, in some cases the freight train is heavy enough that it requires two locomotives. Acceleration typically changes based on what type of train it is pulling, an SU45 locomotive without a train accelerates quickly to top speed, with a local train it can quickly reach the same top speed but with an additional weight the acceleration is slower, with an express train it can quickly reach 60 to 70 km/h at first but the acceleration slows down once it reaches above 70 or 80 km/h, which means it would take a long time to reach the top speed with an express train (is can possibly reach between 100 and 120 km/h, EP07 can reach 120 km/h quickly, even with 14 passenger wagons), with a freight train the acceleration is way slower than both passenger trains, reaching possibly 40 to 60 km/h. SU45 locomotives tend to have electrical installaton malfunctions causing a fire, and sometimes technical malfunctions could happen, resulting in a locomotive withdrawal.

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.^[6]

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.^[6]

They also pulled express trains around Poland on long distances between the cities on non electrified routes, although the southern part of Poland wasn't mostly distributed by SU45 locomotives some of them operated there with express trains such as "Śnieżka" or "Wetlina", in some cases they didn't 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 aswell), 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.^[1]

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 weren't electrified, and the SU45 freight traffic was common here.^[6]

In 2001 all of the existing the locomotives came in part of PKP Cargo after the PKP restructurisation, in which switching to freight traffic didn't 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 Przewozy Regionalne, 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^[6]. As of 2009, PKP had 120 locomotives (50 from PKP Cargo, 51 from Prewozy Regionalne and 19 from PKP Intercity).^[1]

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 remining locomotives were assigned to pull special trains on chosen railways such as SU45-079, 089, 115, 164.^[6]

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.^[1] 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,^[7] 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,^[8] 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.^[9] Meanwhie two locomotives (079 and 089) were sold to KSK Wrocław for intented 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.^[10]

SU45-165 didn't 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.^[11] 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.^[12] As of 2026 only 3 of the locomotives are in service and 1 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.

Some SU45 locomotives not long after conversion were withdrawn from service due to the repair costs, engine failures, high fuel consumption and railway electrifications, their first withdrawal started in late 1998 and scrapping of locomotives occurred between 1999 and 2006, numbering 34 of total locomotives.^[6].

The next major SU45 withdrawal occurred between 2009 and 2011 due to more technical problems from the locomotive series and the introduction of the new railbuses built by Newag and Pesa in which were cheaper to maintain, had lower fuel consumption and had more seats, one of the locomotive's operations were taken by the new fleet, meaning railbuses replaced SU45 locomotives, the scrapping occurred between 2009 and 2013 at Lębork, Czeremcha, Gdynia, Lublin, Leszno, Szczecin, Bydgoszcz, Warsaw and other locations, scrapping almost 100 locomotives.^[6]

Next withdrawal occurred between 2014 and 2018 due to the introduction of new locomotives such as SM42 Rebuilds (18D, 6Dl) and SU160 for PKP Intercity; modernised ST44 and SM48 (ST48) locomotives for PKP Cargo; the leasing of Czechslovakian 754 locomotives; and more technical problems. A total of nine locomotives were scrapped in Września, Bydgoszcz and Lublin.^[6]

Even though not all locomotives were scrapped after the withdrawals, some of them were left abandoned, mostly between 2009 and 2016; one of the locomotives was put up for sale via electronic bidding. The last locomotive scrappings occurred between 2020 and 2025 when the abandoned locomotives were bought by metals recycling companies including Olmet and Segromet; most of the abandoned locomotives were owned by Przewozy Regionalne and PKP Cargo.^[6] Karpiel bought nine locomotives (073, 100, 118, 152, 175, 183, 192, 195 and 214) for a refurbishment, but only one was completed (192), the others were in poor condition an seven were scrapped at Brzesko Terminal, leaving only one locomotive (100) remaining there.^[13] A total of 25 locomotives were scrapped in the years 2020–25.

Five locomotives are preserved in three locations, Chojnice, Małaszewice and Wrocław. These include in display, SU45-052, SU45-089, SU45-213 and SU45-228 and the operational SU45-079 as the last locomotive to ever retire from regular service.

This locomotive pulled local trains around Lower Silesia and Opole Voivodeship until it's retirement in 2008, it stayed retired in Kamieniec Ząbkowicki then moved to Wrocław Brochów depot owned by PKP Cargo in Wrocław. After being placed under the depot for a long time it was withdrawn in 2025 and moved to a depot owned by PKP Intercity and KSK Wrocław pulled by SP42-001 locomotive, in which was listed as exhibit part of KSK Wrocław and was preserved in the same year along with other locomotives.^[14]

After its retirement of pulling regional trains around Greater Poland and outside its borders in late 2016, it was displaced in Krzyż along with a Bmnopux wagon at the railway depot. It was withdrawn in 2018 and was bought by ALS S.C. Stary Sącz for KSK Wrocław, which was moved to Ostrów Wielkopolski for a renovation to become a preserved example in working order, after it was sold it obtained a power generator from SU45-241. Its renovation was completed in 2021 but didn't obtain a certificate of working order, It participated in Nysa locomotive parade but in inoperable state the same year. SU45-079 obtained a certificate in 2022 and started operating charter trains as a preserved example, it also participated in another locomotive parade in Nysa and pulled a special train to a test track center near Żmigród, the locomotive participated in multiple railway exhibitions including on the occasion of 80 years of Pafawag. SU45-079 remains as a preserved example in working order today.^[12]

After it's retirement of pulling regional trains around Greater Poland and outside its borders in 2016, it was displaced in Krzyż along with other locomotives including SU45-079 (in which its engine was moved to this locomotive). It was bought by ALS S.C. Stary Sącz for possible renovation, SU45-089 was moved to Ostrów Wielkopolski but didn't get any renovations, it was later moved to Wrocław (especially KSK Wrocław) and it remained as a retired exhibit along other locomotives. The locomotive still awaits for renovation at its disposition as it remains untouched today.^[10]

This locomotive operated intercity trains and freight trains around Poland under PKP Cargo's ownership. In January 2015 during the departure from the Rzeszów Główny railway station with a "San" TLK train numbered 35108 from Przemyśl to Bydgoszcz, the locomotive malfunctioned, in which SU46-031 had to come over from Stalowa Wola to take its train, it remained out of order after it malfunctioned. In 2016 along with other locomotives of its series initially getting retired, SU45-213 was also retired from service and was intended to be preserved for museum purposes under protection. The locomotive was then moved to Warszawa Odolany Depot in Warsaw in 2017 as it remains as an exhibit part of PKP Cargo, due to the depot's closure in January 2025 SU45-213 along with other locomotives were moved to Małaszewice near Terespol. SU45-213 remains as PKP Cargo's exhibit today, in which it's service came to an end after a malfunction.^[15]

Another locomotive with a similar story to SU45-213. In February 2014 while pulling the "San" TLK train, it malfunctioned near Kraśnik in which SM42-1052 was sent to pull its train (it was 270 minutes late). The locomotive was then retired after a malfunction, although in 2016 all of the remaining locomotives of its series came to reitre, SU45-228 was intended to be preserved for museum purposes under protection. Locomotive was bought back from PKP Cargo by SMK Chojnice In 2023 and was moved from Nowy Sącz to Chojnice, it was sent to be restored to become a preserved example in working order for operating Charer trains (same as SU45-079). As of today the locomotive remains still in renovation at Chojnice, it might be restored by 2028 or earlier somehow.^[16]

SU45 locomotives after conversion had 1990s PKP livery which is green and yellow fronts, the 1990s livery sometimes had variants; some locomotive's top side body and side frame would have dark green or light green painting. Every locomotive used this type of livery, nearly 200 of them used it, expect the ones with unique liveries such as SU45-013 with yellow thin stripes on it^[17], some locomotives had yellow thin stripes in it, which was only used by 2 locomotives (013 and 098), other locomotives (or just one) had green and half painted yellow fronts livery used by SU45-154, which later obtained a more unique livery somewhere in the late 90s, and it was green with yellow and orange fronts and front sides, the livery was very unique among railway enthusiasts, but it was only used for a short period of time, converting it back to standard livery in the start of 21st century, SU45-141 had its green with yellow triangle fronts livery, used for 10 years from 1992 to 2002, also unique. The 1990s livery was used from the beginning of SP45 conversion all the way to SU45 retirement between the lats 2000s and the early 2010s. However, 2 locomotives in green livery were repainted to historical 1990s painting, SU45-245 owned by PKP Cargo was repainted to old 90s livery in 2008, it only used it for 3 years upon its retirement in November 2011^[18], the next example is SU45-228 where it was bought by SMK Chojnice for renovation, it was repainted to historical painting from the 90s somehwere in 2024 or 2025,^[16] after it's completed renovation railway enthusiasts will refer it as "Rarytas".

The 2000's PKP green livery started its use in 2002 when some of the locomotives applied it, the remainder of them remained in the old 1990s livery. This livery had more variants, the green painting could be brighter or darker, the roof could be green or grey and the MU sockets could be black. 98 in total used it, and was used from 2002 all the way to the final locomotive retirement in 2016 (14 years of use).^[19] However in 2007, one locomotive (SU45-173) in its remained old livery, obtained the fresh repaint with the frame being painted in red, among railway enthusiasts it was unique also, its livery was used until its retirement somewhere in 2011. SU45-079 owned by KSK Wrocław obtained its historical 2000s livery along with additional decorations in 2021, now its in service with its livery.

Przewozy Regionalne applied its light grey and red livery to only 3 locomotives (018, 070 and 079) in 2009, this livery was used for 2 years by SU45-018 and 070 until its retirement in 2011. SU45-079 managed to still be in service along with its regional livery until 2016 where it retired, but the livery still remained for more 3 years before it was repainted to classic 2000s painting. The Przewozy Regionalne livery was used for 7 years operationally, and used for 10 years technically.

Unikol Railway Workshop applied its blue and yellow fronts livery only for a single locomotive (SU45-141) in 2013, same locomotive that used yellow triangle fronts). It is still used by Unikol today, the livery matches with M62-1891 having the same color schemes.

SKPL Cargo along with other locomotives applied to SU45-115 Blue with red and white diagonal buffer stripes livery in 2017, which it matches every locomotive owned by SKPL Cargo. Although SU45-115 still applies it, the paint slowly loses its durability.

Karpiel applied to SU45-194 (192) blue and light grey BTK livery in 2017. The livery matches with SM42-2097 somehow, as it has some large white letters on both sides. According to some enthusiasts, SU45-194 has an unique livery at some point. The livery is stil being used today.

• On 19 February 1992, SU45-005 caught on fire in Czernikowo, in which the locomotive was sent to be repaired.^[20]

• In 1998, SU45-097 collided with a truck on a railway crossing in Luboń, the driver of the locomotive possibly died. After the accident the cabin from the SU45-047 had to be installed due to the damage.^[21]
• On 8 May 1999, SU45-157 with an express train numbered 26220 from Hrubieszów to Wrocław derailed on the Zwierzyniec - Biłgoraj line in Hedwiżyn, 3 people were injured. The cause of derailment was the damage of a railway switch.^[22]
• On 25 May 2000, SU45-175 colloded with a truck hauling sand on a railway crossing in Granowo Nowotomyskie. Both drivers died, cab from the SU45-040 had to be installed due to the damage.^[23]
• On 22 August 2004, SU45-057 caught on fire due to electrical malfunction near the Chojnice station while operating a local train from Tczew to Chojnice. Passengers quickly escaped the train, once the firefighters arrived the locomotive was uncoupled from the train, 9 firefighters extinguished the locomotive, no one was hurt in the incident.^[24]
• On 11 December 2007, SU45-018 with an intercity train from Suwałki to Łódź collided with a car on the railway crossing around Dąbrowa.^[25]
• On 13 October 2010, SU45-214 with an intercity train from Białystok to Szczecin around Ełk, locomotive caught on fire due to electrical malfunction.^[26]
• On 22 April 2011, SU45-210 with a freight train from Gdynia to Bydgoszcz in Somonino collided with a Mercedes car, no one was hurt.^[27]
• On 21 July 2012, SU45-220 with a "Hetman" TLK train in Tarnowska Wola at around 8:00 am, hit a broken tree hanging above the railway. Driver of the locomotive was injured.^[28]
• On 13 March 2015, SU45-079, in Trzcianka at around 14:10 on the Kopernika street railway crossing, locomotive collided with a Renault car. Leaving only 1 driver dead and 1 passenger injured.^[12]
• On 27 April 2018, 301Db-143 collided with a car in Cychry, leaving only one person injured.^[29]
• On 13 December 2018, SU45-194 (192) heading to the station from the terminal derailed on two axles on the category b railway crossing in Brzesko.^[9]

New locomotives were too expensive for PKP Cargo so it decided to modernise its own locomotives, including SU45, so the SU45 locomotive modernization announcement appeared in the late 2007, as well as the start of modernizing. The SU45 locomotive reconstruction was made by Pesa Bydgoszcz on the basis of technical documentation prepared by the "Tabor" Railway Vechicle Institute, in which the agreement concluded between PKP Cargo and Pesa assuming the modernization of 20 locomotives for the Polish freight company.^[30]

The modernization started in 2007, in which the first locomotive rebuilt was SU45-112 being modernized in 2009 and reclassifed to ST45-01, next it was tested in May 29th on the Bydgoszcz - Laskowice Pomorskie route and back. ST45 locomotives were rebuilt between 2009 and 2012, rebuilding only 19 locomotives (3 locomotives supposed to be rebuilt but due to its significant wear they were later scrapped instead).^[31]

The locomotives had MTU 4000 diesel engines with a rated power of 1500 kW (2040 hp) that meet the EURO 3 emission standards and had less weight, the elements of heating the composition were removed, air conditioning was installed, the electrical installation has been modified, Halogen and LED headlights were installed, multiple control sockets were removed (which have been replaced by one of transmitting information between on board computers), and LS-90 cabin signalling system was equipped.^[32]

The locomotives were assigned to Kuyavian plant of PKP Cargo and were distributed around Kuyavian-Pomeranian Voivodeship, mostly on the Grudziądz - Terespol Pomorski route and around Toruń, hauling most likely gravel. ST45-04 was assigned to Czechowice-Dziedzice depot part of Silesian-Dąbrowa plant of PKP Cargo in 2010, in which mostly hauled newly built road vechicles from Fiat car factory in Tychy, more of the locomotives were brought to Czechowice-Dziedzice depot somehow in which they operated in different orders. In 2011 one of the locomotives obtained admission to traffic in the areas of Czech Republic (they also obtained admission to traffic in Slovakia).^[33]

Although the locomotives weren't powerful enough compared with other modernized locomotives, they were too weak for operation. Some locomotives started its retirement in 2017, next in 2019 and most of the locomotives were retired in 2020. They were all displaced in Bydgoszcz, Skarżysko-Kamienna, Szczecinek, Jaworzno, Lublin and Czechowice-Dziedzice, and in 2024 they were put up for sale for electronic bidding.^[34]

These locos used to be called by the following names:

• Fiat - because of the diesel engine licensed by Fiat
• Suka (eng. bitch) - from the two first letters of the code name (the SU46 series locomotive was more often called a "bitch" due to the greater engine power and the greater number of power shunting stages. SU45 is a locomotive with the same engine, but less power, which is why most drivers and railway enthusiasts pay attention to the gentler character of the SU45, which is why "Fiat" or "Fiacik" fits better)

• Polish locomotives designation
• PKP class SP45

• Modern Locos Gallery
• Rail Service
• Mikoleje
• Chabówka Rail Museum
• Locomotives.com
• SU45 locomotive startup
• The last Polish SU45 Diesel locomotives