After World War II, the DSB turned to General Motors for a license-built variant of the F-series freight locomotives. Nydquist och Holm (NoHAB) from Trollhättan, Sweden, was found as a European partner for implementation. NoHAB mainly manufactured steam locomotives, but had already started manufacturing diesel engines in the twenties and had the opportunity to manufacture the engines under license in addition to the locomotives.

Since the North American locomotives were almost always used in multiple units, there were locomotives with one or no driver's cab. A second driver's cab was added for use in Europe so that the locomotives, which were usually only used in single operation, did not have to be turned. In addition, the locomotive body had to be adapted to the smaller loading gauge. It borrowed from the GM Class of the Victorian Railways and pulled the roof line far down, which also lowered the side windows and gave the windscreens a special shape.

As with the F series, only four traction motors were used, but six axles had to be used to comply with the axle loads permitted in Europe, which led to the wheel arrangement A1A-A1A. Nevertheless, the axle load was still too high for many branch lines, so they could not be used everywhere. They had been given an additional steam boiler for use in front of passenger trains. The speed increased to 133 km/h also improved the suitability for this area of application.

The first four locomotives were delivered in 1954 and each had engines with a gross output of 1,700 hp. From the second series of 40 locomotives, which were delivered between 1956 and 1958, an improved version of the engine with 1,950 hp was used. 15 more of this version were delivered in 1964 and 1965.

The DSB used them in front of all types of trains. With the disappearance of passenger cars with steam heating, the boilers and water tanks were also removed from some locomotives. Later it was only used in front of lighter freight trains. At the DSB, the locomotives were used in scheduled operation until 1992 and then mostly sold to private operators. Some of these are still in use today and also made their way to Sweden and Germany. In Germany, ten went to Eurotrack in 1999, nine of which later went to Eichholz Verkehr und Logistik and then to Strabag.

After the DSB had already procured licensed American EMD locomotives from NoHAB in Sweden in the 1950s, another series of this type followed from 1967 with the MZ. The locomotive body and the traction motors were produced in Denmark. Like all EMD locomotives of that time, these were diesel-electric locomotives with a two-stroke diesel. With the then current sixteen cylinders of the 645 series with 3,300 hp, the first series of the MZ was already the most powerful diesel locomotive in Europe at the time it went into service. In contrast to the previous MY and MX series, all six axles were powered to transmit all the power to the rails.

The first series, which later became known as the MZ (I), was followed in 1970 by the technically almost identical MZ (II). Both were equipped with steam heating for heating passenger trains. From 1972 the third series followed, which got the twenty-cylinder known from the SD45 with here 3,900 hp. At the same time, the top speed was increased from 143 to 165 km/h. From 1977, the MZ (IV) finally followed, which had electric train heating for the first time. With these four series, a total of 61 pieces were created.

From 1978, the MZ (III) also received electric train heating with an output of up to 480 kW. The steam generators were not removed until 1985. Between 1980 and 1985, the first two series also received electric train heating. This had an output of up to 440 kW and was powered by an additional diesel engine in order not to further strain the engine output, which was lower than that of the later series. Also in the 1980s, a snow plow and radios for route radio were installed after a particularly harsh winter had revealed the weaknesses of the locomotives. After the phasing out, which started in 2000, many engines were sold to Sweden and Australia.

The VR listed the first heavy mainline diesel locomotives, which were built from 1959 to replace steam locomotives, as Hr12. With a six-axle chassis, an output of 1,400 kW and a maximum speed of 120 km/h, heavy goods and passenger trains alike were to be transported.

The engine came from MAN and was manufactured under license by Tampella. It had 16 cylinders with a displacement of 182 liters in total. The axle load was more than 20 tonnes, but this was not a problem for the planned area of work on main routes. Steam heating was available at the time to heat passenger trains. Of the 42 pieces produced, only the last ten were designed for a top speed of 140 km/h, although this was not used in reality and no certification for higher speeds was given.

With the extinction of passenger cars with steam heating, the steam boilers were later removed and the locomotives were only used in front of freight trains. Compared to newer diesel locomotives, it became clear over time that the engine power of the locomotives, now known as Hr12, was relatively low in comparison to the weight. This made them predestined for heavy, slow freight trains in later years. After the large main lines in Finland were electrified, the locomotives could not be used on many of the remaining non-electrified branch lines due to the high axle load. The locomotive, which was the last Dr12 to pull a freight train in December 1990, was preserved for posterity.

To complement the Hr12 (later Dr12), the Finnish State Railways ordered the Hr13 at the beginning of the sixties. The new locomotive had also six axles, but had a lower axle load and were indeed much more powerful. Their technical basis had come from Alsthom in France with an MGO diesel engine from SACM. Only the first two locomotives were assembled by Alsthom, the other 52 were license-built in Finland, including their diesel engines.

Like many French locomotives, they had one traction motor per bogie that was connected to three axles each. The gear ratio could be switched between a top speed of 100 and 140 km/h while stationary. With the new class scheme of 1976, they were renamed to Dr13. The last ones were retired in 2000.

The Sv12 is a diesel-hydraulic road locomotive built by Valmet and Lokomo between 1964 and 1984. It has bogies from the German V160, which can be switched between a top speed of 85 and 125 km/h. A version with an additional steam generator for passenger trains was called Sr12. After the steam generator was removed due to lack of demand, both variants were referred to as Dv12.

Since the installed power of 1,000 kW became too low over time, the locomotives are now mostly used double or triple headed. From 1978, No. 2501 was converted into an electric locomotive with 1,100 kW and tested in this form for four years. Since most of the main lines in Finland are now electrified, retirements began in 2009 and the remaining locomotives are now mainly used on branch lines and in shunting services. The diesel-electric, twin-engine Dr19 is currently being introduced as a successor on non-electrified lines.

In order to be able to replace worn-out steam locomotives on non-electrified routes, the NSB ordered three diesel locomotives from NoHAB, MaK and KHD in 1954. The NoHAB locomotive was built under license from the American EMD F series with two driver's cabs and adapted to the European loading gauge. It largely corresponded to the Danish MY (II) series, but was only designed for 105 km/h instead of 133 km/h. In the meantime, the NSB started the “Vekk med dampen” (“Away with the steam”) program, with which the fleet was to be generally converted to diesel and electric locomotives.

Since the Type 64 from NoHAB was superior to the two competitors, NSB ordered further examples of the series now known as Di 3 for the routes that were not to be electrified. They already had the improved engine of the later series MY (II) with 1,950 hp. In contrast to the MY (II), they received traction motors on all six axles and grilles in front of the windscreens to protect against falling icicles from bridges and tunnels as an adaptation to Norwegian conditions. After 32 Di 3a followed three Di 3b, which were actually intended for the Finnish State Railways and had a gear ratio for 143 km/h in addition to the wheel arrangement A1A-A1A.

Among others, the locomotives replaced the Type 49 “Dovregubben” on the Dovrebane in heavy express service. However, some bridges first had to be rebuilt for the higher axle load of the Di 3, so that steam locomotives were used on main routes until 1970. With increasing electrification of the routes in the southern parts of the country, they were pushed into the northern parts of the country, some of which are not electrified to this day.

At the beginning of the 1980s, the steam boiler was replaced with an auxiliary diesel generator to heat newer passenger cars. They were soon replaced by the Di 4, initially in front of passenger trains. From the 1990s they were replaced in freight traffic by the Di 8 and Class 66, while the last passenger trains were taken over by diesel multiple units. After their retirement, some Di 3 were sold to private railways, some of them also coming to Sweden, Italy and Kosovo.

From 1968 onwards, the SJ had the T44 built for light freight traffic, which has four axles and a central cab. The engine is an EMD 645 series two-stroke with twelve cylinders. With a production run of 123 in 21 years, it is the most numerous diesel locomotive that the SJ has ever purchased. In addition to freight traffic, they were also used in shunting and, if necessary, in front of passenger trains. In the new millennium, a large number came to private operators, most of them to Green Cargo. The decision was made there in 2007 to equip 100 locomotives with new four-stroke engines and to modernize them in other areas. By 2012, 62 units had been rebuilt in this form and were now given the designation Td.