In the eighties, the Belgian State Railways had 140 type AM 80 multiple units built for passenger transport at speeds of up to 160 km/h. They initially consisted of a motor car with all axles powered and a control car. The automatic couplers are only compatible with other vehicles of the same type, but allow up to six motor cars to be combined. In order to increase the capacity, additional trailers were added from 1992 and the power was increased a little. The trains are not only used in intercity and interregio traffic, but also as regular passenger trains. Even after modernization from 2009, the vehicles do not have air conditioning, which is why they have not been in high-quality service since then.

The Type 608 formed a series of six railcars with internal-combustion engines that were delivered by Forges Usines et Fonderies d'Haine-Saint-Pierre shortly before the Second World War. These vehicles were streamlined at both ends, intended for fast traffic without a trailer cars. They were built under license by Ganz in Budapest and offered ten seats in second class and 54 in third class. Both axles of each bogie were driven by an 500 hp eight-cylinder diesel engine via mechanical transmission. 

The six railcars were preceded by a Type 607 prototype that had been delivered in 1936. The Type 608 series vehicles were ordered together with the two-car type 553 railcars and delivered in 1939. They achieved a speed of up to 126 km/h in test drives, but were limited to 85 km/h in service. In contrast to other Belgian railcars, some of them survived the Second World War. It is thanks to this fact that the 608.05 can be visited in the railway museum in Treignes after a refurbishment and is therefore one of only two pre-war Belgian railcars that are still preserved today.

During the Second World War, the Belgian State Railways had 50 type 553 railbuses manufactured at Brossel. They represented the third generation of railbuses from this manufacturer and were based on a prototype from 1939, which had been designated as type 552. Although the vehicles were not much longer than the German railbuses of the post-war period, they had two bogies, each of which a powered inner axle. The power for this came from an eight-cylinder in-line engine, which, like the vehicles, came directly from Brossel.

Some of the 50 vehicles of the type 553 were destroyed during the war, which is why initially ten and later another ten of the successor type 554 were built from 1950. These differed from their predecessors not only with a different car body, but also with better insulation and the toilet. While the older vehicles were later redesignated as MW 49, the newer ones became MW 46. In the 1970s, the latter received new two-stroke diesel engines from Detroit diesel with only 178 hp instead of 226 hp. The vehicles were phased out between 1985 and 1994, some of them were later used in construction trains. Only two of the 50 units of the type 553 were preserved, while about half of the 20 units of the class 554 are still preserved today.

In order to replace the passenger transport capacity on branch lines that was lost during the Second World War, the Belgian state railways procured four-axle diesel railcars of the types 602 and 603 from 1954. A diesel engine from Carels with an output of 400 hp was used as the power plant. The vehicles stood on two bogies, only one of which was driven on the inner axle. This limited their field of application to routes in the lowlands. The differences between the two series were limited to the design of the interior. While the Type 602 also had a first-class compartment and a luggage compartment, the Type 603 only had second-class seats.

The order included six Type 602s and 30 Type 603s. The former served as a feeder to Brussels Airport, while the others served on secondary routes. In addition to the motor cars, trailers were also ordered, which were designated as Type 732 and 734 and had two or four axles.

Types 602 and 603 were later renamed MW 42 and MW 43. After the feeder to Brussels Airport was electrified, the MW 42 were converted into MW 43. As vehicles got older, some vehicles were fitted with General Motors two-stroke diesel engines. This resulted in the MW 44 on the one hand, which was given an engine consisting of two combined four-cylinders and still only driving one axle. In addition, the MW 45 was created, which received two individual six-cylinder engines, each with 165 hp, each driving one axle of each bogie. Other vehicles were converted into railway service vehicles in the 1980s. The last remotorized vehicles were in service until 2002 and were then replaced by the MW 41.