The A1AA1A 68000 was a series of mixed-traffic diesel locomotives introduced in 1963 which were suitable for traffic on both main and secondary lines. Due to their heavy steam heating boiler, they weighed 105 tonnes and needed six axles in total. The bogies had a A1A wheel arrangement, what meant two powered axles on the ends and a central unpowered carrying axle. The suspension of the central axles could be switched to change the load on the driven axles between 18 and 20 tonnes.

In total, 81 were built in the 68000 number range with a Sulzer 12 LDA 24 and 29 in the 68500 number range were built with a SACM AGO DSHR 2700, both delivering 1,985 kW or 2,700 hp. With later refurbishments, some locomotives got the other engine type, effectively rebuilding them into the other class.

With the introduction of more powerful four and six axle locomotives in the mid-seventies, they were no longer used for passenger service. Some even got their steam heating boilers removed and replaced by ballast weights. After only being used for freight and work trains for a long time, they were shortly re-introduced into passenger service in the nineties due to a shortage of rolling stock, where they were used double-headed. Today, nearly have been withdrawn.

The BB 63000, which was known as the 040 DE before it was redesignated in 1962, was created to replace medium-powered steam locomotives. They were four-axle diesel-electric locomotives with one driver's cab and asymmetrical hoods. A six-cylinder inline engine from Sulzer was used as the power plant, which delivered 600, 725 or 750 hp depending on the production batch. 250 examples of this series were built, but there were also almost identical locomotives in other railway administrations, which were either delivered from France or were manufactured under license. These were the class 850 in Luxembourg, the class 642 in Yugoslavia, the class 10700 in Spain (later renumbered 307) and the class 1200 in Portugal. The BB 63400 and 63500 are variants with a V12 engine from the Société Alsacienne de Constructions Mécaniques (SACM). Of the latter, 603 pieces were made.

The locomotives were also called “Deux Cheveaux” due to their large number and their wide range of applications in reference to the also ubiquitous Citroën 2CV. Although the design with a single driver's cab is more associated with shunting locomotives in Germany, they were also used in mainline service with passenger and freight trains. After a few decades in service, the area of application shifted to freight trains and finally they were used almost exclusively for shunting tasks and with work trains. The Sulzer locomotives were phased out by 2006, but 61 of the SACM locomotives were still in use at the end of October 2019. A total of 23 units were converted into the BB 64700 shunting locomotive between 1989 and 1993, with new MTU 8V 4000 engines. In another 19 units, the diesel engine and driver's cab were removed and the frame was shortened so that they now only have the traction motors. These vehicles, designated as TBB 64800, were each coupled to a BB 64700 and received the power for propulsion from their diesel engine.

As a stronger addition to the BB 63000, the BB 66000 was created with basically the same structure. The first 40 locomotives still bore the designation 040 DG and were re-designated in 1962, a total of 318 units were built. While the BB 63400 and BB 63500 got a V12 engine from SACM, the BB 66000 had a V16 from the same family with 1,400 hp. The first engines were delivered with a top speed of 105 km/h, but they were soon subsequently approved for 120 km/h and all others as well ex works.

From 1968, 106 BB 66400 were built, which were based on the latest BB 66000 series and were equipped for electric train heating. Already between 1960 and 1962 13 BB 66600 had been completed, which had a Pielstick engine. The first three of these were created by conversion and ten others were newly built. Between 1985 and 1991 a total of 34 BB 66000 were equipped with the same engine and designated BB 66700. They had a modified gear ratio for 80 km/h in order to increase traction and use it for shunting.

The locomotives were initially used in regular service with passenger and freight trains. Like the BB 63000, they were considered “jack of all trades”. The capabilities for multiple working were somewhat limited, since the sub-series were partly not compatible with each other. Over time, the engines were phased out of passenger service and were primarily only used for lighter freight trains.

In 2005, a total of 91 locomotives were fitted with new MTU 12V 4000 engines to extend their service life. In 2019, 64 of these were still in use, mainly in the SNCF freight and infrastructure areas. The BB 66600 with Pielstick engines had already been retired in 1997 and the last BB 66700 disappeared in 2018. At that time some of the unconverted locos with SACM engines were still assigned to the STF Infrarail.

BB 67400 designates 232 diesel-electric locomotives built between 1969 and 1975. They were the last diesel locomotives delivered to the SNCF in the 20^th century. They were based on the BB 67000, but had the same engine with more power, only one gear ratio for a top speed of 140 km/h and electric train heating. The class was designed after a total of 90 BB 67000 had also been retrofitted with electric train heating.

They were equipped for double-heading and for push-pull operation. When used in double, they were much more powerful than a single CC 72000. In freight operation, they were indispensable until the introduction of the Alstom Prima. After this, they are still being used for Intercité and commuter trains. In 2019, 100 were still in service.

The class CC 70000 designated two diesel locomotive prototypes which were intended to replace the most powerful steam locomotives. The highest possible power output was to be achieved by combining two diesel engines with an electric power transmission. The four-axle diesel-hydraulic BB 69000 of 1963 already had two Pielstick 16PA4 185 rated at somewhat over 2,000 hp each. The new locomotives from 1965 had both engines set at their maximum of 2,400 hp and needed a total of six axles due to their electric traction equipment.

Instead of giving each engine a separate generator, both worked onto the same generator. This one did not have a stator and a rotor, but had two rotors. When each engine rotated one rotor in opposite directions at its maximum 1,500 rpm, this created an effective speed of 3,000 rpm. This in turn allowed for a more powerful generator for the same size.

The bogies were similar to those of the electric CC 40100. They had one large traction motor each that powered all three axles at the same time. Like most French monomotor bogies, they allowed to switch between two gear ratios for a top speed of 85 or 140 km/h. CC 70002, the second prototype, could even change its gear ratio on the move at low speeds. But sadly, this feature was the cause for many problems.

After CC 70001 was delivered in December of 1965 and CC 70002 in July of 1966, they were initially tested in freight and passenger service. Due to many problems in the electric part, apart from the transmission problems of the second locomotive, they were not very successful. In the end the one-engine CC 72000 with only one diesel engine of 3,600 hp was more reliable and was thus selected for series production. CC 70002 was already retired in 1973 and CC 70001 was used in freight service only until 1983.