In 1909, the French Midi started to electrify its line between Perpignan and Villefranche-de-Conflent with 12 kV at 16 2/3 Hertz. To find the suitable locomotive, they ordered six 1-C-1 locomotives with rod drive from different manufacturers. On the 2.2 percent incline on this line, they were required to haul a maximum load of 400 tonnes and to accelerate 100 tonnes to 60 km/h. One of these prototypes was E 3301, built in Switzerland by the SLM with electric equipment from BBC.

Even the first trials on the BLS line between Spiez and Frutigen were not a success. It was delivered to France anyway and the results were the same. So the locomotive was returned to its manufacturer, who took the opportunity to rebuild it for trials with single-axle drive. In this process that took place in 1918, its old electric equipment was completely removed and only parts of its mechanic structure was retained.

The middle axle was now powered by a Buchli drive on both sides, while another axle got a Tschanz drive, while the third former powered axle became a carrying axle. The two transformers were exchanged for a new one. The locomotive was now called Fb 2/5 and soon renamed to Be 2/5. In the following years it was operated on several lines, but more and more new electric locomotives with single-axle drive and more power soon meant that it was not needed anymore. After serving its last year as a shunter at Zurich, it was retired in 1929. After this, it was rebuilt into a self-propelled welding machine with only the Tschanz drive remaining and was used in this role until 1937.

The second generation of electric locomotives known as “BB Midi” consisted of the E 4100 and the E 4600. The E 4100 was intended for mixed service and had a shorter gear ratio than the E 4600. It was therefore used for freight and passenger trains on the lines in the Pyrenees. They were designated BB 4100 by the SNCF and were partially rebuilt into the BB 4600 in the 1950s. This meant that they could now reach 90 km/h and could also be used on flatter lines. When more locomotives were needed for freight service again, they and some original BB 4600s were converted back into the BB 4100. From the end of the seventies they were used in shunting services, where the last ones were retired in 1987.

The second generation of electric locomotives known as “BB Midi” consisted of the E 4100 and the E 4600. The E 4600 was intended for passenger service and had a longer gear ratio than the E 4100. It was therefore mostly used for passenger trains on the lines in the Pyrenees. They were designated BB 4600 by the SNCF and in the fifties, their number grew when a greater number of BB 4100 was rebuilt into the BB 4600 to use them for fast freight service. But after running fast with heavy trains had resulted in damage, some original or rebuilt BB 4600 were rebuilt back to BB 4100 to be used for slower freight trains. The last ones were retired in 1984.

Since the existing B-B electric locomotives of the Midi could not reach speeds of more than 100 km/h, an express locomotive was required. As in other countries at that time, the choice fell on a locomotive with driving axles mounted in the frame and carrying axles which were movable. The design of the running gear came from the E 3100 with a 2-C-2 wheel arrangement and was expanded to include an additional driving axle. 

The first series of six machines was delivered by CEF in 1932 and had a transmission that also came from CEF. Alsthom delivered 18 more in 1935 and 1936. These had the AEG Kleinow spring pot drive, which could be used thanks to German war reparations. Although the electrical equipment was reliable, the chassis design showed deficiencies. Since the centering devices of the bogies were too strong, the rails suffered heavy wear and the running characteristics at speed were poor.

Due to the problems with the chassis, the maximum speed was reduced first to 110, then to 105 and finally to 100 km/h. Thus the locomotives, which from 1938 were used by the SNCF as 2D2 5001 to 5024, no longer had any advantages over their predecessors with the B-B wheel arrangement. From 1939 they were only used in front of normal passenger and freight trains. After attempts to improve the running gear failed in 1951 and the CC 7100 was soon ready for use, they were almost exclusively used in front of freight trains. Their service finally ended in 1969.

For express trains on the line between Paris and Le Mans, the État received 23 locomotives between 1936 and 1938 which were numbered E 501 to E 523. They were directly based on the E 501 to E 550 of the PO, the later SNCF 2D2 5500. The most obvious change was the streamlined body that had been designed by Henri Pacon and didn't have small hoods. With their single headlight, they got the nickname “Cyclops”.

Like their predecessors, they had a 2-D-2 wheel arrangement and Buchli drive. Since they were used on a flatter line, they only had a rheostatic instead of a regenerative brake. The top speed was originally limited to 130 km/h, but was later increased to 140 km/h after the installation of roller bearings.

When SNCF was founded in 1938, they were designated 2D2 5400. In World War II, two locomotives which had been damaged were rebuilt into a new one. When parts of the line between Paris and Le Mans were electrified with 25 kV AC and operated by dual-system locomotives in the sixties, the 2D2 5400 were transferred to the south western region. Withdrawals were between 1975 and 1978.

Fives-Lille supplied the ten freight locomotives 161 DE 1 to 10, which again consisted of two halves. In each half of the locomotive, three powered axles were mounted in the frame, which, like the 161 CE, were supplemented by a movably mounted leading axle. The weight distribution was designed in such a way that the leading axles each had to carry less than ten tonnes and therefore more adhesion mass was available. Instead of platforms at the ends of the locomotives, there were smaller hoods, while the doors were attached to the sides. When the locos were taken over by the SNCF, they became the 1CC1 3801 to 3810. The last examples remained in service until 1973.

A special feature of the series came about during the war, when 1CC1 3805 fell victim to a bomb attack in Modane. Only one half of the locomotive was badly damaged, while the other remained largely intact. It was not until 1949 that the intact half was refurbished and used as an independent locomotive with the number 1C 1001 in shunting operations in Saint-Jean-de-Maurienne. The contact shoes for the third rail were removed so that the locomotive could only work under the catenary. The continuous output was increased to 1,070 kW and use ended in 1966.

One of the four trial locomotives on the Mont Cenis line was the 161 AE 1, supplied by Schneider and Alsthom. It shared the total number of eight axles with the 242 BE 1 and 242 AE 1, but the body was divided into two parts, as with the 242 CE 1. In contrast to all the others, however, six axles were powered and only two axles were used as carrying axles. This was realized by mount each half of the locomotive on two bogies, of which the outer one consisted of a carrying and a driving axle. The power came from axle-mounted motors with spring-loaded gears that allowed 110 km/h. It was later reclassified as 1ABBA1 3500 and remained in service until 1967.

The 161 AE 1 was the only one of the four locomotives from trial operation that was reordered in a total of ten units as a direct development. The production locomotives were designated differently as 161 BE, since they were intended for use in front of freight trains. In return, they got simple axle-mounted motors without spring-loaded gears and a different gear ratio, which only allowed a maximum speed of 80 km/h. The hourly and continuous output was increased by 90 and 110 kW, respectively, and the weight also increased. The SNCF used the locomotives until 1973 and named them 1ABBA1 3601 to 3610.

After the 161 AE proved to be the best of the four test locomotives on the Maurienne line, each ten locomotives with a total of six powered axles and only two carrying axles were ordered from SACM and Fives-Lille, the electrical parts of which were designed by CEF (Constructions électriques de France). SACM's contribution was the 161 CE, which had a one-piece body. In contrast to the 161 AE and BE, three powered axles were mounted in a bogie. The carrying axle at each end of the locomotive was designed to be radially adjustable.

The locomotive body did not have small hoods at the ends, but platforms with doors on the front. The continuous output was only 1,170 kW, but was sufficient for freight trains. The locomotives remained in use on the original line for most of their lives, only four were temporarily relocated during the Second World War. Their SNCF numbers were 1CC1 3701 to 3710. They were retired between 1967 and 1972 and then all were scrapped.

SACM delivered a test locomotive with the number 242 AE 1, which was similar in design to the 242 BE 1. It also stood on two chassis that were closely coupled to each other, each consisting of two powered axles and a two-axle lead bogie. Like the BE 1, the AE 1 also got single-axle drive with fully sprung engines. The special feature here was that the bogies had a different version of the quill drive. While one had a Westinghouse quill drive, the other got a special drive developed by SACM with a joint mechanism and the so-called “dancing ring”. This drive was later further developed by SACM and Alsthom and used in the record locomotive CC 7100 and several Italian locomotives. However, the 242 AE 1 had no direct successor and was used on the Mont Cenis railway as SNCF 2BB2 3201 until 1967.

The first electric locomotive for trial operation on the Maurienne was the 242 BE 1, which was delivered in April 1925 before the electrification of this route was completed. It was therefore initially operated on the Paris-Orléans network until it was transferred to the correct route in July. The locomotive had two two-axle powered bogies that were closely coupled to each other to transmit the tractive forces. Each axle was driven by a double motor and an Oerlikon quill drive. To improve the running characteristics and to absorb the mass, a bogie with two carrying axles was added at each end. The locomotive body was in one piece, but at each end of the locomotive, like the crocodile locomotives, there was a small front hood that was mounted on the bogies. 

After testing, it was used on passenger trains until 1934 and then on freight trains. In the meantime, the larger 262 AE had emerged as a direct derivative, since the 242 BE had proven itself in service. The latter was given the number 2BB2 3301 when it was taken over by the SNCF. It was damaged by a voltage flashover in 1961 and was initially parked. Since no repairs were made, it was scrapped some time later.