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.

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.

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.

The next electric locomotive for the Maurienne line came in 1925 from Fives-Lille, the 242 CE 1, which consisted of two halves and was the only one with power transmission by rods. Although the designation “242” is more indicative of a 2-B+B-2 loco, it still had a running axle at the end of each half. There was a large electric motor in each half, while competing locomotives featured a single or double electric motor per driven axle. The power was not transmitted to a rotating jackshaft, but to a reciprocating lever, which in turn drove the driver and coupled axles. A special approach was also taken with the electrics by dispensing with starting resistors and using a special, self-regulating starting system. Whether the special technical solutions of the 242 CE would have proven themselves in operation could not be determined conclusively, since it fell victim to an electrical fire in 1926 after a mileage of 6,889 km and could no longer be repaired. At 164 tonnes, it is still considered the heaviest electric locomotive ever built in France.

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.

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.

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.