The three Ce 2/4 were the first railcars that the BLS procured in 1910. They were four-axle, each with two bogies, and one of their requirements was to also carry passenger cars. The requirement was that 45 km/h could be achieved either with a 160-tonne train at 2.7 percent or with a 240-tonne train at 1.55 percent. The car body construction part came from the Swiss wagon factory Schlieren, while the electrical part came from Oerlikon and Siemens-Schuckert. The construction was based on the vehicles of the Hamburg-Altona city and suburban railway. Although it was technically planned to equip both bogies with two traction motors each, the construction was carried out with only two traction motors in one of the bogies for reasons of weight. When used on the Spiez-Frutigen test track, they were the first railcars to be used on high-voltage alternating current.

The car body was made of wood with metal paneling. The toilet room was in the middle and behind the driver's cabs was an open vestibule. There were front doors for connecting to the train, and a second railcar could also be entered with them when operating in double. In 1936, all three railcars were converted to the Ce 4/4, which had become possible as a result of advances in electrical engineering. Four traction motors with a total of 590 instead of the previous 330 kW could now be installed, which were lighter overall than the two old motors, and the two new transformers were now significantly smaller and lighter. At the same time, the chassis was modernized and the running characteristics improved. Another modernization took place in 1950, in which the nose-suspended motors were replaced by quills. Nevertheless, their use ended in 1953 and 1954, but some parts of the electrical equipment installed in 1936 were installed in the newly built BCFe 4/8.