Also known as “Red Arrows”, the seven vehicles originally designated CLe 2/4 were fast electric railcars built from 1935 by the SLM. At a length of 21.5 metres, they had four axles. The two axles on one end were powered, while the pantograph and transformer were located at the other end. The first vehicle had nose-suspended motors, but all others got quill drives. For better aerodynamics, the resistors of the dynamic brake were mounted inside the double roof. At the same time, to similar diesel powered vehicles were built as CLm 2/4.

They originally had no buffers and were intended to run as single car and operated by a single person. Due to their great popularity with passengers and their limited capacity, they were soon mostly used for excursion trains instead of scheduled express trains. To provide additional capacity, all were retrofitted with regular couplers and buffers from 1944. Now they were able to haul an additional passenger car, but their weight was increased by around five tonnes, also due to the additional air brake equipment.

In 1952 and 1953, two were lengthened by nearly three metres and rebuilt on the inside to provide more comfort. While the basic variant had meanwhile been renamed to RCe 2/4, the rebuilt ones were called RBe 2/4. Soon, both were renamed to RBe 2/4 and RAe 2/4. Four were withdrawn between 1966 and 1968. Two followed in 1974 and 1984, while the first-built 1001 continued operating for SBB Historic. This one is still operational, while 1007 is also operational and numbered RBe 2/4 202 at the OeBB (Oensingen-Balsthal-Bahn). 1003 is on static display at Lucerne.