The BCFe 4/8, later ABDe 4/8, designates electric double railcars built for the BLS group for regional traffic. Each car has two powered axles in the inner bogie with 240 hp per traction motor in the first variant. They got the nickname “Blue Arrows”, like some other railcars of the BLS. Originally built with second and third class seats, later vehicles were built with first and second class seats and the older ones were later retrofitted. This changed their designation from BCFe 4/8 to ABDe 4/8.

The first three were built in 1945 by SIG and SAAS with a top speed of 110 km/h. The next three built in 1954 and 1955 had 300 hp per traction motor and a top speed of 125 km/h. Two more followed in 1957 and five in 1964, all of which had 400 hp per traction motor. Also the three pairs of the second batch were later upgraded to the new traction motors. 

Later some received an additional driving trailer. To accomplish this, they lost the cab in one of the two cars and got a gangway in this place. With the new scheme from 1989, the ABDe 4/8 became the ABDe 535. The less powerful vehicles of the first batch were retired from 1991 and the last one was gone in 2007.