Unit 1646 at Erstfeld.
The BDe 4/4 was a series of 31 electric passenger and luggage railcars of the Swiss Federal Railways or SBB for short, built over 1952-1955. Initially, until 1956, they were designated CFe 4/4. The 4/4 in the Swiss designation system means 4 out of 4 axles are powered, in other countries the type is designated as Bo-Bo. Of the 31, 3 are preserved.