Abstract: In a cable coupling for automatically coupling through conductors carrying electrical heating and/or control current lines between vehicles which are mechanically coupled together in a detachable manner, which coupling includes a contact box on each vehicle, each contact box containing a carrier carrying at least one electrical connector, with associated connectors in contact boxes on two vehicles coming into engagement with one another during or after mechanical coupling of the vehicles, the coupling further including optical fiber couplers for automatically coupling together optical fibers for the transmission of information, each optical fiber coupler is composed of a replaceable insert mounted in a respective carrier to be pivotable over a limited range in all directions relative to the carrier, and each insert includes: a member for holding the ends of a plurality of optical fibers in precise parallel alignment with one another and for holding, at the end of each such optical fiber, a lens element causin