By the mid-Forties, only electric locomotives with side rod drive were in operation under catenary on the Rhaetian Railroad (RhB). In 1944, the RhB decided to make a leap forward and ordered four modern electric locomotives with trucks from SLM, road numbers Ge 4/4 I 601-604, which resembled road numbers Ae 4/4 251 and 252 of the BLS in many ways. On the electrical part of the locomotives, a tapped transformer supplied power to the four traction motors and all the units were equipped with regenerative brakes, which served to brake the locomotives and half of the load coupled to them on lines with 3.5 and 4.5% grades. After very satisfactory performance from the units delivered starting in mid-1947, the RhB ordered another six units in 1953 (road numbers Ge 4/4 I 605-610). After almost four decades in the green paint scheme, many components had to be renewed starting in the mid-Eighties. The locomotives were given roomier cabs with new ends, new transformer windings, and renewed wiring, equipment for multiple unit and remote control as well as the now current, red RhB paint scheme. With the delivery of new units, six locomotives (road numbers 601, 604, and 606-609) had to be taken out of service in 2010/11 and were scrapped. The remaining four locomotives have been used since 2015 with the construction trains for the new construction of the Albula Tunnel or as a reserve among other things.