In 1902, the SBB inherited a total of 66 shunting steam locomotives of the E 3/3 type from its predecessor railways. Of these, three were from the United Swiss Railways (Nos. 8395–8397), 36 from the Swiss Central Railway (Nos. 8398, 8399, 8401–8425, 8581–8589 ), 16 from the Jura-Simplon Railway (Nos. 8431–8440, 8571–8576) and 11 from the Swiss Northeastern Railway (Nos. 8551–8559, 8661, 8662).[1]
The fleet of E 3/3s inherited from the SBB's predecessors were not sufficient at their task, meaning that the SBB had to procure additional locomotives in order to gradually equip all railway stations, larger stations and connecting facilities with a powerful shunting locomotive. Previously, former mainline locomotives had been used for this purpose, but they were not nearly as maneuverable.
Owing to coal shortage during the Second World War, in 1942/1943, locomotives No.8521 and 8522 were equipped with an electric boiler heating system fed from the overhead line and pantographs on the driver's cab. The electrical equipment was sourced from Brown, Boveri & Cie. and the SBB workshop in Yverdon installed the equipment on No.8521 on 13 January 1943, and on No.8522 on 11 February 1943. Both locomotives had their electrical heaters removed in July 1951 and 24 April 1953 respectively.[6] The latter has survived into preservation, and is operational on the Sursee-Triengen Railway.