In 1952, the SLM built two heavy electric shunters which were based on the Ee 3/3. They were crocodile locomotives, with the cab, transformer and pantograph located on the central bridge frame. The running gear at each end was similar to one Ee 3/3, meaning that it had three axles and one traction motor that transmitted its power via a crank axle and rods.
No more were built when it was decided that surplus Ce 6/8II could be rebuilt to shunters. Most of their lives, the two were used in Basle. When the Ee 6/6II was introduced in 1980, they were renamed to Ee 6/6I. In 1998, 16802 was retired after it suffered damage to a traction motor. 16801 was retired in 2005.