40 years in service now are the heavy diesel-electric shunting locomotives Am 6/6 of the SBB. 6 (# 18521-18526) of this 1440 kW locomotives were built in 1976 by Thyssen Henschel and BBC mainly for shoving freight trains over the hump in the Limmattal shunting yard, 5 are still operational. The prime mover is a 16 cylinder SEMT-Pielstick with 1840 kW, max velocity 85 km/h.