High-efficiency decoder for converting single-motor Maxi locomotives to the high-efficiency propulsion system. This electronic circuit has a total of 4 controllable functions. The "function" output is intended for headlights. The "f1" and "f2" outputs can be used for other functions such as a sound system or a smoke generator. The "f4" function enables you to turn off the load-dependent speed control feature for easier switching maneuvers. The "f1", "f2" and "f4" functions can be turned on and off only with a Control Unit (6021) or with a Control 80 f locomotive controller or an Interface connected to this central unit. This electronic circuit offers the potential to adjust maximum speed as well as acceleration and braking delay. This circuit has built-in load-dependent speed control for different load situations such as ascending and descending grades. It can be coded for 80 different locomotive addresses. When operated with AC power or with the 6607 Delta Station, the "function" and "f1" functions are turned on. Decoder dimensions 43 x 25 x 8 mm / 1-11/16" x 1" x 5/16".