Control unit
The Master Control unit was discontinued in 1985, the Slave controller, Loco Modules, and accessory modules were still available until the late 1980s. The system is still used today by many modellers, highlighted by the demand on such sites like eBay for the items in the secondhand market. Despite being on the market for a short time, Zero 1 had the largest installed base among command control systems in the early 1980s in North America, according to a reader survey done by "Model Railroader" magazine.