I maintain, install, inspect, test, alter, troubleshoot and repair New York City Transit railroad signal equipment system-wide. The various types of railroad signal equipment include all-electric, electro-pneumatic, all-relay and mechanical interlocking machines, centralized traffic control machines, electronic code systems, train identity systems, microprocessors, communication-based train control(CBTC), switch machines, automatic train stops, color light signals, and related power and control equipment.