9 Water level gauges; locomotive electronic equipment and electromechanical controls for use in passenger and freight rail cars, locomotives and buses, namely - inverters; power converters; switches; event recorders; traction and excitation control systems comprised primarily of electrical power supplies, applied microprocessors and solid state electronics, transceivers, transducers, solenoids, and sensors for controlling and monitoring train propulsion, braking and rail lubrication; passenger door opening systems, comprised primarily of electric and pneumatic door actuators, electromechanical controls, door panels, mechanical linkages and mechanical seals for use in buses and rail passenger cars; monitoring and communications systems, comprised primarily of automatic monitors and recorders for detecting train performance, namely - fuel level and consumption, speed, braking, electronic and mechanical train integrity; End-of-Train pneumatic valves that allow locomotive engineer to observe brake pressures at the rear of train and initiate brake applications at that location; and data radios that support communication between the systems; structural parts for all of the foregoing; parts for locomotives, freight and transit vehicles, namely - power pack assemblies; current collectors; manual and automated single car test equipment, namely - automatic, microprocessor-based single car testers that perform diagnostic tests on a rail car's brake system to determine that it is in good working order; and high voltage cabinets and control stands for locomotives; empty/load equipment in the nature of mechanical and pneumatic sensors that sense the degree of loading of freight rail cars and adjust the applied braking force to properly compensate for rail car loading