Bombardier has international headquarters in Berlin and has various locations throughout the United States, including a rail transportation location in Pittsburgh. It offers a wide range of rail vehicle portfolios that include metro and light-rail vehicles, locomotives and high-speed trains. The firm supplies an extensive range of rail vehicles to operators throughout the world. It provides its support services to a variety of areas, including full train and fleet maintenance, operations and maintenance services, vehicle refurbishment and modernization, materials solutions and re-engineering and overhaul of vehicles and components. It offers various customized rail vehicle products to its operators and customers. Bombardier also provides a wide range of rail systems, including integrated control, computer and relay based interlocking, automatic train protection and train operation, radio based rail control and signalling systems and wayside equipment.