Transportation: A green light for advanced train controls: Solid-state developments yield hands-off operation of second-generation systems

Train control systems have been around for more than 100 years, but only relatively recently — with advances in semiconductor and computer technology — has it been possible to talk of new generations of equipment. With the second generation has come the automated operation of trains, including their starting, stopping, opening and closing of doors, and maintaining of speed. Wayside central computers integrate and stabilize the overall system. The third generation of controls is under development and should be in revenue service by 1980. It will use microprocessors on board the train and in stations to provide greater flexibility of control, increased reliability, and superior service for passengers.