system used by Amtrak on the Northeast Corridor in the USA EBICAB - a train protection system used in Norway, Sweden and other countries, including parts of Spain C-APT - (historical) a system once developed for the APT to transmit permissible speed and airtightness information History The earliest automatic train protection system were purely mechanical with a tripcock which could be connected directly to the braking system by releasing the opening a switch in the hydraulic system. There were multiple incidents where trains had overrun a stop signal but due to excessive speed still crashed despite the automatic stop. Multiple systems were invented to show the speed in the driver's cab and to provide an electronic system on the train that would prevent speeding. With the advent of high-speed trains it was generally expected that a speed indicator on line-side signals is not sufficient beyond so that all these trains need cab signalling. A combined solution to the requirements was the German LZB system that was presented in 1965. The original installations were all hard-wired logic. The first real cab electronics was presented in 1972 (named LZB L72) and a cab computer was introduced by 1980 (LZB 80). The LZB system uses a wire in the middle of the tracks that had loops at a distance of so that the position of a train was known more precisely than in any earlier system. As a result, the LZB system was not only used on high-speed tracks but also in commuter rail to increase throughput. Due to the deployment costs of the system however it was restricted to these application areas. The development of a system using the principle of passive balises with fixed or controlled information started in 1975 by LMEricson and SRT, following an incident in Norway in 1975 (Tretten). The LME/SRT system became the Ebicab system. The Ebicab system established the principles of using magnetic coupling, 27 MHz downlink from the antenna on the locomotive to energize the balises, and an uplink using 4,5 MHz to transmit information telegrams from the balises. The controlled information in the balises is encoded from statuses in the signalling system. The telegrams contains information about permitted speeds, and distances. The information is used in the on-board computer to calculate brake curves, monitor speed and eventually apply brakes. In Norway, the first line equipped with Ebicab as ATP was operational in 1983. The