Answers for cities. Thanks to its new “Trainguard MT CBTC” system, Siemens has achieved a worldwide first in terms of resignalling a line operating 24/7. The Siemens Automatic Train Control system has just been put into revenue service for the first time on the whole Canarsie Line (“L” Line) New York subway’s. This takes place after seven years of work with uninterrupted passenger service. In the framework of a contract with the New York City Transit Authority (NYCT), Siemens was chosen to establish the network modernization standards : definition of the CBTC system and specifications for interoperability standards. Eventually, the whole New York network will be modernized to meet these specifications. This is the first Automatic Train Control (ATC) system in New York, whose performance now makes it possible to improve system safety, increase train frequency and simplify maintenance. The extremely difficult site conditions have made the achievement of this project a real challenge, which was completed on time. Siemens supplied the following for the Canarsie Line: ◊ The Trainguard MT CBTC system including wayside equipment, on-board equipment (including the Optical Speed Measurement System) and radio communication equipment (Airlink), ◊ The Operation Control Center. In the case of New York, Trainguard MT CBTC overlays the conventional signaling system. Furthermore, this is the first time loop communication equipment has been replaced by digital radio communications, simplifying the track equipment significantly. Speed measurement has also benefited from a new technology: a LASERbased rail reading system. New York City (USA) L Line (Canarsie line) World first resignalling line with Communications-Based Train Control