The data communications subsystem or DCS is an important element of a CBTC system which supports the wired and wireless data communications between a CBTC equipped train and the wayside elements such as zone controllers and the automatic train supervisory (ATS) system.
A “brown field” environment (as opposed to “green field” environment) represents an existing transit system that is already in revenue service and is being re-signaled with a new CBTC system. Such an environment typically represent the most challenging deployment for CBTC a system as it must be installed, tested and integrated in such a manner as to not adversely impact the transit agencies’ ongoing revenue service. Usually, one of the first elements of a CBTC system to be designed and deployed is the DCS. This paper will examine some lessons learned related to the DCS design, deployment, testing and commissioning for CBTC projects in a “brown field” environment with a view to improving future CBTC projects.