Project Description
Parsons was selected as prime consultant, replacing the previous consultant team, for systems design engineering for the North Central and Northeast Lines build-out of the Dallas LRT. Services include design, procurement, and installation management; as well as testing and start-up of all wayside systems elements, for these two major extensions to the DART starter system. The work also includes design support to DART to help correct deficiencies found once operations begin, with system elements of the starter line to include fare collection and signaling elements.
The project scope includes design and construction management for traction power, catenary/OCS, signals, and corrosion/stray current control for approximately 24 miles of line extensions. The yard and service and inspection (S&I) facility will accommodate an increased fleet of 125 cars.
One of the unique features of the DART system is the use of thyristor controlled rectifiers for the traction power system. Parsons' TRACPAC simulation program has been used to model the TCR system to provide optimized spacings for the new substations. The signaling system uses conventional block signals with Train to Wayside Communications (TWC) to trigger crossing gates adjacent to passenger stations and for route selection. Another unique feature of Parsons' innovative systems design is the construction staging that is required.
The Northeast Extension will involve the installation of a diverging interlocking outside of a below grade passenger station. This extension requires that it be constructed over an existing interim station, which must remain in service as a terminal. Accordingly, it will be staged as three discrete segments in order to expedite the opening of new service to expanding population and employment centers.
The signal design work includes development of interlocking and control panel layouts, wayside block signal layouts, relay and microprocessor-based controls, and simulations of train and traffic signal systems.
| 
