Engineering a Slab Track System to Increase Adjustability and Reduce Construction Time
(Room Sagamore 6)
19 Sep 17
11:00 AM
-
11:30 AM
Tracks:
AREMA Technical Sessions- P&T
Light rail and transit rail systems frequently use slab track, or ballastless track, when viaducts or tunnels are necessary to separate the track structure from grade level. Track adjustability and construction time are critical parameters that affect the efficiency of slab track systems. Metrorrey, the transit agency in Monterrey, Mexico, recently completed construction of Line 3. Metrorrey leveraged several recent advances in railroad track component technology to increase track adjustability and reduce construction time using a precast concrete rail seat block and modular fastening system. Track adjustability is important for slab track systems to compensate for construction errors or viaduct/tunnel settlement. Metrorrey selected the block and modular fastening system because the components can be exchanged to adjust track gauge (+/- 12.5 mm) or added to adjust the vertical position of the rail (+ 60 mm / - 4 mm). Metrorrey sought to reduce construction time, which was critical to the success of the aggressive construction schedule. The block and fasteners reduced the construction time by eliminating one or more steps in top-down slab track construction. The block was cast directly into the plinth, removing the need for temporary fastening components or grout to establish the fastener position. This paper will include a summary of the lessons learned from Metrorrey’s recent experience implementing the new technology. Additionally, the paper will include a review of the conceptual design of the precast rail seat block and a comparison to existing slab track technologies.