Concrete
slab track is a ballastless alternative to conventional wood or concrete tie applications.
Common uses in today's environment include concrete paved trackways for light
rail transit located in urban streets, in railway and transit tunnels where low
track maintenance is of paramount importance, and at railroad grade crossings
to ensure smooth track crossing by automobiles and trucks. Concrete slab track
can also be utilized as the principal support structure for high-speed rail in
corridors to be shared with freight traffic. New high-speed track installations
in Europe and Japan feature the use of slab track because of its durability and
low maintenance. Slab track may be constructed directly on tunnel inverts, at-grade
over a prepared subgrade, or on aerial structures. Slab track design criteria
for projects in the US follow the guidelines established in the AREMA Manual,
Chapter 8, Part 27. Specific design solutions are performed using 3-D finite element
analysis and the PCAMats
program. In situations where higher speeds are desired, the longitudinal,
lateral, and vertical loads should be determined following the recommendations
of AREMA and the governing rail authority.
The
shape of the slab can be varied to suit design preferences. It can
be a simple flat slab or incorporate dual or single block precast
concrete ties, plinths, and embedded rail. Several other variations
include precast and prestressed jointed panels or ladder track configurations.
Construction techniques include the use of slipped form paving machines,
top down construction, grouted precast panels set on a poured slab
or the use of conventional paving machines. Globally, there are
numerous slab track tests and demonstration sites that have established
the current state-of-the-art in ballastless track construction and
shown that slab track is a viable, durable, and cost effective track
system.
Slab Track Gaining Momentum
Slab Track Research and Demonstration Project