light rail vehicles
Modified LRVs For Legacy LRTs Retrofitting can be a viable alternative to purchasing new, but it’s more complex than it looks.
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By Alfred E. Fazio, P.E., Contributing Editor, with Bridget Hodgson
n light rail vehicles, advancements have occurred in articulation, low-f loor design and use of alternative vehicle technology. The latter is advocated as one means of achieving shared use of light-density railroad trackage. In a design practice that harkens back to the glory days of private transit operation, many of these improvements have been accomplished through reconfiguration/reconstruction of existing fleets. The rebuild of the original single-articulated Dallas LRV into a double-articulated car with a low-floor center section is just one example. Likewise, the morphing of the NJ Transit Kinkisharyo car from the original-build triplex (double-articulated, 70% low-floor) into a five-section-articulated multi-unit (above) is another example. Such re-creation is likely to become more common given the scarcity of federal capital
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dollars to be distributed over an everincreasing number of light rail systems. The FTA’s current emphasis on state of good repair, rather than discard and pay for new, and the Trump Administration’s desire to infuse private financing into the transit industry also encourage re-creation. The LRV, however, constitutes only one system within an integrated complex of several other engineered systems. Track, train control, station and traction power subsystems require consideration when a vehicle of different configuration, or a re-created LRV, is introduced into a railway that was designed and built for a previous generation of vehicles. These considerations extend beyond reliability of operations, as the FTA requires a formal configuration management process and, ultimately, a new safety certification for such a change. Several integration problems surface immediately with the introduction of any
new railcar. These include such items as length of station platforms, door locations and designated stopping points. The acceleration and maximum speed of a new car and the ability to maintain schedule are important, as is location of such items as train-to-wayside transducers. Other integration issues are more subtle, particularly those that relate to the change in carbody style. Railcar articulation is not a new concept; main line railroads, streetcar systems, interurbans and rapid transit utilized such concepts as far back as the 1920s. The earlier articulations, however, mounted two carbodies on a single bogie. While this caused an imbalance in wheel loadings between articulated and non-articulated bogies, and careful analysis was made of the ability of the articulated joint to accommodate vertical curves, it did not dramatically alter carbody dynamics. This type of April 2019 // Railway Age 23