What does it do and how does it work?

[Anonymous]

Today as i was coming home from work ,I was stopped at the crossing.I looked down the tracks and this wasn't a train ,I wasn't for sure what it was.So as it went by it had something on the side of it that read something like U.S. Rail Association Gauge Restraint Measurement Vehicle.I've never seen this before and i was just wonderinwhat it's for.I know in my Ho layout i use a piece to measure the gauge of the tracks,,,is this just the way the prototype do it????
Thanks,Diesel

[mudchicken]

You are looking at AAR110 which began life as a Southern Pacific SD45X (EMD Demo unit)....Unit has a wheel set with a hydraulic ram under the center of the carbody exerting lateral force on the rail and measuring spread rail or rollover rail conditions under dynamic loading....built at the AAR Transportation Test Center (AAR-TTC) in Pueblo.....Not a geometry car in the conventional sense. (Ultimate real world kit-bash job?)

(Brown box with yellow stripes...sort of PRR looking.................Plasser now makes a simplified version that the railroads lease or own - JoeKoh has witnessed CSX's toy hanging around his stomping grounds)

http://www.northeast.railfan.net/images/aar110.jpg .....this critter?