Slippery rail
From Wikipedia, the free encyclopedia
Slippery rail is an adverse condition of railroads. Caused by fallen moist leaves that lie on and cling to railroad tracks, it hampers trains that travel over them. The condition can result in severe premature wear on railroad equipment, the need for trains to travel at reduced speeds and delays of railroad traffic. The condition usually occurs in Autumn months in heavily forested areas like the American Mid-Atlantic states, New England and much of the United Kingdom.<ref name="wsj">Holmes, Elizabeth. "Why your train is late when autumn leaves fall (free preview)", The Wall Street Journal online, November 21 2006. Retrieved on 2006-11-22.</ref><ref name="thejournal">Halbfinger, Caren. "'Flat wheels' deflate train commuters", The Journal News, November 21 2006. Retrieved on 2006-11-22.</ref>
Mechanically, if train wheels come in contact with wet and oily leaves, they might slip, a phenomenon known as "wheel slip". This causes the train's sensors to electronically indicate that excessive speed is occurring. In turn that instigates the track brakes to perform an emergency stop. The excessive stopping creates flat spots on the wheels, meaning they and the rail cars they support need to be serviced. The stopping of the trains also causes delays which create a "domino effect" of delays on other trains on the line. The reduced number of passenger cars frequently means overcrowding on trains.<ref name="larchmont">Silberstein, Judy. "Commuters Warned Of "Slippery Rail" Delay", Larchmont Gazette, November 15 2006. Retrieved on 2006-11-22.</ref>
Freight trains tend to be less susceptible to the effects of slippery rail. They are usually heavier and have more effective brake systems than passenger commuter trains.<ref name="wsj"/>
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[edit] Effects of slippery rail
Slippery rail has created severe disruptions of rail service, particularly in some major metropolitan areas like that of New York or Boston. In November of 2006, it was attributed to roughly one-third of all Metro-North Railroad's Hudson and Harlem lines passenger cars having to be taken out of service.<ref name="thejournal">Halbfinger, Caren. "'Flat wheels' deflate train commuters", The Journal News, November 21 2006. Retrieved on 2006-11-22.</ref> During the same period on the Long Island Rail Road, nearly twenty-five percent of the cars were out of service due to slippery rail.<ref name="wabc">"Commuters, expect train delays", WABC-TV, November 22 2006. Retrieved on 2006-11-22.</ref><ref name="yorkpress">Aitchison, Gavin. "Leaves on line cause rail delays", York Press, November 21 2006. Retrieved on 2006-11-22.</ref>
In other parts of the US, Amtrak, the Massachusetts Bay Transportation Authority, southeastern Pennsylvania's SEPTA, Chicago's commuter rail service Metra and MARC, which serves the Baltimore and Washington suburbs, have all reported delays of their services due to slippery rail.<ref name="wsj"/>
In the United Kingdom, it is estimated that the Autumn leaves problem costs the rail industry £60 million (US$115 million) a year.<ref name="yorkpress"/><ref name="natrail">Network Rail (UK) (October 16 2006). Biggest Ever Campain Unveiled for Autumn Leaf-Fall Battle. Press release. Retrieved on 2006-11-22.</ref>
[edit] Combating slippery rail
Methods for dealing with slippery rail have included cutting back trees adjacent to rails, the release of sand on the train wheels for traction, high pressure water blasting and, most expensively, the use of high powered laser blasts to clear the rails of leaves.<ref name="wsj"/>
Metro-North has designed a system dubbed "Waterworld," which is a large flat rail car that blasts the rails with high-pressure water jets as the car moves over it.<ref name="larchmont"/>
New Jersey Transit has used a similar method, which has proven quite effective. The device they use is called "Aqua-Track" which, while attached to a moving rail car, sprays water at a pressure of 689 bar (10,000 pounds per square inch) directly onto the part of the rail where the leaves cling.<ref name="wsj"/> Since implementing this system in 2002, the delays due to wheel slip have been reduced over sixty percent.<ref name="thejournal"/>
In the UK, Network Rail has plans to use satellites to locate troublesome areas for quick responses from 2-man 'leaf-busting' crews that, according to a National Rail press release, "use railhead scrubbers, sand sticks and Natrusolve, which dissolves the leaf mulch to tackle the dangerous substance."<ref name="yorkpress"/><ref name="natrail"/>
[edit] References
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