Jim's Holiday report

BRIDGEPORT, Conn. – The engineer of a Metro-North commuter train that derailed Friday evening in Bridgeport striking an opposing train saw a broken rail before the incident, WCBS-TV reports. The incident injured passengers on both trains, damaged two sets of new M-8 commuter cars, and shut down a segment of the Northeast Corridor for four days.

If that’s true, there is good reason for National Transportation Safety Board investigators to focus on the broken rails they’ve found in the wreckage of the collision. Modern steel rails are made to withstand millions of pounds of trains a day, but can snap under the weight of even a light load if poor maintenance and neglect enabled them to become brittle with use.

The obvious question is why, but the answer isn't so simple.

Steel objects will break with the right amount of physical stress. Steel paperclips, for example, will snap when bent over and over because the place where it bends becomes brittle. Engineers call the bending process plastic deformation.

Another form of plastic deformation is the kind found in work-hardened metals, such as old drill bits or hammers with cracks or chips where the metal is thin. They chip because they are becoming brittle with use.

The same can happen in rails. The friction generated by rolling stock at speed, combined with the weight of the freight or passenger cars moving overhead eventually causes brittleness and cracks known in the industry as rolling contact fatigue. Left untreated, brittleness spreads through the rail to the point that the rail or a piece of rail will break off.

When it does, accidents like Bridgeport can happen.

Even so, a broken rail in signaled territory will also break an electrical circuit and cause the signals to indicate stop before a train can roll through the block. Michael McGinley, a retired railroad civil engineer and former Southern Pacific trainmaster tells Trains News Wire it's possible that a broken rail could have kept the signal intact. Rolling contact fatigue, for instance, might have weakened and crumbled just the head of the rail, making it appear broken through, but intact enough for signal current to flow. McGinley also says that a break in any electrically isolated rails, as in bolted connections between welded rail sections, will also keep signals from showing stop.

10, Could the worm be turning for Amtrak?

http://www.railwayage.com/index.php/blogs/frank-n-wilner/could-the-worm-be-turning-for-amtrak.html?channel=

11. Congressmen announce Public Transportation Caucus

http://utu.org/2013/05/24/congressmen-announce-public-transportation-caucus/

12. Responding to highway bridge collapse, Amtrak to add one daily round trip

http://www.king5.com/news/local/Amtrak-adding-1-daily-round-trip-n-of-Seattle-208905861.html

13. NARP May 24^th Hotline

http://www.narprail.org/news/hotline/2237-hotline-812-may-24-2013

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My reality check just bounced!

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