When Pantographs Attack

[jwtheiv]

http://www.baltimoresun.com/news/maryla ... 4340.story

An Amtrak train tore down overhead catenary power lines in an accident near Bowie on Thursday morning, disrupting rail traffic in the area and many MARC and Amtrak riders' morning commutes, according to the Maryland Transit Administration.
Craig Schulz, an Amtrak spokesman, said the incident occurred about 9:30 a.m. and left the Northeast Corridor train No. 181 — carrying 177 passengers — without power.
About 10:30 a.m., all Penn Line MARC service was suspended. All southbound trains were stopping at BWI Thurgood Marshall Airport, where passengers were being met by buses.
No Amtrak trains were moving through the area, Schulz said.
"They're out there right now," he said of engineers about 11 a.m. "They're trying to clean it up."
Schulz said he had no estimate for when the tracks would be clear.


Read more: http://www.baltimoresun.com/news/maryla ... z2xqFbkikm

Seriously, how does this happen? Crazy pantograph malfunction?

[philmoberg]

There are several things that could have caused this. It may have been a malfunction of the catenary structure, such as a lose or broken hanger that would allow the wire to become misaligned. It may have been a broken trolley (contact) wire, which can happen when the wire is severely annealed or otherwise degraded by excessive pantograph arcing. It's also possible that there was a malfunction of the carbon insert on the pantograph itself, which if badly damaged or broken for some reason could have snagged the trolley wire and broken it. There are other potential causes, such as mechanical or structural failure of the pantograph itself, as well. Once the trolley wire no longer has the structural strength to hold the pantograph down, whatever the reason, the pantograph will extend higher and do all sorts of damage - especially at the speeds they operate through there - until it is lowered or torn off. IIRC, 60mph is 88fps: assume the train was operating at 90mph and it took a mere five seconds to react and drop the pantograph, and you've got a couple of football fields' worth of catenary turned to scrap.