Bus Dewirement.JPG
Last week I took on the very pressing question of why so many King County Metro electric "trolley" buses experience dewirements in front of Seattle


Comment of the Day: Anything Can Happen - Like a 'Molten Pillar of Fire'

Bus Dewirement.JPG
Last week I took on the very pressing question of why so many King County Metro electric "trolley" buses experience dewirements in front of Seattle Weekly's office. It was top-notch journalism, and naturally inspired some equally top-notch feedback from readers.

As the post noted:

Originally reached by phone earlier this week, when I told King County Metro Public Affairs Coordinator Jeff Switzer what I've witnessed - the dewirement of electric buses at this one location at least three or four times a day for the last three weeks - he agreed that such a situation isn't how it's supposed to work. While dewirements - apparently that's the technical term for them - do happen, Switzer said three to four times a day in one location would be unusual. He told me he'd make some inquiries and look into the situation.

Yesterday Switzer called me back. After poking around, he told me the location I'd identified wasn't considered a "trouble spot" for dewirements by King County Metro. Interestingly enough, on the very same day Switzer got back to me, buses seemed to be taking the slight turn from Third Avenue onto Second Avenue Ext slower - and I only witnessed one dewirement, representing a marked decrease from what had become the norm over the past three weeks (coincidence?).

Whether my sample set of three weeks perhaps represented an "oddball occurrence," as Switzer put it, is hard to say at this point. But he was able to provide some information on why dewirements happen in the first place ... and teach me a new word in the process.

According to Switzer, dewirements at Third Avenue and Second Avenue Ext can have a number of causes. In an email he explained the three most likely explanations:

A device called a fahslabend (a switch in the overhead wires activated by a radio signal - usually the coach turn signal) malfunctions, does not trip and the poles continue on the straight wires (to Third Avenue South) instead of going to the left wires onto Second Extension South.

The operator fails to keep his/her left turn signal on long enough to trip the fahslabend (there's the new word!) and the poles continue straight, eventually causing dewirement.

The operator drives too fast through the crossing wires at this location and dewires. Speed limit through crossing wires is 5 mph.

Switzer also says some dewirements could be caused by drivers with new routes learning the territory - though with the most recent changes to Metro services having kicked in Feb. 16, he indicates the bulk of the dewirements I've witnessed wouldn't have been caused by this.

Commenter fplowe writes:

Many Years Ago when I drove trolley coaches in service one of the first things I figured out was there things about trolley coaches that just couldn't be explained. When you are at the wheel of trolley coach anything is possible and ...in the words the people I worked with stuff happens! Like the time a trolley coach de wired near the Fredricks And Nelson both poles touched the positive wire and created a molten pillar of fire that came out of the sky burning a hole in a Brand New Mercedes Benz! Oops sorry about that


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