TransLink was very lucky that this accident happened at the end of the line in Surrey, with an apparently empty train. A brake caliper fell onto the track and was large enough to derail the next train that passed by. Here lies the Achilles heel of automatic transit systems, they can’t see obstructions on the track and proceed to hit them, sometimes with disastrous results.
TransLink is now operating a fleet of 25 year old vehicles and as with most older transit vehicles, if preventive maintenance is not done more frequently, this sort of thing will happen and with increasing regularity. This should be a wake up call for TransLink, that yes, SkyTrain is railway and derailments do happen and the older fleet of Mk.1 cars will need a more intensive maintenance schedule, which of course will raise operating costs and that is something the cash strapped TransLink doesn’t want .
And now a final niggle at TransLink, if this was LRT and if there was a driver, a piece of scrap metal large enough to derail a SkyTrain car, would have probably have been seen by the driver, who would have stopped the tram, preventing a derailment.

TransLink investigates SkyTrain derailment
By Kelly Sinoski, Vancouver Sun
May 28, 2010 3:02 PM
METRO VANCOUVER — TransLink is trying to figure out how one of its SkyTrains lost a piece of its brake on the Expo line tracks Wednesday, leading to the derailment of a second train and the closure of a section of track for five hours.
Doug Kelsey, president of B.C. Rapid Transit Co., said the second train was out of service and pulling into the turnaround section of track — past the King George SkyTrain station — on Wednesday morning when it struck a brake caliper lodged in the track. The collision forced one of the train’s axles to jump out of the track and derail.
No one was aboard as the train was in the no-passenger zone, Kelsey said, so there was no risk to the public. The train had been travelling between four and eight kilometres an hour.
“This has never happened before, in 25 years,” Kelsey said. “We’re quite perplexed by it.”
Meanwhile, the first train, which had continued on the route, was stopped at either the King George or Surrey Central stations and placed in quarantine, Kelsey said, while the section of track between Gateway and King George stations was closed. A bus bridge set up to ferry passengers to the Surrey Central or King George stations.
The tracks were reopened at 4:05 p.m. just before rush hour.
Kelsey noted the travelling public was never in jeopardy as SkyTrains have a multiple braking system — including an emergency stop mechanism — in each car. The brake caliper was one of the original pieces on the SkyTrain, which has been operating since 1995.
All the trains are inspected every six weeks. The quarantined train was due for an inspection in two weeks’ time, Kelsey saidThe whole fleet has since been inspected and Kelsey said as a precaution the checks will now take place every three weeks.The train will remain in quarantine until technical staff figure out what happened. “We won’t be moving it until we determine what caused [the brake piece to fall off],” he said, but added: “The public is absolutely safe out there.”
http://www.vancouversun.com/TransLink+investigates+SkyTrain+derailment/3084244/story.html