Jockeying for rush-hour position in New Glasgow, Nova Scotia got a little more challenging last July 17 when a 50-ton-capacity crane rolled down a main city street, before coming to a sudden stop at a railway overpass.
An employee of AW Leil Cranes and Equipment Ltd. was preparing to position the crane to hoist part of an historic home onto a flatbed truck. He turned a corner onto MacLean Street, a main throughway, and lost control, causing the crane to roll three blocks down a "significant incline," Sergeant Kevin Scott, a spokesperson for the New Glasgow Police Service, reported at the time.
But the crane wasn't the only piece of equipment rolling that day, Sergeant Scott said. The historic home was among the subjects of a documentary being filmed that day by the National Film Board. So everything was caught on film, preserved as it were, for years to come: the crane, reaching an estimated speed of 15 to 20 miles an hour, taking out four or five telephone poles... three power transformers... a set of traffic lights... and an awning outside a downtown business.
"The driver did his darndest and a civilian down the street is being credited with stopping traffic on a main street that intersects MacLean when he saw the crane coming," Sergeant Scott said. Fellow workers with AW Leil Cranes even tossed big chunks of wood -- measuring about six-by-six feet -- in a bid to stop the onslaught of the runaway crane. But to no avail.
That failure, albeit with the best intentions, is not a big surprise to Jeff Archbold, an engineer at the Toronto firm of Walters Forensic Engineering. Archbold has done accident recreations -- not for a 50-ton-capacity crane, but for a 65-foot boom lift.
That recreation involved starting from a stop, and then applying about 50 per cent throttle. "So it wasn't like we were gunning it," he says. At about a quarter of a mile an hour, Archbold says, the lift would have no difficulty climbing over a six-inch piece of tubular steel laying in its path.
On a 50-ton-capacity crane, he expects the wheels would be larger. "I would guess that we would have to have something about 18 inches high before it would even experience a hiccup," Archbold says, suggesting a mail or newspaper box would provide more stopping bang for the buck.
Why? When a crane climbs over something, Archbold explains, it will regain any energy it lost in mounting the object when it comes down on the other side. With a mid-sized object, the crane would start the climb, but friction between the wheel and object would not allow the crane to move quite as easily.
And bigger is not necessarily better. If the object is too large -- consider a car, for example -- "it's just going to push the car down the street," Archbold says. "It's finding that perfect height where it takes some energy to get over and on top of it."
With a crane that size rolling along at a speed of more than 10 miles per hour, he says, it's "definitely going to take a bridge to stop it."
Lucky for the operator, the railway overpass was between the crane and river, Sergeant Scott said. Luckier, still, was that at rush hour that Monday, there was surprisingly little traffic on the one-way, two-lane road.
AW Leil Cranes was ordered to provide provincial investigators with the crane's maintenance and inspection records, proof of the operator's certification, and a copy of the company's inspection report, says John Horton, an inspector with Nova Scotia's Department of Environment and Labour. The company has since complied with all orders.
When the company inspection was done, however, Horton says "they noticed that one of the maxi brakes wasn't functioning." The brake was removed and sent to an engineer to be examined.
The crane left in its wake a trail of "unidentified fluid smelling like hydraulics," Sergeant Scott reported. While investigators are still awaiting an engineer's report, Ted Belair, safety manager for AW Leil Cranes, says the company practice -- prior to the accident, and to this day -- is for workers to perform regular daily, weekly and monthly checks, in line with provincial requirements.
The daily inspection, Belair says, involves checking a list of 19 items, including load charts, the operator's proof of certification, and air control mechanisms. In addition to these checks, an engineer is brought in once a year to conduct an inspection.
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Any allegations of misconduct under the RCMP Code of Conduct are investigated, Tremblay says. Depending on the gravity of the contravention and surrounding circumstances, she adds, informal disciplinary action can include "a reprimand, a forfeiture of pay ranging up to 10 workdays, demotion, direction to resign, and dismissal from the RCMP."
None of the allegations have been proved in court.