How about hauling 100 Class 8
trucks, fully loaded—4,000 tons—in one go? That's
the kind of load Shaughnessy & Company of Auburn, Washington,
handled this past summer. Since 1909, Shaughnessy has been
one of the world's premier heavy riggers and haulers, and
one of its mottoes is "Accomplishing the unusual and
difficult." We'll look at their move of a 3,250 ton
dragline at a coal mine in Centralia, Washington, and see
some of Shaughnessy's other "Heavy Hauls of Fame.".
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Shaughnessy
& Co. specializes in heavy hauls, like this move of
an entire theater on the University of Washington campus. |
| Typical
of Shaughnessy & Company's work is this move of a
3,250 ton dragline at a coal mine in Centralia, Washington. |
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Fred McFall, vice president and general manager,
Shaughnessy & Company: "For us, it's hundreds or
even thousands of tons. By comparison, a regular over-the-road
truck usually weighs no more than 40 tons.
"We move airplanes, sections of bridges and giant pieces
of industrial equipment. And, once we get it where you want
it, we put it in place for you."
How is Shaughnessy's work different from trucking?
"The loads are a lot heavier, and we generally move
at very slow speeds. Often, we don't use tractors or trucks,
but special, self-propelled modular platforms that we custom-assemble
for the particular job.
"And, unlike the trucking business, we sometimes have
to make our own roadbeds. But once you get past those things,
it still involves loading stuff onto some sort of wheeled
platform, then moving it to a new location.
What kind of "wheels" do you use?
"There, we are a lot like the trucking business. Our
platforms usually ride on rubber tires, just like they do."
Are they special tires?
"Not always. For example, when we moved the dragline
at the Centralia coal mine, we used Bridgestone M857 radials,
which you might find on a construction truck. Of course,
we use quite a few more than a truck, but the principle
is the same.
"So far, compressed air inside a rubber tire is still
one of the best ways to support and transport a load."
How many tires were involved in the Centralia move?
"The platform we assembled had 432 tires, and
was composed of 24 modules. Each of these modules
is a sort of platform in itself, about eight feet
wide, with either four or five axles, and each axle
has four tires. There were six 'power packs.' These
have diesel engines that provide the power for the
hydraulic drive system.
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As the dragline approached the bridge,
there was just six inches of clearance between the
side barriers and the transporter. |
"Each power unit is capable of delivering about 500 horsepower,
a bit more than a typical semi truck. With that many tires
and wheels, steering is very complicated, so it's controlled
by a computer that precisely angles each wheel during turns.
The 'driver' sits in a cab we attach to the platform, and
'steers' with a control like a joystick."
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How did you load the dragline onto the platform?
"That was quite a job in itself. The dragline has 'feet,'
and literally can 'walk' from place to place, much like a
child's wind-up toy. In fact, the mine considered simply walking
the dragline to its new location.
"Unfortunately, both a river and a bridge were between
them. They'd have had to build a new road to cross the river,
because the bridge wasn't wide enough for the dragline to
cross. They even considered completely disassembling the machine,
trucking all the parts to the new location, then reassembling
it there.
"After some study, our solution was to move the entire
unit as one enormous load. Basically, what we did was drive
our platform under the dragline, then raise the platform so
that we lifted the 'shoes' of the dragline off the ground."
How much did it weigh?
"The dragline is over 3,250 tons, and the platform weighed
over 900 tons. Together, the gross weight was 8,400,000 pounds.
And all of it was supported by the air in just 432 tires.
"That's about 20,000 pounds—10 tons—or about
a quarter of the weight of a fully loaded semi, per tire."
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| The very first Boeing 777 left the
ground for the first time on a Shaughnessy trailer, on
its way from assembly to testing facilities. |
Per tire? How could a single tire carry that kind of load?
"The tires are more than capable of it. The trick is
that you have to have the right inflation pressure and move
very slowly. Of course, when you're moving something that
large and that heavy, you want to move slowly. And, it took
us two days to move the five miles between the old and new
locations."[Editor's Note: See related story, "Technically
Speaking," in this issue of Real Answers.]
What did you do about the bridge problem?
"We drove our platform across it. With the 'feet' of
the dragline in the air, our transporter was narrow enough
to cross the bridge. The feet hung over the sides of the bridge
(about 25 feet on each side), and we had less than 6 inches
of clearance between our transporter and the side barriers.
Another reason computerized steering is so important."
And after that, it was clear sailing?
"Not exactly. We had to keep stopping to let power company
crews drop and reinstall power lines, because the dragline
was too tall to pass under them. We also had to make turns
of up to 60 degrees and climb grades of over 6 percent.
"Heavy rains created a soft shoulder on one side of the
road, and we had to crowd the opposite side so closely that
w needed to relocate a group of light poles.
"Finally, we arrived at the new location and reversed
our original steps, so we could drive the trnsporter out from
under the dragline. After that, the dragline was ready to
'walk' away and start its work again."
Would you say this was a "routine" move for you?
"Well nothing we do is really routine, but this job
went pretty well. We got the machine moved—on time and
on budget—with no accidents, no injuries and no damage.
so, we lived up to our motto: 'Accomplishing the unusual and
difficult.'"
Editor's note: Shaughnessy & Company won the Specialized
Carriers & Riggers Association 1998 "Haul of the
Year" award for this job.
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