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What makes this even
more interesting is it is obvious that when the crane was installed, labor
was cheap. The crane operator rides in a basket with the crane. When the
crane is in operation, the operator is in the basket. He or she is about
thirty feet up in the air against the south wall of the shop. The locomotive
is on the track against the north wall of the shop across from the crane
operator. Doing the removal of the rods is like a ballet. The crane operator
is closely watching the crew on the ground, waiting for hand signals,
and listening for commands. The ground crew is positioning everything
just so; at the right moment and at the right tension the nuts are removed
and the rod is lifted off and placed on the floor out of the way.
Then the ballet continues.
Now in the drop pit, the pit jack is moved into position under the axle.
The frame binder is removed from under both sides of the axle. The jack
is raised compressing the suspension springs. The rail under the wheel
set is on a pivot and is swung out of the way. Now the wheel set is lowered
below the locomotive frame. Now you need to move the wheel set out from
under the locomotive. The pit jack is on wheels and the axle set is pushed
out from under the locomotive. Remember labor being cheap when the machine
shop was built? The wheel set is pushed out by brute strength. Once the
wheel set is clear of the locomotive, the crane operator will lower the
cable, lift the wheel set up out of the pit, and place it where the ground
crew wants it. This is a heads-up operation. One false move and someone
could be seriously injured; the wheel set weighs in at about 6,000 pounds.
This was in September
2007. Once axle 2 was on shop floor, it could be examined closely and
it wasn't a pretty picture. Still on the axles were the drive boxes, which
contain the crown brasses. It was very evident that these were completely
worn out.
Locomotive 93 is
a 2-8-0 locomotive, meaning the locomotive has two pilot wheels and eight
driving wheels. The locomotive weighs 187,000 pounds of which 168,000
pounds are on the drivers. So each driver is supporting 21,000 pounds
or 10.5 tons.
The driver is on
the track supporting the 10.5 tons. This weight is transferred through
the tire to the wheel center and from the wheel center to the axle. From
the axle, the weight is transferred to the crown brass. The crown brass
is in the drive box and the drive box is in the frame with the shoes,
wedges, and spring rigging. This combination supports the weight and it
allows the locomotive wheel to move up and down as 93 goes down the track.
The key interface
is the axle to the crown brass. This simple bearing rotates with a layer
of grease separating the two parts through fluid dynamic effects. The
axle and bearing are both simple polished cylinders with a lubricant filling
the gap between them. Rather than the lubricant just "reducing friction"
between the surfaces letting one slide more easily against the other,
the lubricant is thick enough that once rotating the surfaces do not come
in contact at all. Our problem was that the bearing surfaces on both the
axle and the crown brass had imperfections that disrupted the fluid dynamics.
Short version, the axle ran hot.
Our initial plan
was to just repair axle number two. In December 2007, the axle was sent
to a machine shop and put in a lathe to turn the bearing surface. Then
another problem arose: in the process of turning the axle, cracks were
discovered. All of them could be turned out except one. To turn out this
crack would bring the axle down below its condemning limit. This was setback
but it was also a wake-up call. It forced us to step-back from the locomotive
and evaluate everything.
The axle was stamped
12-30-08 as in 1908. So after ninety-nine years, the axle was worn out
and calls to the warranty department went unanswered. Discovering that
crack started a chain reaction. First, it was decided to inspect ultrasonically
all the axles. Axle 1 was from 1908, axle number 3 had been replaced in
1944, and axle 4 was replaced in 1927. What we found were axles 1 and
3 had cracks and axle 4 needed turning but was close to its condemning
limit. In other words, all four axles needed to be replaced—this
was a game changer.
Originally, our intention
was just get 93 running again and out the door. But it was soon evident
that if we were going to do the repairs that way, it would be a fool's
errand. Baling wire and bubble gum repairs simply will not sustain locomotive
93 over the long term.
Previous repairs
had repaired the symptoms but did not tackle the reality that the locomotive
was ninety-nine years old. In addition to the axles, the drive boxes,
the crown brasses, the shoes, the wedges, the wheel centers, the tires,
the crank pins, the spring rigging, the rod bearings, the cross heads,
and the cross head guides all needed either refurbishment or replacement.
Everything was worn out; in fact, rust was found on some of the bearing
surfaces left there from when locomotive 93 spent thirty years outside
in the elements.
The deeper we got
into the locomotive the more that we found wrong. The first indication
the project would be bigger than anticipated was when we removed the tires
from the wheel centers. When the tires came off, it rained shims. This
was unexpected. Once all of the tires were off, we had a little mountain
of shims to deal with and a new unexpected problem—oversized tires.
Due to how closely
all of the pieces of the running gear must work together, repairing one
piece meant repairing another. For example, on the spring rigging the
holes in the beams are suppose to be circular; they weren't—they
were oval. And the pins that held the beams in place looked liked like
crankshafts rather than smooth rods.
The drive boxes were
the biggest challenge and this is saying a lot because the entire process
was a challenge. But the drive boxes are crucial to the entire system.
They hold the crown brasses and axles and slide up and down in the locomotive
frame. We welded them up and then machined new surfaces. Every surface
that needed machining required what is called a set-up. We stopped counting
the set-ups per box after we reached thirty-five (remember there are eight
drive boxes). It might take hours to do a set-up and then just minutes
to do the machining. To say this is labor intensive just doesn't begin
to explain it. There are eight individual boxes, but the machining needs
to take into account how all of the boxes interface with the frame.
Our commitment to
doing it right was expensive. We were taking care of problems there we
left over from the 1940's. Rebuilding a steam locomotive in the twenty-first
century is a massive undertaking and not for the faint of heart. You just
don't go to Auto Zone for parts. Locomotive 93's parts needed to be custom
made, machined, fitted, checked, machined again, fitted, and checked.
This is craftsmanship on a huge scale; the tolerances are unbelievably
precise and the pieces are enormous.
But due to the combined
efforts of the Heber Valley Railroad, Bonneville Machine Shop, Gary's
Machine Shop, and our staff and volunteers the running gear of locomotive
93 is better today than when she left her builder, the American Locomotive
Company, a century ago.
On January 17, 2009
the Governor of the State of Nevada rededicated locomotive 93 at her 100th
birthday party. "Engine 93, the fourth locomotive of the monster
freight type ordered for ore line service…" and the remaining survivor
is now ready for her second century of service.
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