May 15, 2001
N.P. Carleton

Installation of Granite Track for Short Delay Line
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	The re-installation of the granite track took place, 1-7 April, in
steps listed below.  I list them in detail, in case the next operation is
done by persons unconnected with the present one.


	1.)  We took the cover off the shipping crate while it was still
on the truck in order to see which end was which, since it was critical to
start into the building in the correct orientation.

	2.)  We cleared the path that the thing must follow in the
building.  It needs all the space at the SE end of the main room in order
to swing around under the corner of the optical table and travel down the
SW side of the room.  After negotiating the step down, it must go straight
on, putting its end under the main vacuum tank and then coming back out,
swinging its end under the exit pipes as it moves around and over to the
end of the lower room, in the area normally occupied by the end bell of
the vacuum tank.  The tank bell was stowed over against the SE wall, where
the south-telescope beam normally enters.

	3.)  To support the inner end of the granite as it is introduced
into the tank, we suspended an I-beam inside the tank by two 1/2-inch
threaded rods, extending through holes (normally plugged) that
fortuitously exist in the top of the tank.  The I-beam was about 12' long,
3" wide, and 6" deep, and accommodated a trolley to which we could attach
a heavy nylon sling from the granite.  This hardware was preserved from
the original installation.

	4.)  We lifted the crate (cover back in place) with two nylon
slings, one under each end, leading up to the tip of the right-hand fork
of a big (6'-tine) forklift.  The crate hangs parallel to the fork, with
the slings held apart by the cleats on the bottom of the crate.  The
forklift brought the crate as far into the building vestibule as possible,
poking the forks right inside the door.  We then lowered the crate,
such that the inner end came down on a dolly at the bottom of the stairs,
and the outer end on the stairs.  We then backed the lift out and picked
up just the outer end with a single sling and advanced in so as to set the
outer end onto a dolly as well.

	5.)  We rolled the crate through and around, down to the step in
the building floor.  Note that the dollies must be low enough to get under
the corner of the optical table.  With the forward end of the crate
overhanging the step, we picked up the lower end with a standard
auto-garage four-caster hydraulic jack, advanced on the jack casters, and
set the end down again on a dolly.  Moving the jack to the other end, we
lifted that, advanced, and set down again on a dolly.  Then we rolled the
crate over near the open end of the vacuum tank.  

	6.)  Because the crate is too long to put in line with the tank,
we lifted the granite beam out and set it on two rolling platforms so as
to maneuver it into position.  The lift was by the 2-ton boom crane that
we bought for the purpose, using a good aluminum spreader rig, 48" long,
that FLWO had obtained on surplus.  One rolling platform, that supported
the outer end for the whole trip into the tank, was made up of two 2-wheel
jacking trucks borrowed from the MMT and lashed together.  The other end
was a 4-wheel dolly.  The maneuvering into place was done with the granite
beam supported near floor level.  With the beam aligned with the tank, we
lifted it again with the crane, built the outer-end device up to the
appropriate height, and supported the inner end from the previously
installed trolley-I-beam arrangement.

	7.)  The granite beam now could be rolled smoothly into place, and
lowered by controlling the nuts that supported the threaded rod at the top
of the tank, on the outside.  The inner-end support plate must be
carefully leveled in the transverse direction, since it determines the
leveling of the granite.  With the granite now in place, we could remove
the sling, the trolley, and the outer rolling support, and then lower the
I-beam on down to rest on wooden blocks on top of the granite.  We could
then extend the crane boom to its maximum position and reach in to pick up
the I-beam near its center of gravity and thus back it out, rolling the
crane along.  The crane will not roll freely with a load as heavy as the
granite, but behaves well with a lighter load.

	8.)  The final step was to lift the end platform that is
cantilevered from the granite, using the crane and nylon slings, and get
it bolted back on.  The platform had been stored inside the end bell of
the vacuum tank.


	To remove the granite beam again from the tank (hopefully, not
until the final de-commissioning of IOTA) all the steps listed above in
items 8.) back through 2.) can be done in exact reverse order.  When we
did it this last time, we did not have the I-beam and trolley organized,
and hence just reached in with the crane to support the inner end of the
granite (just barely inside the c.g.) and pulled the beam out with a
come-along an inch or two at a time, setting down on wooden blocks after
each pull and resetting the lifting sling.  For the first pulls, with the
crane not able to bear nearly the full weight while near the c.g. and with
the boom extended, we took only a partial load and slid the inner end
along on the inner support plate.  This all could be done again, but
reversing the re-introduction process looks like the preferred method,
although it has not been explicitly tested.

	Since the top surface of the granite beam had to be stripped for
re-finishing on this trip, the carriages were removed before moving the
beam, and all the motor-track hardware was removed as soon as the beam was
in its crate.  Lacking the need to strip, even the carriages could be left
in place, I believe, during removal and crating.