12/20/01 rev 03/07/07
We are evolving our modular HO layout to depict the Oregon Short Line (aka Union Pacific) history of the Pocatello Idaho in keeping with our Society's obligation to serve the historical interest of our community.
Nothing like taking on a big project first thing, so we opted to replicate the nearly full circle roundhouse that was nearby once upon a time. We have two quality photos taken in 1914 and 1929 from the nearby coaling tower. No helicopters in those days.
In 1914 there were 35 stalls spaced at six degree intervals around a
100 foot turntable with six I/O tracks.
In 1929 there were 53 stalls at six degree intervals with six I/O tracks. The 60th radial is where the power pole sat that dropped electric power to the turntable gallows.
Today, the roundhouse is long gone but the 100 foot turntable is still in place and operational. It was beefed up for heavier loads around the '50s according to local old timers.
The replica had to suffer some selective rejection (AKA selective compression) because it would be too unwieldy if modeled full size. This is a working model, hence a major concern is the need to reach into the center where the turntable is. We decided the maximum reach from either side would be 2-1/2 feet and this constraint resulted in 48 radials at 7.5 degree spacing with the 100 foot deep stalls. Some historic literature indicates some stalls were extended beyond 100 feet but our photos failed to identify them, so we did not extend any. In 1914 there were four sections separated by masonry fire walls that extend beyond the roof. Running counter clockwise from the 1914 photo is 5 stalls with hip roofs + 10 + 10 + 10 with sloping roofs for a total of 35. We opted to build 5 + 7 + 7 + 7 for a total of 26. We continued to lay the remaining radial garden tracks around the circle, as it would be prior to covering them in the 1929 photo, so that we have an open area to display locomotives.
The modular table-work is a
blob at the end of a yard
so that we have access around three sides. It's located at the main
entry to the layout room for an impressive first glimpse (need photo link)
TURNTABLE: The home-made 100 foot turntable easily drops out underneath and is operational with an auto-seeking mechanism. Yet to be completed is the bridgework detail.
FRAMEWORK: How do you build a huge structure and make it sturdy
enough to survive possible future moves? The prototype had the earth to
tie it all together but we didn't want to tie it to the wooden tabletop
because who knows what we may want to do in the future, so we decided on
a sheet of galvanized steel sheet as a substrate with a framework of
1/8" square cold rolled steel
to represent the 12"x12" timber posts. It's all soldered together. The
code 83 MEI track is soldered to the sheet at the front and back of each
stall with double clad ties made from printed circuit (pc) board. By
slipping only 52 rail joiners, the entire structure can be removed and
handled as a unit.
ROOF: The roof will be
060 styrene in four lift-off sections
for access to the interior. A great deal of work will need to go into
the clerestories that were so essential for sunlight and ventilation.
.
FLOOR: We decided that excavating and modeling pits in the floor was the pits so there is no real need for concrete floors around pits. The current consensus of opinion is that floors of that era were likely just oily dirt. We are experimenting with pouring a dyed plaster floor to cover the sheet metal. We're getting some feedback from the LDSIG that suggest the floors were more likely wood plank. Even the "old-timers could not agree so it ended up kind of grundgy black.
WALLS AND WINDOWS: The walls like the roof are made of .060 styrene with a DIY brick paper. A scale brick mortor pattern was created with AutoCad and then imprinted on parchment paper procured from Kinko. The parchment paper provides a realistic texture of color to minimize the "flat-plastic" look without needing weathering efforts. This paper was laminated to the styrene. Windows are drafting mylar with the mullions printed on. Similiar construction was used for the clerestories, some of which have open windows for ventilation. The entire roof, in four sections, is easily lifted off for access.
LIGHTING: simple incandescent lighting was done with a pair of wire buss bars attached to the top roof beams. The small christmas tree bulbs are soldered to the buss wires, one in each stall. The lighting is soft, perhaps inadequate, suggesting a dingy work area. One of the primary reasons for the clerestories and big wall windows in these old buildings is to let sunlight in.
The techniques to build such a large HO scale structure obviously depart from the usual wood, plastic and glue used in smaller buildings. Hopefully, our experience will help some others contemplating something BIG.
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