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Someone explain grain elevators to me
How are the elevator and/or tanks used?
QUESTION:Some questions from a naieve modeler trying to understand the hobby
terminology better:
1. Is there something in prototypes/model railroading known as a
"switchback"? If so, what is it?
2. What exactly is the purpose and function of a signal tower, as in
the Campbell structure one can buy as a kit. Or interlocking tower,
for the matter? Where do I place these structures on a model railroad,
and why?
3. Someone explain grain elevators to me. Seems they raise the grain up into
these big tanks..then what? Is that all there is to it? How are the
elevator and/or tanks used? Where do I put them on a model railroad?
4. Water towers. One of those 'why is the sky blue' type questions Ive
always wondered about. How do they get the water in the thing?
What other structures should I put near one for prototypical accuracy?
5. extra credit. Purpose, function and prototypical location of a sandhouse?
Was the sand used to help the wheels grip for Steam locos? How does the
sand get into the engine? another structure/tower?
ANSWER: Q: Is there something in prototypes/model railroading known as a
"switchback"? If so, what is it?
A: Where a track ascends a grade by a series of turnouts, as in:
top lower
---------------------------------------------
/
-----------
yet lower / bottom
----------------------------------------------
Q: 2. What exactly is the purpose and function of a signal tower, as in
the Campbell structure one can buy as a kit. Or interlocking tower,
for the matter? Where do I place these structures on a model railroad,
and why?
A: Place such a structure near a junction with a clear view of the tracks
involved. Small towers would typically have perhaps 4 levers, controlling
three signals and one turnout. Larger towers would be needed to control
more complex trackage and signals. Levers in the tower would (back 100
yuears ago) be connected directly to push rods that ran from the base of
the tower and parallel to the tracks to the signals or turnouts. Where
rods turn corners, there'd be a crank, and other cranks would equalize
for the effect of thermal expansion and contraction.
Q: 3. Someone explain grain elevators to me. Seems they raise the grain up into
these big tanks..then what? Is that all there is to it? How are the
elevator and/or tanks used? Where do I put them on a model railroad?
A: An elevator just raises the grain. Grain mills and grain storage locations
will have at least one elevator. What we typically call a grain elevator
is really a grain storage depot. The elevator lifts grain, from any of
a number of sources, and disperses it at the top, through an output manifold,
to any of a number of destinations. There may be augers to bring grain to
the base of the elevator (usually through underground hallways under the
structure) and there may be augers to distribute the grain horizontally
from the top of the elevator. Generally, though, gravity moves the grain
to the base of the elevator and from the top to the destination.
An auger looks like a pipe (perhaps a foot in diameter) with a motor at
one end. The motor drives a screw inside the pipe that pushes the grain
horizontally or up a gentle upgrade.
In a grain storage depot, trucks or railcars deliver grain, where it is
lifted from the unloading pit by an elevator, and then shifted to one
or another of the vertical holding silos, usually made of cement these
days, but historically made of timber. Different grades or types of
grain may be stored in each silo. During the fall harvest, regional
elevators buy grain from farmers and hold it until the price is right,
and then they ship it, typically in unit grain trains, to customers.
At intermodal terminals, for example, along the Mississippi or at Duluth
or New Orleans, entire unit trains of grain are unloaded into dockside
elevators that then load into ships or strings of barges. In New Orleans,
they unload strings of barges into dockside elevators that can load into
ships.
Finally, the milling locations, places like Quaker Oats in Cedar Rapids,
General Mills in Minneapolis, or Kelloggs in Battle Creek, have elevators
that can accept trainloads of grain when the price is low and then hold
it until it is needed for making cerial.
Feedgrain is also shipped by rail to feedmills that have their own elevators
to hold both raw grain and the blended and processed animal feed. Feed
is then shipped by rail or truck to feed distributors, typically with
smaller elevators, and finally the feed is trucked to farms.
On-farm storage of grain and feed involves metal grain bins and either
portable grain augers or small elevators for moving the grain around between
grain wagons, bins, and trucks.
Q: 4. Water towers. One of those 'why is the sky blue' type questions Ive
always wondered about. How do they get the water in the thing?
What other structures should I put near one for prototypical accuracy?
A: Somewhere near the water tower, you typically need either a reservoir or a
well. Then, with wells or reservoirs below tower level, you need a pump
house. Sometimes, the tower is built directly over the well, with the
pump house built directly under the tower. Other times, the reservoir and
pump house may be out of sight, perhaps as far as a mile away, but usually
less. Modern (post 1920's) pump systems are electric. Early pump houses
(pre 1950's) tended to use steam powered pumps, so there'd be a small coal
pile nearby, and once in a while, a local section hand would have to stop
by and stoke the fire to keep the little pony engine running.
Q: 5. extra credit. Purpose, function and prototypical location of a sandhouse?
Was the sand used to help the wheels grip for Steam locos? How does the
sand get into the engine? another structure/tower?
A: Whether steam or diesel, from the 100 years ago or today, locomotives carry
sand to help with traction when the rails are wet or icy. Typically, theres
a sandbox somewhere in the engine, with diagonal pipes from the sandbox
to some of the driving wheels, and when the engineer senses that the wheels
are slipping unexpectedly, he feeds some sand by blowing it through the
pipes with compressed air, or, in early systems, by gravity feed.
In any case, the sand used in an engine has to be dry, so it won't cake up
in the sand box and fail to flow to the wheels where it's needed. As a
result, sandhouses typically cook their sand dry before loading it in a
sand silo to be held until needed. Sand is moved around the sandhouse
by gravity, when possible, an elevator (as in grain) is typically used to
lift sand from the bottom of the wet sand holding pile into the drying
oven, and then either an elevator or compressed air are used to blow dry
sand from the oven into the holding silo. The holding silo is typically
up high enough to allow gravity loading into engines. Small engine service
facilities, even today, use far less automation in their sand handling.
On short lines, even today, loading sand by hand using buckets is still
done.
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