As we
look at the scoop wheel from the front
of the plow, you can imagine that a counter-clockwise rotation would throw
the snow to the left. A clockwise rotation would empty the snow cones to the
right right side of the wheel as we look at it.
Below, a rotary is approaching the camera. The plume of thrown snow is dwarfed
by the smoke and condensing exhaust steam of the plow and the locomotive(s) behind it.
The rotary pilot in the cab of the plow would be watching the snow load
to be moved ahead of the train and listening to the chuffing exhaust of his
rotary and other telltale sounds. He would signal the locomotive to slow if the wheel was in danger
of stalling, or to speed up if the rotary could be worked more efficiently.
All that fluffy steam comes from water - in this type of slow heavy work rotaries and
locomotives used large amounts of water. In extreme cases, heavy wet snow mixed with falling rain ensured
very slow progress. But it was still better than shovelling by hand !
If the orange plow was used here in the location pictured below, it would be making a useless effort to
push the snow up hill. These photographs are not from Newfoundland.
Below, you can see what the rotary left behind. If the snow was too far
over the top of the plow's scoop wheel, it was advisable to shovel the excess off by hand
before running the rotary into it. You can see that deeper flanger grooves
have been carved on the insides of the rails for the wheel flanges to protect against ice buildup and derailments.
In Newfoundland (and elsewhere), it was often advantageous to have a rotary
train with the locomotive
s in the middle and a rotary snowplow facing outward
on both ends. This operating detail suggests that they had some major problems with snow around
the Topsails and the last thing they wanted was to get a single rotary stuck
in the snow with no "backup" plan. It also eliminated the need to turn a single rotary to run back
through a heavy snowstorm or deep drifting ...
Checking the 1957 timetable above, there were 6 places to turn trains in
the 90 mile section which included the Topsails. They are indicated by the
symbol "Y" which crudely represents the path a train would follow to turn
around.
There is an explanation on how "wyes" work on the "Heron Bay Subdivision"
page under the section on "Struthers".
To turn a train on a wye in a snowstorm, three switches would have to be
located, dug out, and thoroughly cleaned out by hand.
As
single snowplows and
single rotary snowplows could only be useful in one
direction, having multiple places to turn was handy. It enabled plows to
make repeated passes where the snowfall or drifting was the heaviest. It
also made relief quicker when regular trains became stuck and needed to be
rescued as soon as possible. Passenger trains sometimes got stuck for
days in Newfoundland.
If you haven't before, why don't you take a peek inside a steam-driven rotary
snowplow ...
Before large diesel, and diesel-electric powerplants were available to spin
the big scoop wheel, designers in the late 1800s and early 1900s used steam
power.
The rotary snowplow is propelled forward by a regular locomotive,
so the square firebox and the round boiler extending out to its right are
there
specifically to drive the scoop wheel. The plow could never propel itself.
Pipes coming down on both sides of the boiler from the barrel-like steam dome (at the
top) carry steam to the cylinders where the steam's expansive power alternately pushes
on one of the two pistons - one on each side. Because the fuel is burned outside the
piston, this is an
external combustion engine.
In the little
box above the piston are valves which control the flow of the expanding gas(es) in and out of the cylinder like an automobile's
engine valves do. Located between the little box above the cylinder and the scoop wheel, are all the linkages
which essentially control the direction, speed and power of the scoop wheel.
You can also see the driveshafts responsible for converting the reciprocating
motion of the piston, to transverse rotation, to longitudinal rotation ...
or as I would say it: in and out ... becomes round and round across
to the centre of the plow ... becomes round and round forward to the centre
of the scoop wheel ... which spins like a big pinwheel.
From reading accounts of rotary operation it seems that the main drive shaft was weakened to break before major damage
was done to other mechanisms. Working around Gaff Topsail, they had an efficient
routine for changing out a broken drive shaft in the middle of a snow storm.
Let's face it, they HAD to be good at this - it was a pretty tough neighbourhood to be stranded in.
And behind the second wheel of the plow, you can see a big healthy flanger
(the scoopy-looking thing) which would be raised and lowered by air or steam
pressure. The lowered flanger would scoop the snow away from inside the rail
and plow it over the rail and off to the outside of the track structure where it couldn't bother anyone ever again.