After reading the Dec. issues section about rotaries (which was very interesting by the way) I was only left with one question.
Were/Are any of the rotary snowplows able to move on their own power, and just need the extra loco's behind them for extra tractive effort and HP to move through the thick snow? Or were the engines in the rotaries devoted to the rotary fan and nothing else?
Also, was the engine directly connected to the rotary fan or did it power a generator which fed electrictity to a big electric motor that turned the fan?
Thanks!
Acela
The timbers beneath the rails are not the only ties that bind on the railroad. --Robert S. McGonigal
I am not aware of any 'self propelled' rotaries in North America. Most rotaries had the fan powered by s steam engine. The ywere later converted to a standard DC traction motor to spin the fan. They get their power from a trailing diesel electric. The UP has 1 or 2 rotaries that do have a diesel engine/generator suppling power to spin the fan, and do not need to get power from a trailing diesel electric. The diesel suppying power for the fan has it's traction motors cut out, and the power is routed to the rotary. Usually 2-3 diesel are pushing the rotary. They provide power to push it, and pull it out if it gets 'stuck'!
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
For North American rotaries, Jim has the right answer. The plow is not self propelled.
Japan had some Leslie-pattern rotaries, including a gasoline-powered four-wheel 'mini' that once ran on the 762mm (2'6") gauge Kubiki Tetsudo. None of them were self propelled.
More recently, the JNR and its privatized successors deployed specially-modified diesel-hydraulic locos fitted with the kind of auger-fed small-diameter snowthrower used by highway departments in the heavy snow regions of the United States. When not needed as snow removers, the plow assemblies could be dismounted. The locos then looked, and were used, like any diesel-hydraulic. Only the power takeoff shaft hatches gave them away.
Chuck
The Milwaukee had a couple of electric rotaries, where the power was taken directly off the catenary. Operating them was a bit tricky as they worked best when the line potential was dropped to less than 2,000V from the normal 3,000-3,300V.
- Erik
Various methods have been used to provide electrical power for rotary plows. SP and BN used de-motored F7B's numbered in a M/W series as power sources. BN/BNSF GP28P's 1590-1599 were equipped with power takeoffs from the main alternator which allowed them to serve as either slug or snowplow mothers.
There are some smaller self propelled rotaries in North America like this former Conrail machine now owned by CSX:
http://www.railpictures.net/viewphoto.php?id=186409&showexif=1
It's a newer machine of a different design than the Leslie rotaries. It is self propelled and operates without pusher locomotives.
IINM, all the Leslie type rotaries use electric traction motors to turn the blades, including the 2 newer Union Pacific units that have their own onboard prime movers.
I am under the impression that the 2 Bros Rotaries (1 owned by BNSF and 1 by Red River Western) use direct, mechanical drive from their on -board diesel engines to turn the impellers (they are very similiar to a household snowblower). The Bros plows still require locomotives to move them.
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
Question: in the December issue several of the rotary plows have what appears to be circular images in their windshields. I haven't seen any explanation for what these circles are. Anybody know?
Those circular devices are the windshield wipers.
Mike
erikem The Milwaukee had a couple of electric rotaries, where the power was taken directly off the catenary. Operating them was a bit tricky as they worked best when the line potential was dropped to less than 2,000V from the normal 3,000-3,300V. - Erik
Did those rotaries throw the snow plume upwards like the more conventional rotaries do? I would think there could be a significant danger from shorting out the catenary with the plume.
Levantine Question: in the December issue several of the rotary plows have what appears to be circular images in their windshields. I haven't seen any explanation for what these circles are. Anybody know?
Can't speak with certainty without checking the equipment of which you write, however many Canadian locomotives and ships of many nations have what are called clearvision windows. Within a larger window is mounted a motorized glass disk which spins to fling away anything wet. Some are also heated. More complicated but much more effective than the automotive style swish-swish wipers.
These are clear vision windows. You see them on ships. I did have a link to a company, but I'm sure if you google clear vision windows, you can get some excellent closeup pictures and descriptions. They prevent "freezing" up of the window allowing you to see through heavy rain or snow.
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