Rotary snowplow
Encyclopedia
A rotary snowplow is a piece of railroad snowfighting equipment. It is characterized by the large circular set of blades on its front end that rotate as a unit to cut through the snow on the track ahead of it.

History

The rotary was invented by Toronto, Ontario, Canada dentist J.W. Elliot in 1869, however he never built a working model or prototype. Orange Jull of Orangeville, Ontario
Orangeville, Ontario
Orangeville is a town in south-central Ontario, Canada, and the seat of Dufferin County.-History:Before European settlers, Orangeville was thought to be a native hunting ground...

, expanded on Elliot's design, building working models he tested with sand. During the winter of 1883-1884, Jull contracted with the Leslie Brothers of Toronto to build a full-size prototype that proved successful. Jull later sold his design rights to Leslie Brothers, who formed the Rotary Steam Shovel Manufacturing Company in Paterson, New Jersey. Leslie Brothers contracted with Cooke Locomotive & Machine Works in Paterson to do the actual construction.

Operation

Wedge snowplow
Snowplow
A snowplow is a device intended for mounting on a vehicle, used for removing snow and ice from outdoor surfaces, typically those serving transportation purposes...

s were the traditional mechanized method of clearing snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...

 from railroad tracks
Rail tracks
The track on a railway or railroad, also known as the permanent way, is the structure consisting of the rails, fasteners, sleepers and ballast , plus the underlying subgrade...

. These pushed snow off the tracks, deflecting it to the side. Deeper drifts, however, cannot be easily cleared by this method; there is simply too much snow to be moved. For this purpose, the rotary snowplow was devised.

When a snowfall or snow drift becomes too deep, the railroads call on their rotary. The plow is not self-propelled, so one or more locomotive
Locomotive
A locomotive is a railway vehicle that provides the motive power for a train. The word originates from the Latin loco – "from a place", ablative of locus, "place" + Medieval Latin motivus, "causing motion", and is a shortened form of the term locomotive engine, first used in the early 19th...

s are coupled behind it to push the plow along the line. An engine within the plow's carbody rotates the large circular assembly at the front of the plow. The blades on this wheel cut through the snow and force it through a channel just behind the disk to an output chute located at the top of the blade assembly.

The chute can be adjusted to throw the snow to either the left or the right side of the tracks. An operator sits in a cab just above and behind the blade assembly to control the speed of the blades and the direction of output for the snow from the output chute. With the advent of dieselization, MU
Multiple-unit train control
Multiple-unit train control, sometimes abbreviated to multiple-unit or MU, is a method of simultaneously controlling all the traction equipment in a train from a single location, whether it is a Multiple unit comprising a number of self-powered passenger cars or a set of locomotives.A set of...

 controls have been added to the cabs, so that the pushing locomotives can also be controlled from the plow's cab.

In areas of particularly deep snowfall, such as California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

's Donner Pass
Donner Pass
Donner Pass is a mountain pass in the northern Sierra Nevada, located above Donner Lake about nine miles west of Truckee, California. It has a steep approach from the east and a gradual approach from the west....

, railroads sometimes would create a train consisting of a rotary snowplow at each end (with the blade ends pointing away from each other), and two or three locomotives coupled between them. With a plow on each end, the train would be able to get itself back to its starting location even if the snowfall was heavy enough to obscure the tracks it had just passed over. Such a train would also be able to efficiently clear multiple track mainlines as it could make a pass in one direction on one track and then reverse direction and clear the next track. This practice became standard for the Southern Pacific Railroad
Southern Pacific Railroad
The Southern Pacific Transportation Company , earlier Southern Pacific Railroad and Southern Pacific Company, and usually simply called the Southern Pacific or Espee, was an American railroad....

 on Donner Pass following the January 1952 stranding of the City of San Francisco
City of San Francisco
The City of San Francisco was a streamlined passenger train operated jointly by the Chicago and North Western Railway, the Southern Pacific Railroad, and the Union Pacific Railroad...

; during attempts to clear the avalanche
Avalanche
An avalanche is a sudden rapid flow of snow down a slope, occurring when either natural triggers or human activity causes a critical escalating transition from the slow equilibrium evolution of the snow pack. Typically occurring in mountainous terrain, an avalanche can mix air and water with the...

s that had trapped the train, two rotary plows were themselves trapped by further avalanches, and the crew of a third was killed when their plow was directly hit by an avalanche.

Rotary snowplows are highly expensive due to their high maintenance costs, which the owning railroad must pay regardless of whether they are needed in a given year. As a result, most railroads have eliminated their rotaries, preferring to use a variety of types of fixed-blade plows that have significantly lower maintenance costs, in conjunction with bulldozers, which can be used year-round on maintenance-of-way projects. In addition, because rotaries leave an open-cut in the snowbank that fixed-blade plows cannot push snow past, once rotaries have been used, they must be used for all further significant snowfalls until the snowbank has melted. Since rotaries, which need some form of fuel to power the blades, also cost more to operate than fixed-blade plows, they are now generally considered to be a "weapon of last resort" for the railroads that own them; they are only used when snow is too deep or heavy for fixed-blade plows.

The few remaining rotary plows are either owned by museum
Museum
A museum is an institution that cares for a collection of artifacts and other objects of scientific, artistic, cultural, or historical importance and makes them available for public viewing through exhibits that may be permanent or temporary. Most large museums are located in major cities...

 railroads, or are kept in reserve for areas with poor road access and routine severe snowfall conditions; the largest remaining fleet of rotaries consists of Union Pacific Railroad
Union Pacific Railroad
The Union Pacific Railroad , headquartered in Omaha, Nebraska, is the largest railroad network in the United States. James R. Young is president, CEO and Chairman....

's six ex-Southern Pacific plows reserved for Donner Pass.

Power

Early rotaries had steam engines inside their carbodies to power the blades; a few are still in working order, and in particular one on the White Pass & Yukon Route in Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 performs annual demonstration runs through thick snow for the benefit of photographers and enthusiasts
Railfan
A railfan or rail buff , railway enthusiast or railway buff , or trainspotter , is a person interested in a recreational capacity in rail transport...

. Newer constructed rotaries are either diesel or electric powered; in the latter case, an electric supply is required. Many steam plows were converted. Some electric plows can take their power from a locomotive, while others are semi-permanently coupled to power units, generally old locomotives with their traction motor
Traction motor
Traction motor refers to an electric motor providing the primary rotational torque of a machine, usually for conversion into linear motion ....

s removed; these are colloquially called "snails". (This is derived from the fact that engineless but motored units that take their power from another locomotive are "slugs
Slug (railroad)
A railroad slug is an accessory to a diesel-electric locomotive. It has trucks with traction motors but is unable to move about under its own power, as it does not contain a prime mover to produce electricity...

" - thus the opposite, with engine but no motors, is a "snail").

Preservation

Southern Pacific rotary snowplow MW208 is preserved in operational condition at the Western Pacific Railroad Museum
Western Pacific Railroad Museum
The Western Pacific Railroad Museum in Portola, California, formerly known as the Portola Railroad Museum before , is a heritage railroad that preserves and operates historic American railroad equipment. The museum's mission is to preserve the history of the Western Pacific Railroad and is...

 at Portola, California
Portola, California
Portola is the only incorporated city in Plumas County, California, United States. The population was 2,104 at the 2010 census, down from 2,227 at the 2000 census...

. This rotary was involved in the 1952 City of San Francisco
City of San Francisco
The City of San Francisco was a streamlined passenger train operated jointly by the Chicago and North Western Railway, the Southern Pacific Railroad, and the Union Pacific Railroad...

 rescue.

The Lake Superior Railroad Museum
Lake Superior Railroad Museum
The Lake Superior Railroad Museum is a railroad museum in Duluth, Minnesota.The museum has seven steam, fourteen diesel and two electric locomotives, and over 40 other pieces of rolling stock...

 in Duluth, Minnesota
Duluth, Minnesota
Duluth is a port city in the U.S. state of Minnesota and is the county seat of Saint Louis County. The fourth largest city in Minnesota, Duluth had a total population of 86,265 in the 2010 census. Duluth is also the second largest city that is located on Lake Superior after Thunder Bay, Ontario,...

 and the Museum of Transportation
Museum of Transportation
The Museum of Transportation of the St. Louis County, Missouri, United States Parks Department is a museum located in the Greater St. Louis area. It was first founded in 1944 by a group of individuals dedicated to preserving the past and has a wide variety of vehicles from American history...

 in St. Louis, Missouri
St. Louis, Missouri
St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...

 each have one on display.

The Northern Pacific Rotary 10 steam snowplow built in November, 1907 is currently owned by the Northwest Railway Museum
Northwest Railway Museum
The Northwest Railway Museum is a railroad museum in Snoqualmie, King County, Washington.-Snoqualmie Depot:The museum owns the Snoqualmie Depot built in 1890, of railroad right-of-way, and of the former Northern Pacific Railway North Bend branch...

 and is on display in Snoqualmie, Washington
Snoqualmie, Washington
Snoqualmie is a city next to Snoqualmie Falls in King County, Washington. The city is home to the Northwest Railway Museum. The population was of 10,670 at the 2010 census...

.

Rhaetian Railway still have one of their rotary snowplows in operating condition. It is mainly used on show runs for photographers, but when there's lots of snow it is still used to clear the Bernina line
Bernina Railway
The Bernina Railway is a single track metre gauge railway line forming part of the Rhaetian Railway . It links the spa resort of St. Moritz, in the Canton of Graubünden, Switzerland, with the town of Tirano, in the Province of Sondrio, Italy, via the Bernina Pass...

.


External links

  • The Rotary Snowplow - a Canadian Invention - quick overview with some historical photos.
  • Rotary snowplow list - lists rotary plows in existence, some of which are still in use today.
  • SP Rotary Snowplows - Many photos and details of rotaries that operate over Donner Pass
    Donner Pass
    Donner Pass is a mountain pass in the northern Sierra Nevada, located above Donner Lake about nine miles west of Truckee, California. It has a steep approach from the east and a gradual approach from the west....

     in California
    California
    California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

    .
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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