N&W in 1910--Leviathans, Part 2

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Bluefield Daily Telegraph
June 5, 1910

[A side view photo of 0-8-8-0 engine No. 990 extended across the full width of Page 7 at the top with the caption, "The New Leviathans That Will Haul the Great Output of the Pocahontas Coal Fields from Mine to Market--the Mallet Engine and What it Does."  The following article is the second of three related articles on that page to be presented individually.]

THE MALLET ENGINE
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Description of The Monster Made by The Baldwin Locomotive Works
    The Norfolk & Western Railway has recently received from the Baldwin Locomotive Works five locomotives for heavy freight service on mountain grades [Class Y1, 2-8-8-2, N&W 995-999].  These engines belong to what is known, from the name of its inventor, as the mallet type.  Each is carried on twenty wheels, and is equivalent to two locomotives of the ordinary type.  The driving-wheels are divided into two groups of eight wheels each, and in addition there is a two-wheeled swing truck at each end to assist in guiding the engine around curves.  Each group of driving wheels is held in a separate frame and is rotated by a separate pair of cylinders.  The front frames are hinged to the rear frames, so that the front group of driving wheels acts like a truck and the engine can traverse sharp curves with ease.  The cylinders are arranged on the compound system.  That is, the steam is first used in the rear, or high pressure cylinders, and then in the front or low pressure cylinders.  This method of using steam results in considerable economy in fuel and water.
    The Norfolk & Western engines are so constructed that they can be easily separated into two sections.  This facilitates handling the locomotives in the shop when making repairs.  The front section of the boiler is fitted with a chamber in which the feed-water is heated before being forced into the boiler proper.
    The principal dimensions of the Norfolk & Western locomotives are as follows:
    Cylinders, 24 1-2 and 38 x 30 inches.
    Driving wheels, diameter, 56 inches.
    Steam pressure, 200 pounds per square inch.
    Total heating surface, 5905 square feet.
    Grate area, 75.2 square feet.
    Weight on driving-wheels, 360,000 pounds.
    Weight of engine, total, 390,000 pounds.
    Total weight of engine an tender, 540,000 pounds.
    Water capacity of tender, 9000 gallons.
    Coal capacity of tender, 14 tons.
    Locomotives of the mallet type can frequently be used to advantage in special service, on lines having heavy grades and sharp curves.  This is especially true of logging service.  A mallet locomotive with two or three pairs of driving wheels in each group, can be designed to haul heavy loads, and at the same time have a moderate amount of weight per wheel and so be easy on the track.  Such a locomotive can traverse sharp curves with ease, while it avoids the use of a complicated form of driving mechanism such as is found in geared locomotives.  The Baldwin Locomotive Works have built a number of mallet engines for logging roads, and more are under construction for this kind of service.  The works will be pleased to furnish further information to interested parties.
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[The principal dimensions given in the article are not significantly different from those in Jeffries' book on N&W steam except the diameter of the low pressure cylinders, which should be 39 inches instead of the 38 inches given in the article.]

Gordon Hamilton
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