N&W in 1910--Leviathans
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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 first of three related articles on that page to be presented individually.]
PRACTICALLY THE SAME AS TWO LOCOMOTIVES
The American Company's New Articulated Compound Mallet Furnished The N. & W.
Some exceptionally heavy and powerful locomotives for freight service have recently been added to the equipment of the Norfolk and Western Railroad [sic] Company. These are of the type known as the articulated compound, and are more than twice as powerful as the largest freight engine now in service on that road.
This type of locomotive represents one of the latest and most important developments in locomotive practice in this country within the past decade. It was first developed by a prominent French engineer, M. Anatole Mallet for freight service on roads having steep grades and sharp curves. To the American Locomotive Company, who quickly realized the adaptability of this type to American railroad conditions, belongs the credit for the introduction of the articulated compound locomotive into this country. In 1904 these builders constructed an engine of this type for freight service on the Baltimore and Ohio Railroad, which was the first of its class ever built in the United States.
In the six years then, the articulated compound locomotive has come into great prominence, and is fast becoming the most popular type of heavy freight engine, particularly on those roads where the requirements have outgrown the capacity of locomotives of the more ordinary type.
The engine here illustrated, which is one of the five built by the American Locomotive Company for the Norfolk and Western Railroad [sic], is one of the most powerful locomotives ever constructed. This lot of freight engines will be used on some of the heavy grades on this road, of which there are quite a number. They will probably be put into service on the Elkhorn grade, which is a rise of 105.6 feet per mile [2 percent], and the steepest one on the line.
At the present time, the heaviest class of freight power is a twelve-wheel engine having a tractive power of 40,160 pounds, weight on driving wheels of 168,000 pounds and a total weight of 168,000 lbs. [sic., Class M total engine weight is 206,200 lbs. in Jeffries' book.] This class of engine will handle only 600 tons on the Elkhorn grade. With the introduction of the articulated locomotives the railroad company will have a class of power capable of handling over twice that tonnage. This order was directly due to the satisfactory performance of engines of similar type built by these same builders for the Virginian Railway, the success of which led the Norfolk and Western Railroad [sic] officials to adopt the articulated type for their road.
This engine is practically two locomotives combined in one. It has sixteen drive wheels arranged in two groups of eight each. The rear group of wheels is carried in frames which are rigidly attached to the boiler, while the forward group of wheels is carried in frames which are not so attached, but are joined to the rear frames by hinged connections. The front group are thus in fact a truck which is capable of swiveling radially about the pivot connection with the rear group. This arrangement gives a locomotive capable of passing through curves of short radius, and at the same time having an enormous weight and corresponding hauling power. The weight being distributed over so many driving wheels, this monstrous engine is no harder on track and bridges than an engine of the ordinary type of one-half the weight and power.
The high pressure cylinders which are seen in about the center of the engine, and are 2 1-2 [sic, 24-1/2 in Jeffries' book] inches in diameter, drive the rear group of wheels and the low pressure cylinders, which are 3 feet, 3 inches in diameter and 2 feet, 6 inches in stroke, drive the forward group of wheels.
After passing through the high pressure cylinder the steam exhausts into what is called a receiver pipe from whence it is led to the low pressure cylinders where it performs additional work. The pipe connections between the high pressure and low pressure cylinders and the low pressure cylinders and the boiler are made with flexible joints so as to provide for the swinging of the front group when the engine is rounding a curve.
By an ingenious hydro-pneumatic severing mechanism, the invention of its builders, the reversing of this enormous engine is rendered easier than that of an ordinary locomotive. In working order the engine has a total weight not including tender of 375,000 lbs. The weight of the engine and tender together is 544,300 lbs. [Blurred on microfilm. The value in Jeffries' book is shown.] To supply the boiler with water for the trip it requires a tank having a capacity of 9,000 gallons.
Ordinarily, the engine has a tractive power of 85,000 lbs. [sic., tractive effort compound is 66,892 lbs., simple is 83,615 lbs. in Jeffries' book]. With the builders' system of compounding this power can be increased 20 per cent by changing the engine into single expansion. This is done by means of what is called an intercepting valve, which is a feature peculiar to engines of this type built by the American Locomotive Company and also governs the pressure of the steam in the receiver pipes. All the operations of this valve are automatic, except that which changes the engine into single expansion. This latter operation is accomplished by merely turning a valve in the engineer's cab, which permits the steam which passed through the high pressure cylinders to escape to the atmosphere, and admits the steam direct from the boiler to all four cylinders, giving the increase in power above mentioned.
The boiler measures 78 inches in diameter outside at the front end, and its largest diameter is 81 1-4 inches. It is fitted with 334 tubes 24 inches [sic] long, giving a heating surface of 4,705 sq. feet. There are 200 square feet of heating surface in the fire-box, making the total heating surface of the boiler 4,905 square feet. The fire-box is ten feet long and 7 feet 1-4 inches wide, and has a grate area of 70.2 square feet.
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