TRUCK. ONE PAIR OF LEADING WHEELS, WITH SWING BOLSTER AND RADIUS-BAR, EQUALIZED WITH FRONT DRIVERS. Diameter of wheels 30 inches. WHEEL-BASE. Total wheel-base 21 ft. 10 inches. Rigid " (distance between rear and second pair of drivers) 9 ft. 10 inches. TENDER. ON TWO FOUR-WHEELED TRUCKS. Capacity of tank 2400 gallons. WEIGHT OF ENGINE IN WORKING ORDER. On drivers 87,000 pounds. On leading wheels 9,000 " ------ Total weight of engine, about 96,000 " LOAD. IN ADDITION TO ENGINE AND TENDER. On a level 2000 gross tons. " 20 ft. grade 990 " " " 40 " 635 " " " 60 " 460 " " " 80 " 355 " " " 100 " 285 " " ADDENDA. GENERAL DESIGN. The plan of this engine admits of either straight or wagon-top boiler, and of the use, with the proper form of grate, of either anthracite or bituminous coal or of wood. WHEEL-BASE. The arrangement of the wheels is such as to permit the engine to traverse curves with nearly as much facility as an engine of the ordinary type with only four drivers. The leading wheels having a swing bolster, and the front and main drivers having no flanges, the engine is guided on the rails by the leading wheels and by the flanges of the rear and second pairs of drivers. It is, therefore, impossible for the wheels to bind on the rails. Engines of this class are run around curves of 400 feet radius and less. TRACTIVE POWER. The distribution of the total weight of the engine gives about twenty-two thousand pounds for each pair of drivers,--a weight no greater than is carried on each pair of drivers of the larger sizes of ordinary eight-wheeled C engines. The single pair of leading wheels carries only nine thousand pounds. This arrangement renders available for adhesion a total weight of 87,000 pounds. One of these engines on a recent trial hauled one hundred and fifty gross tons of cars and load up a grade of one hundred and forty-five feet with sharp curves, and two hundred and sixty-eight gross tons of cars and load up a grade of one hundred and sixteen feet to the mile. The pressure in the first case was one hundred and ten pounds, and the speed six minutes to the mile; in the second case, the pressure was one hundred and twenty pounds, and the speed seven and one-half minutes to the mile.