in the gross 350 tons, and to take this weight at a mean speed of
forty-five to fifty miles an hour over gradients of 1 in 264 is no light
work.

[Illustration: FIG. 6.--LONDON, BRIGHTON, AND SOUTH COAST RAILWAY.]

The engines known as the "Gladstone" type have inside cylinders 18¼ in.
diameter and 26 in. stroke, with coupled wheels 6 ft. 6 in. diameter under
the barrel of the boiler; the trailing wheels are 4 ft. 6 in. diameter,
and the total wheel base is 15 ft. 7 in. The frames are inside, of steel 1
in. thick, with inside bearings to all the axles. The cylinders are cast
in one piece 2 ft. 1 in. apart, but in order to get them so close together
the valves are placed below the cylinders, the leading axle coming between
the piston and slide valve. The boiler is of iron, 10 ft. 2 in. long, and
4 ft. 6 in. diameter; and the heating surface is, in the tubes, 1,373
square feet; fire-box, 112 square feet; total, 1,485 square feet. The
grate area is 20.65 square feet, and the tractive power per pound of mean
cylinder pressure is 111 lb. The weight in full working order is--leading
wheels, 13 tons 16 cwt.; driving wheels, 14 tons 10 cwt.; trailing wheels,
10 tons 8 cwt.; total, 38 tons 14 cwt. The tender weighs 27 tons.

To enable these engines to traverse curves easily a special arrangement of
draw-bar is used, consisting of a T-piece with a wheel at each end working
in a curved path in the back of the frame under the foot plate; on the
back buffer beam a curved plate abuts against a rubbing piece on the
tender, through which the draw-bar is passed and screwed up against an
India-rubber washer, thus allowing the engine to move free of the tender
as the curvature of the road road requires; the flanges on the driving
wheel are also cut away, so as not to touch the rail. In order to reduce
the wear of the leading flanges, a jet of steam from the exhaust is