of Munich. As will be seen from our illustrations, the engine has
outside cylinders, these being 20.48 in. in diameter, with 24 in.
stroke, and as the diameter of the coupled wheels is 3 ft. 10 in.,
the tractive force which the engine is capable of exerting amounts to
(20.48 squared x 24) / 46 = 218.4 lb. for each pound of effective pressure per
square inch on the pistons. This is an enormous tractive force, as it
would require but a mean effective pressure of 1021/2 lb. per square inch
on the pistons to exert a pull of 10 tons. Inasmuch, however, as the
engine weighs 44 tons empty and 51 tons in working order, and as all
this weight is available for adhesion, this great cylinder power can be
utilized. The cylinders are 6 ft. 10 in. apart from center to center,
and they are well secured to the frames, as shown in Fig. 4. The frames
are deep and heavy, being 1 3/8 in. thick, and they are stayed by a
substantial box framing at the smokebox end, by a cast-iron footplate at
the rear end, and by the intermediate plate stays shown. The axle box
guides are all fitted with adjusting wedges. The axle bearings are all
alike, all being 7.87 in. in diameter by 9.45 in. long. The axles are
spaced at equal distances of 4 ft. 3.1 in. apart, the total wheel base
being thus 12 ft. 9.3 in. In the case of the 1st, 2d, and 3d axles, the
springs are arranged above the axle boxes in the ordinary way, those of
the 2d and 3d axles being coupled by compensating beams. In the case of
the trailing axle, however, a special arrangement is adopted. Thus, as
will be seen on reference to the longitudinal section and plan (Figs. 1
and 2, first page), each trailing axle box receives its load through the
horizontal arm of a strong bell-crank lever, the vertical arm of which
extends downward and has its lower end coupled to the adjoining end of a
strong transverse spring which is pivoted to a pair of transverse stays
extending from frame to frame below the ash pan. This arrangement
enables the spring for the trailing axle to be kept clear of the
firebox, thus allowing the latter to extend the full width between the