atent 27850, issued April
10, 1860.]

Levi Bissell produced the basic patent for such a truck in 1857. Zerah
Colburn in September of that year had suggested to Bissell that he
develop a 2-wheel truck. Such a device, he believed, would be well
received in Britain.[18] He was quite correct, as will shortly be seen.

In nearly every respect Bissell's 2-wheel truck (see fig. 7) followed
the idea of the original patent for the 4-wheel truck, which he claimed
as the basis for the present invention. The pintle was located behind
the truck axle, near the front driving-wheel axle, and the weight was
carried by incline planes that also served as the centering device.

A study of the patent drawing in figure 7 reveals several interesting
points. Note that the V's, and thus the point of bearing, are slightly
in front of the center line of the truck axle. It was suggested in the
patent specification that the V's might be placed to the front, rear, or
directly over the axle, but in most actual applications they were placed
directly over the axle. Note also that the locomotive shown on the
figure is obviously a standard high-wheel American type which has
suffered the rather awkward substitution of a pony truck for its regular
4-wheel arrangement. It is probable that few if any American types were
so rebuilt.

Bissell was granted U.S. patent 21936 on November 2, 1858. British
patent 2751 was issued for the same device on December 1, 1858. A few
months later, in the summer of 1859, service tests of Bissell's new truck
began in England.

First known use of the truck was on the British Eastern Counties Railway
_No. 248_, a rigid-frame 2-4-0 built by Kitson in 1855. The leading
wheels of the engine, as originally constructed, were attached to the
frame in the same manner as the drivers and thus had no lateral
freedom. For the test the front pedestals, which held the journal boxes
of the leading wheels, were cut off and a Bissell pony truck was
substituted. About a year later Alexander L. Holley reported on the
success of the test.[19] The 248 had operated 17,500 miles, at speeds up
to 50 m.p.h., safely and satisfactorily. The engine not only rode more
steadily but showed a remarkable reduction in flange wear. The road was
so pleased that by 1866 they had equipped 21 locomotives with Bissell
trucks.[20] Several other British lines followed the example of the
Eastern Counties Railway.

[Illustration: FIGURE 10.--The Hudson-Bissell tru