springing the former into the latter under pressure, it is possible
that a tire of larger diameter might be overstrained. But allowing
that the method of manufacture does not limit the diameter of a steel
wheel as it does a cast iron one, the claim that the larger diameter
is the best is open to debate at least, and, I believe, is proved to
the contrary on several accounts. It is argued that increasing the
diameter of a wheel increases its total mileage in proportion, or even
more. Whether this be so or not, there are two other very
objectionable features that come with an increase in diameter--the
wheel becomes more costly and weighs more, without giving in all cases
a proportionate return. We have to do more work in starting and
stopping, and in lifting the large wheel over the hills, and when the
diameter exceeds a certain figure we have to pay more per 1,000 miles
run. I am very firmly convinced that the matter of dead weight should
receive more attention than it does, with a view to reducing it. The
weight of six pairs of 42 in. wheels and axles alone is 15,000 to
16,000 lb.

The matter of brakes is coming up for more attention in these days of
high speed, heavy cars and crowded roads, and the total available
braking power, which has hitherto been but partially taken advantage
of, must be fully utilized. I refer to the fact that many of our
wheels in six-wheel trucks have gone unbraked where they should not.
As the height of cars and length of trucks cannot well be increased
for obvious reasons, it is necessary to keep the size of the wheels
within the limits that will enable us to get efficient brakes on all
of them that carry any weight. This is not easy with a 42 in. wheel in
a six-wheel truck, which is usually the kind that requires most
adjustment and repairs after long runs. The Pullman Co. has recognized
this fact, and is now replacing its 42 in. wheel with one 38 in. in