axle-boxes and long bogie coaches, irrespective of other improvements,
would render this course desirable. With regard to the former, they appear
to run with less friction, but are heavier to start, oil boxes in some
experiments made on the South-Western Railway giving a resistance of 2.5
lb. per ton, while grease boxes ranged from 6 lb. to 9 lb. per ton. Again,
the long and heavy bogie Pullman and other coaches have the reputation
among drivers, rightly or wrongly, of being hard to pull. The resistance
of an express train on the Great Western Railway at seventy-five miles an
hour was 42 lb. per ton, and taking 40 lb. per ton for seventy miles an
hour would give a total resistance on the level of 7,000 lb.,
corresponding to 1,400 horse-power--about double the average duty of an
express engine of the present day. The weight on the driving wheels
required would be 18¾ tons, allowing one-sixth for adhesion, about the
same as that on the driving axle of the Bristol and Exeter old bogie
engines. Allowing 2½ lb. of coal per horse-power per hour would give a
total combustion of 3,500 lb. per hour and to burn this even at the
maximum economic rate of 85 lb. per square foot of grate per hour would
require a grate area of 41 square feet, and about 2,800 square feet of
heating surface. Unless a most exceptional construction combined with
small wheels is adopted, it appears almost impossible to get this amount
on the ordinary gauge. It is true the Wootten locomotives on the
Philadelphia and Reading Railway have fire-boxes with a grate area of as
much as 76 square feet, but these boxes extend clean over the wheels, and
the heating surface in the tubes is only 982 square feet; but although
these engines run at a speed of forty-two miles an hour, they are hardly
the type to be adopted for such a service as is being considered. On the
broad gauge, however, such an engine could easily be designed on the lines
now recognized as being essential for express engines without introducing
any exceptional construction, and there appears but little doubt that were
Brunei's magnificent gauge the national one, competition would have