When more than 3, an
auxiliary engine."
It will be seen that Mr. Randolph is well within bounds in ascribing to
the Mahanoy and Broad Mountain case (his No. 10) a date "certainly prior
to 1882," the date being given, in the notes, as 1864; while another
entry just below it, for the Pennsylvania Railroad case, is dated 1860.
It also seems, as stated by Mr. Randolph, quite probable that the
frictional resistance (6 lb. per 2,000 lb.) assumed by him in the
calculation is far below the actual for this Case 10. The small, empty,
four-wheel cars weighed only 4,400 lb. each. Furthermore, the "tons," in
the Trautwine reports of these experiments, were tons of 2,240 lb. On
the other hand, the maximum curvature was 12 deg. 45' (not 14 deg., as given by
the author), and the engine was a tank locomotive, whereas the author
has credited it with a 25-ton tender.
After making all corrections, it will be found that, in order to bring
the point, for this Case 10, up to the author's curve, instead of his 6
lb. per 2,000 lb., a frictional resistance of 66 lb. per 2,000 lb. would
be required, a resistance just equal to the gravity resistance on the
3.3% grade, making a total resistance of 132 lb. per 2,000 lb.
While this 66 lb. per ton is very high, it is perhaps not too high for
the known conditions, as above described.
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