Table 2 (in which the writer follows the author in assuming frictional
resistance at 4.7 lb. per 2,000 lb.) shows the cases giving the maximum
and minimum values of the quantity represented by the ordinates in the
author's diagram, namely, "Traction, in percentage of weight on
drivers."

It will be seen that the maximum percentage (16.1) is practically
identical with that found by the author (16) for grade lengths exceeding
17 miles.

Near the middle of the 34-mile distance there is a stretch of 1.51
miles, on which the average grade is only 5.93 ft. per mile (0.112%),
and this stretch divides the remaining distance into two practically
continuous grades, 19.39 and 13.13 miles long, respectively; but, as the
same loads are hauled over these two portions by the same engines, the
results are virtually identical, the maxima furnishing two more points
closely coinciding with the author's diagram.


TABLE 2.--TRACTIVE FORCE, CATAWISSA TO LOFTY.

========================================================================
Length of grade, in miles | | 34.03
| |
Grade {in feet per mile | | 31.47
{percentage |_A_ | 0.597
| |
Resistances, in pounds per 2,000 lb., | |
Gravity (=20 _A_) = 11.94. Friction = 4.70 |_B_ | 16.64
| |