resistance to traction.

"The engine had four coupled wheels and a bogie, the total weight in
working trim being 291/2 tuns, of which 17-7/8 tuns rested on the coupled
wheels available for adhesion. The coupled wheels were 5 feet in
diameter; the outside cylinders were 17 inches in diameter, and the
stroke 24 inches. The safety valves were set to blow off at 130 lbs.,
and the steam, as observed by a Bourdon gage, was seldom allowed to
exceed that limit. No indicator diagrams were taken, nor was any measure
taken of the wood burnt, all that could be consumed by the engine, in
maintaining the requisite steam, being supplied. The tender, loaded,
weighed 181 tuns. The train drawn consisted of eight-wheel wagons fully
loaded with deals. The average weight of each wagon was 5 tuns 8 cwt. 3
qrs., and of each wagon with its load 15 tuns 5 cwt. 3 qrs. nearly. The
wagons had cast-iron chilled wheels, each 2 feet 6 inches in diameter,
with inside journals 3 7/8 inches in diameter, and 8 inches long. All
the wagons had been put in complete order, and the journals, fitted with
oil-tight boxes, were kept well oiled. The gage of the line was 6 feet.
The weather was most favorable, clear and dry, with the exception of a
single day of heavy rain.

"Upon about one hundred miles of the line, forming a portion of the
Susquehanna division, a train of one hundred wagons, weighing, with
engine and tender, 1,572 tuns was taken. The train was a few feet more
than half a mile in length.

"At one point it was stopped where the line commenced an ascent of 24
feet in four miles, averaging 1 in 880 up for the whole distance. There
were also long and easy curves upon this portion. The train was taken up
and purposely stopped on the second mile, to be sure of starting again