National Republican. (Washington City (D.C.)) 1872-1888, 1879-10-18
The DynaGraph-An Ingenious Machine.

At the present time our mos, progressive rail-
road managers are anXiously seeking for inn
provemens in all and any direction that will
enable them to perform their duties to their
stockholders and the public in the most salts
factory manner. In times past there has been
too much of the hap-hazard way of managing
our ironways, but thanks TO the present
keenness decomposition, that style Of running
railroads II giving way to better methods.
One of tho most important subjects upon
which IL is desirable for railroad managers to
be informed Is that of the resistance of rail-
road trains. To ascertain this, the dynamom-
eter, or spring.balance, has been used but with
unsatisfactory results from the fact that only
the tension upon the draw.bar is given. What
has been wanted was an automatic register
ing machine that should give a complete
record of tho various phenomena connected
with u train when in motion upon the rails
This desirable result appears to have been ar
rived at in Mr.. Z, IL. Dudley's dynagraph, "a
machine with no less than fourteen record
ing pens which make diagrams of the phe.
nomena concerned in drawing a train.
Mr.. Dudley is now engaged in conducting
some interesting experiments upon the Bos-
ton & Albany railroad with his dynagraph,
which is a very complicated machine, occupy
ing "A space three or four feet square in Il car
constructed especially for the purpose, and
contains besides the dynagraph, excellent nc.
commentators LOT lIt luNeulOI anu MS Wllct
who accompanies him, aud is an excellent rs.
sstant rs well as housewife. In the car
room is also found for piano, library, lab.
oratory, sc. The draw-bar of the car is con-
nected with piston, which works in cylin-
der under the floor, and which is filled with
oil. These are so arranged that II the draw
bar is subjected TO strains Of either tension
or compression they are resisted by the oil in
the cylinder. From this cylinder there runs
small pipe, which connects with n small
cylinder placed on the top Of tho machine
This has piston in IL which connects by II
rod and carries pen which draws u diagram
of the resistance OF the train upon roll of
paper some Thirty inches In width. This
paper is fed over a table ut tho top of the ma
chine by very ingenious cOntrivanCe. As
the paper rolls across the table stationary
pen marks what is called base line. This
line is followed by the pen mentioned above
when there is no tension upon the draw-bar,
but AS soon as there is any pressure in the
draw.bar cylinder the pen is carried away
from the base line distance proportional TO
the pressure, and tho diagram Immediately
indicates the tension ON the draw-bar.
The speed OF the trains is recorded by means
of an electric attachment, with II chrOnometer
clock upon tho machine, which indicates tho
space Travelled over each second. The next
pencil is arranged to mark the distance tray
elOd every ten seconds, and still another pen
is used to record minutes. A pen is also ar
ranged so that by an electrical connection IL
records each revolution Of the driving wheels.
! Another records the mile'posts as they are