Green-Mountain freeman. [volume] (Montpelier, Vt.) 1844-1884, 1850-12-05
Fast Travelling on Railroads.

| correspondent wishes TO know why the
speed ofrailroad travelling in this country is not
increased as in England He states that the
average Of speed hare is but fifteen miles an
hour, while in Grept Britain it is not less than
'orty' we think he is somewhat mstnken'-
The average speed in the United States is Ger.
talny twenty miles an hour, while in Enpland
1t is not over twenty-five. He has coniounded
the Express trains with the ordinary trains. or
ne would not have set down the speed of the
British railroads at forty miles. Some Of the
trial trains here run at velocity Of seventy
miles an hour but this is by no means com.
mon occurrence, the ordinary speed by these
trains being generally about thirty miles per
hour.
The principle railroad in the United States
run their passenger trains as fast as those Of
England are run, and il is only on roads of sec.
ondary Importance that ,he British trains have
the advantage over ours. The speed of the first
class cars on the London and Liverpool road, is
twenty five miles, including stoppages on the
London and Southampton it is twenty four ms.
including stoppages. The velocity of the even
ing trains between here and New York is about
twenty two miles, including stoppages on the
Erie railroad it is between twenty-five and thlr-
ty; and on the Great Western, between Albany
and Boston, it is very nearly as great Occa.
sionally trains have been run on nearly all these
| 10 at n Vnl thon
express trains in England and on tria! trips,
speed has been attained nearly if not quite, as
great as on the British roads, That higher
velocity is not ordinarily employed, ls owing to
the increased danger of accidents, and to the
rapid ratio at which the wear and tear of the
road progresses under the accelerated speed.
We can best illustrate this augmented wear
and tear by endeavoring to obtain definite idea
of what the speed of seventy miles per hour
means.
Seventy miles an hour is one hundred and five
feet every second, that s the passenger is carri-
ed hrty-fve yards between the beats of COM
mon clock: When two trains having this veloc-
ity pass each other, the relative speed would be
doubled =; and if one of the trains were seventy
yards long, it would fash by in single second
Ifthe driving wheel Of the locomotive is seven
feet in diameter, the wheel would revolve five
times in passing over the thirty five yards, con.
sequently FIVE times every second To produce
q single revolution of the wheel, the piston rod
must move backwards and forwards once hence
its motion will divide every second into ten G.
quail parts The valve must, in like manner
move ten times every secoud and as steam es-
capes at every opening of the valve, there must
be ten snch escapes every second, But loco
motive has two cylinders and the discharge from
one is intermediate between two successive dis
charges from the other consequently there twen-
ty discharges of steamn second each puffhav
ng the twentieth of a second between il and
that which proceeds or follows it. Passengers
have heard these discharges when the Iocomo.
tive is moving slowly at starting, and will recog-
nize them by their sounding like quick cough,
or gasp. Some idea of the enormous rapdity Of
the working parts of the engine may be obtained
by remembering that at speed OF seventy miles
hat there are twenty of those coughs per Sec
ond.
Nor is this all Though the driving wheels
of large locomotives are seven feet in diameter,
the bearing wheels are not more than three
But driving wheel revolves when at a speed of
seventy miles, five times each second hence the
bearing wheels must revolve twelve miles. A
cannon ball, it has been computed, moves at u
rate of 26,600 feet per minute, which is equal to
300 miles per hour. A train therefore, might at
IS miles an hour, speed frequently obtained by
trial locomotives for short distance. has ve-
locity only four times less than caurJu ball.
} In stopping such trains the difficulty is much