The Topeka state journal. [volume] (Topeka, Kansas) 1892-1980, 1910-01-03
Passenger Locomotives Cannot
Run Any Faster.
Seventy-Five Miles an Hour Is
High Speed Average.
LIMIT 100 MILES HOUR
Mechanism and Track Keep
Down Higher Speeds.
Other Items of General Interest
in Railroad Circles.

It has been surprise and dlsap-
pointment to many motive power offl-
GERS that their best efforts in build
ing locomotives for fast speed express
service have not produced an engine
which will haul a train of five or six
modern cars at speeds much above 6O
miles an hour, and at so and 80 miles
an hour the largest engines with boil
ers having heating surface OF 3,oOV
to 1000 square feet are scarcely able
to propeI themselves, says the Rail-
road Age Gazette.
The principal limitation of the
steam locomotive at high speed is IN
the horsepower of the cylinders rather
than the boiler. The efficiency OF the
heating surface in locomotive boilers
is such that one-half horsepower
should be expected per square root OF
heating surface, and 1000 square rect
would equal 1000 horsepower, or an
equivalent tractive effort at 100 miles
per hour of $500 pounds.
The principal resistance at this
speed is from air pressure at the front
end.
With the present standard design
for steam locomotives 100 miles per
hour can be taken as the maximum
limit for useful work so far as the
boiler is concerned. For the engine
the Limitation is far below this and is
pally to the valve and waive gear
which at such speeds allow but small
volume of steam into the cylinder
and produce high back pressure In It's
escape through the exhaust nozzle.
The indicator card is very narrow and
the mean effective pressure low: The
rotary valves on the Cor1tss principle
which are now in use on a number
of locomotives on a western road have
some advantage over the slide valve
at high speeds. They have double
port opening and quicker admission,
closing and exhaust, which should
produce a fuller card at the higher
speeds we are considering.
Rock Islands Good Engines.
The four-cylinder simple locomotive
recently built for the Rock Island
should have some advantage for high
speed work although there is only one
valve for two cylinders, but it can be
set for the most advantageous d1str1-
four cylinder engine is also we'll
adapted to high speed work. due to
the fact that the steam enters all the
cylinders at high pressure and there
fore at high velocity and should pro-
duce a much higher mean effective
pressure at a given speed than where
compound cylinders are used. The
new three-cylinder simple LOGON olive
on the Reading has each cylinder sup
piled with its own piston valve, the
two outer ones being actuated by the
Walschaerts valve gear and the inner
ones by the Joy valve gear. This ar
rangement is also favorable for high
speed work. as there is provided large
port area, large cylinder volume and
high steam velocity to each cylinder.
The engine has hauled a train weigh
ing 800 tons at a speed of go miles per
hour for a short distance, but only
attained this speed on slightly fall
ing gradient.
We have indicated some of the de-
Eirable features of high speed loco
motives and some means by which
they may be improved. but nothing
has thus far been devised which will
nary express trains on a continuous
schedule exceeding 65 or 20 miles per
hour, while 1t has been clearly demon
strated that continuous electric trac-
ton is possible at 100 miles per hour.
1t has also been frequently demon
strated that the danger of derailment
from Irregularities in the track in
creases with increase of speed. For
this reason the speed of most ex
press trains is limited as much by
track conditions as by the horsepower
of the locomotive, and it is common
practice to reduce speed on approach
ing curves of more than ordinary de-
gree. On account of this requirement
1t is desirable to run fast on tangents
in order to make the average speed
approach fairly high speed schedule
The conditions of high speed trac-
tion on the main lines. then. appear to
be first. that for continuous operation
at 80 to 100 miles per hour the curves
must not exceed one degree. which is
more than one mile radius, and would
mean new alignment for any of our
trunk lines; second, that if such a line
was provided it could only be oper-
ated at such speeds by electric loco
motives; third. that on present lines
having long tangents the steam loco
motive can be adapted to occasional
spurts of very high speeds by auxil-
larry cylinders or turbines which are
specially designed for high speed re-
ouirements