SPEED IN LOCOMOTIVES.
Scribner'sJanuary to June, 1892
THE LIMITATIONS OF FAST RUNNING.
By M. N. Forney.Editor, Railroad and Engineering
RACING seems to be a natural instinct in human beings as well
as in other animals. In our natures this instinct seems to be
stimulated, and not satisfied, by the means which science has
supplied for achieving rapid movement, and modern appliances are
now put into requisition for the gratification of this natural
bent. Whole nations are now interested in the "records"
of transatlantic steamers, and in the time made by the Flying
Dutchman or the Columbian Express. Each gain in speed, in both
land and water, seems to add to the eagerness with which people
inquire about future possibilities.
When Stephenson's Rocket, on its trial trip, made a speed of
nearly thirty miles an hour, doubtless those who saw and heard
of it were as anxious then to know how much faster a locomotive
could run as we are to-day when we travel more than twice as fast.
In speculating on this subject a sort of single-rule-of-three
logic is sometimes applied to it which is apt to lead to erroneous
conclusions. Mechanical dialecticians assume as a premise that
the improvements which have been made in locomotives in sixty
years have resulted in doubling the speed, therefore in sixty
years more we will be able to travel twice as fast as we do now.
Or, in other words, sixty years ago we travelled 30 miles an hour
and now we travel 60, therefore as 30 : 60 :: 60 :120= the speed
at which we will travel sixty years hence. There are, however,
greater difficulties in the way of doing this than appear from
this arithmetical syllogism. The aim of this brief discourse on
railroad speed will be, to use words of Mr. Carlyle which referred
to quite a different subject, "to tell practically, in reasonable
words, what the possibilities, limitations, difficulties, laws,
and conditions of the enterprise are."
It may be said, in the first place, that to move an ordinary
car on a level railroad track requires the exertion of a horizontal
pull of from four to five pounds for each ton (of 2,000 pounds)
of its weight. That is, if it weighs twenty-five tons and a rope
is attached to it, it will be necessary to exert a pull of from
one hundred to one hundred and twenty-five pounds on the rope
to keep the car moving at a slow speed after it is started. As
the speed increases, the "resistance"as it is
calledof the car also increases: that is, more force or
pull must be exerted to keep it moving. The exact rate with which
this resistance is augmented when the speed is accelerated, and
the laws governing it, are still imperfectly understood. Our knowledge
of the subjectespecially that relating to the higher speedsis
only approximate, and probably not a very close approximation
either. Tables have been compiledfrom such data as are availableshowing
the resistance of trains at different speeds. The accompanying
diagram is constructed from such a table, in which the resistances
have been plotted, so as to show graphically the rate at which
they increase. The speed in miles per hour is laid off on the
base line 0-100, each space between the vertical lines representing
five miles per hour. The spaces between the horizontal lines represent
the resistance in pounds per ton. The resistance per ton for the
speed represented by each vertical line is laid off from the base
line, and a curve, A B C, is drawn through the points thus
laid down. Its vertical distance, as 40 B above the base
line, at any point 40, thus represents the resistance at the speed
indicated by that point. At sixty miles an hour, it will be seen
the curve shows that the resistance is twenty-five pounds per
No data exist
to show how much power is required to pull a train at a speed
greater than seventy miles per hour; but if the curve in the diagram
is continued beyond the vertical line representing seventy miles
per hour, as shown by the dotted line C D, it will indicate
approximately the rapid rate at which the resistance probably
increases above that speed.
It must be remembered that to maintain a high rate of speed
there must be a continuous pull exerted on the drawbar of a locomotive,
and that the relative amount of this pull at different speeds
is indicated by our diagram.
This propelling power of a locomotive is due to the pressure
which is exerted on the pistons of two cylinders by the expansive
action of the steam. Each piston makes two strokes, or moves twice
through the whole length of the cylinder during each revolution
of the driving-wheels.
It will be assumed that we have a locomotive with driving-wheels
six feet, and cylinders eighteen inches, in diameter, and pistons
which have two feet stroke. Such an engine with its tender would
weigh about ninety tons. Each cylinder would have a capacity of
about three and a half cubic feet. Excepting in starting a train,
these cylinders are filled only partly full of steam from the
boiler, for two reasonsfirst, because it would be a very
wasteful use of steam to fill them entirely full, and second,
it would be impossible for the boiler to supply enough to fill
them when running fast. Therefore steam is "cut-off,"
as it is termedthat is, it is admitted to the cylinder during
a third or a fourth or some other fraction of the stroke, and
the opening which admits it to the cylinder is then closed, and
the steam which has been admitted is allowed to expand while the
piston is moving to the end of its stroke.
To show how the speed and load of a locomotive are limited
by the supply of steam, it will be supposed that for each stroke
of the pistons the cylinders are filled one-third full of steam
of the boiler pressure of one hundred and sixty pounds. This is
expanded in the cylinder during the completion of the stroke of
the pistons. For each revolution of the wheels, therefore, four-thirds
of a cylinder full of steam would be used. Wheels six feet in
diameter would turn 280 times in running a mile, and at 60 miles
an hour they would turn 16,800 times in that period, and would
consume 79,161 cubic feet of steam. On making comparisons of the
quantities of steam of varying pressures used, it is best to do
it in terms of its weight, because that will represent the actual
quantity irrespective of its pressure or volume; 79,161 cubic
feet of steam of 160 pounds pressure per square inch will weigh
It has been found that the greatest amount of coal which can
be burned in an hour, on each square foot of grate of a locomotive,
is about two hundred pounds. A locomotive such as we have described
would have about twenty-four square feet of grate area, so that
4,800 pounds of coal is the maximum amount which could be burned
in its fire-box per hour. At this high rate of combustion each
pound of fuel would not evaporate more than about six pounds of
water, and, therefore, not more than 28,800 pounds of water could
be evaporated in such a boiler per hour. This, it will be seen,
would not be sufficient to supply the cylinders under the conditions
of working described. Consequently, in running an engine at 60
miles an hour we would be obliged to reduce the quantity of steam
admitted to the cylinders, which would either diminish the load
which could be hauled or the speed of running. If instead of cutting
off the steam at 8 inches and filling the cylinders one-third
full of steam during each stroke, it was cut off at 7 inches,
the consumption per hour would be reduced to 27,207 pounds, which
is somewhat less than the maximum quantity which it is possible
for the boiler to supply. Not counting any back pressure or any
other losses or waste, the maximum tractive or pulling force which
this quantity of steam would exert would be equal to 10,700 pounds.
As the resistance at this speed, as shown by the diagram, is 25
pounds per ton, the maximum load which could be hauled would be
428 tons, including the weight of the engine and tender, or 338
tons without. Practically, an ordinary locomotive would not do
nearly as much work as this, on account of the back pressure in
the pistons, waste, friction of the machine, and losses of various
kinds in the engine.
If the speed were increased to 90 miles an hour, then the number
of strokes made by the pistons would also be increased in like
proportion. The capacity of the boiler to generate steam would,
however, be no greater at this high velocity than it was at 60
miles an hour. Therefore, instead of cutting off the steam at
7 inches of the stroke, we would be obliged to cut it off at about
5 inches. The tractive force exerted by this steam could not be
more than 8,494 pounds. The resistance of the train would, however,
according to our diagram, be about 51 pounds per ton. The maximum
load which could be hauled would therefore not exceed 166 tons,
including the weight of engine and tender, or 76 tons without.
In practice this could not be done with an ordinary engine, on
account of the losses and waste of various kinds already referred
These calculations therefore indicate that at a speed of
100 miles per hour on a level track, an ordinary locomotive would
do tittle more than pull itself and its tender, and maintain the
speed for any considerable time. Of course, on an ascending
grade it could not do this.
Before considering the possibilities of the future, some of
the other obstacles in the way of making very fast time must be
If the driving-wheels of a locomotive are three feet in diameter,
their circumference will be nearly nine and a half feet long,
and in travelling a mile, or 5,280 feet, they must turn 560 times.
A speed of thirty miles an hour is equal to one mile in two minutes,
so that, at that velocity, wheels three feet in diameter must
be turned 280 times per minute. We may double this speed by turning
the wheels twice as often in a given time, or by making them twice
as large, or six feet in diameter, and turn them the same number
of revolutions in any given period. To quadruple the speedthat
is, to run 120 miles per hourwheels three feet in diameter
would have to turn 1,120 times per minute, or if they revolve
only 280 times, they must be 12 feet in diameter to make that
speed. Big driving-wheels in a locomotive always excite popular
admiration; but in designing a locomotive an engineer cannot allow
his imagination to guide him. He is absolutely confined to certain
limits, such as the weight which can be carried on each wheel,
the space between the rails, or the "gauge" of the track,
as it is called, the length of the wheel-base which will permit
the engine to run around curves, the height of tunnels overhead,
As a practical illustration of this, we may take the limitations
which would be imposed on a designer of an express locomotive
of the heaviest and most powerful type now used. The maximum which
is now allowed in this country on each driving-wheel is 20,000
pounds. More than this would be considered injurious to both the
rails and wheel-tires, and would be likely to cause the axles
to heat, owing to the excessive friction due to the weight on
the journals. The whole length of the wheel base must not exceed
24 or 25 feet, and if a truck is placed in the usual position
under the front end of the engine, it will carry about a third
of the weight of the engine, or one-half as much as the four driving-wheels.
The total weight of such a locomotive, without its tender, will
therefore be as follows:
20,000 pounds on each of four driving-wheels 80,000
10,000 pounds on each of four truck-wheels 40,000
Total . . . . . . . . . . . . . . . . . . . . . . .120, 000
A still more powerful locomotive could be constructed if we
used six driving-wheels, but for the present only the eight wheeled
engine will be considered.
The problem the designer, then, has to solve is to proportion
the parts of his locomotive so as to produce the most efficient
machine of that weight. During each revolution of the wheels the
pistons must be moved backward and forward through their whole
stroke. At 70 miles an hour a six-foot wheel of a locomotive would
revolve more than five times in a second. During every revolution
each piston and its connection must start and stop twice. They
come to a state of rest at the end of each stroke, and must be
started and their motion accelerated to a speed of nearly 35 feet
per second, in less than one-tenth of a second, and then come
to a state of rest again in the same time. When it is remembered
that each of the pistons, with their moving connections, weighs
considerably over 500 pounds, the amount of power required to
move them, and the disturbing effect which they exert on being
started and stopped twice during each revolution at these high
speeds may be imagined. To neutralize these disturbing effects
balance-weights are placed in the wheels opposite the cranks.
These accomplish their purpose, however, only partially, for the
reason that they move in a circle, while the piston and other
reciprocating parts have only a horizontal motion. Consequently,
while the balance-weights may be made to neutralize the horizontal
motion and momentum of the pistons, etc., the weights themselves
thus produce a vertical disturbing force which at high speeds
has been said to be so great as to bend the rails on which the
locomotives are running. For these reasons a compromise is usually
made by balancing the reciprocating parts only partially, which
lessens the vertical disturbance but does not entirely compensate
for the horizontal momentum of the reciprocating parts. Therefore,
a locomotive at best is an unstable machine at high speeds.
The obvious expedient for getting over this difficulty is to
increase the size of the wheels of fast engines, and it seems
like a very simple inference to assume that, if a locomotive with
wheels 3 feet in diameter will run satisfactorily at speeds of
30 miles per hour, therefore, to run at 60 miles an hour all we
need do is to increase the wheels to 6 feet, and then with the
same number of revolutions we shall make double the speed, and,
with wheels 7½ feet in diameter we can run 75 miles an
hour as easily as we can travel 30 miles with 3-foot wheels. But
in enlarging the size of wheels we soon reach limitations, owing
to their increase in weight and in that of other parts. The weight
of a wheel increases about as the square of its diameter. If its
diameter is enlarged, the size of the cylinders and their connections
must all be larger and heavier. This makes necessary stronger
frames and an increase in size and weight of many of the other
parts. Now, the importance of having ample boiler capacity has
been explained. If, then, the weight of our hypothetical locomotive
is limited to 120,000 pounds, every extra pound of weight which
is put into the wheels, cylinders, frames, etc., means that the
weight of the boiler must be that much less. In other words,
the bigger the wheels are, the tighter and smaller must be the
boiler. The problem which the locomotive designer, then, has
to consider and determine, is the sum of the advantages which
will result from an increase in the size of the wheels, and a
diminution of that of the boiler, or vice versa.
It may be said that no common agreement with reference to the
size of locomotive wheels has ever been reached by locomotive
engineers. Practice seems to vacillate: at one time wheels as
large as 10, and we believe 12, feet in diameter were employed,
but these excessively large sizes have now been abandoned. At
present American practice seems to incline toward larger sizes.
In running the Empire Express on the New York Central road, engines
with wheels 6 feet, and others of 6 feet 6 inches diameter have
both been used, with the result that the service of the engines
with the larger wheels has been decidedly the most satisfactory.
As an essential thing to do in running fast is to turn the
wheels rapidly, it might be thought advisable to increase the
power available for this purpose by enlarging the cylinders. Here,
too, we encounter a difficulty. If the cylinders are larger than
a certain size, the force which will be exerted by a given steam
pressure to turn the wheels will be greater than their "adhesion"
or friction on the rails, and they will slip, and we shall have
what engineers call a "slippery engine." The cylinders,
driving-wheels, the weight on them, and the steam pressure must,
therefore, bear such proportions to each other that the pistons
can exert what is called a "rotative effect" on the
wheels equal to, but not much in excess of, their adhesion or
friction on the rails.
Another obstacle in the way of running at high speeds is that
of getting the steam into the cylinders, and have it exert the
requisite pressure on the pistons, and then get it out again,
so that there will not be any, or as little, back pressure as
possible in front of the pistons. The quickness with which the
steam must act may be understood from the figure on next-page,
which represents a section of a locomotive cylinder with its piston.
As already remarked, at 70 miles per hour this action must begin
and be completed in less than a tenth of a second. What adds to
the difficulty is the fact that, in order to stimulate the fire,
the opening in the ends of the exhaust-pipes through which the
steam escapes must be more or less contracted, so as to produce
a blast in the chimney to stimulate the fire. This, of course,
obstructs the free flow of the escaping steam from the cylinders,
and produces more or less back-pressure on the pistons.
The mechanism for admitting the steam to, and exhausting it
from, the cylinders, performs a very important part in fast-running
engines, as the action of the steam in the cylinders depends very
much on that of the slide-valves, and no problem connected with locomotive construction
has been the subject of so much thought and invention as that
of "valve-gear," or the mechanism for working the valves.
It has been analyzed mathematically, elucidated graphically, demonstrated
mechanically, and tested experimentally in every conceivable way.
Numberless inventions have been made of mechanism for this purpose,
but what is called Stephenson's "link motion," which
was adopted by him, although he was not its inventor, still holds
its supremacy among valve-gears, and there are at present no signs
that it will soon lose it.
There is much less difficulty, however, in getting the steam
into the cylinders than there is in getting it out, because there
is a pressure in the boiler of from 150 pounds to 200 pounds per
square inch to force it in; but after it has done its work in
the cylinders it has been expanded and its pressure and temperature
very much reduced, so that it is partially condensed or liquefied,
and consequently does not move with as much celerity as "live"
steam, as it is called, fresh from the boiler does. The result
is that at high speeds there is always an increase of back pressure
in front of the pistons, which has a retarding effect, at the
time when it is essential that the maximum power should be exerted
by the pistons. If the engineer tries to compensate for this by
admitting more steam in front of the pistons, then the demand
on the boiler becomes so great that it cannot supply it. Besides
this, the escaping steam then has not had sufficient opportunity
to expand, and escapes up the chimney with such violence as to
"tear the fire to pieces," as firemen express it. An
engineer who is running an engine must therefore be careful, at
high speeds, not to use more steam in an engine than the boiler
can supply, and generally the limitations to speed in a locomotive
are the same as those of a horsewant of wind.
A writer on this subject has formulated the maxim, that "within
the limits of weight and space to which a locomotive boiler is
necessarily confined it cannot be too big." Certainly the
larger it is the greater will be the efficiency of the engine,
and the more economical will it be in the use of fuel.
The limitations in the weight of a locomotive have been explained.
Its size is necessarily confined by the distance between the rails,
or their "gauge," as it is called. This on ordinary
roads is 4 feet 8½ inches. The flanges of the wheels are
inside of the rails, so that the distance between the tires is
4 feet 5-and-three-eighths inches. The frames of the engine are
ordinarily inside of the tires and the fire-box inside of them.
Therefore, as usually constructed, it can be only about 3 feet
7 or 8 inches wide. The result is that this part of the boiler
is contracted in one of its vital parts, and it has been remarked
that the back end of a large locomotive boiler looks like a broad-shouldered
woman in tightly-laced corsets. Under these conditions the vital
parts of both the woman and the locomotive are contracted. To
partly obviate this difficulty in locomotives, their fire-boxes
are now often placed on top of the frames. This allows them to
be about 8 inches wider than they could be if they were between
the frames, but the height of the firebox must then be reduced.
In the Wootten locomotivenamed after its inventorthe
fire-box is located entirely above the wheels, and can then be
made as wide as the widest part of the locomotive. This necessarily
raises the centre of gravity of the boiler and reduces the depth
of the fire-box.
From what has been said it will be seen what an exceedingly
difficult problem is presented to a locomotive engineer in designing
an engine for very high speeds. It is largely a matter of relativity
and proportion. A maximum speed can be attained only when the
different organs, asthey may be called, hear the proper
proportion to each other, and the ability of the designer is shown
by his recognition of the relative value and importance of the
proportions of the different parts.
The question whether we shall ever be able to travel on railroads
at a regular speed of 100 miles per hour is often asked. Most
railroad managers are disposed to answer the question as David
Copperfield replied to the disparaging remark about the inability
to swing a cat in his room. He replied that he didn't want to
swing a cat, and so most managers say they don't want to travel
at the rate of 100 miles per hour. Those who know most about the
risks of such speeds seem least inclined to encounter them. Every
school-boy knows that after a kite has reached a certain height,
no amount of added string will allow it to fly higher. The span
of a bridge may be so long that it will not carry its own weight.
So our diagram of train resistance shows that when we get above
70 miles per hour, the resistance of the locomotive and that of
the cars becomes so great that it will do no more than pull itself
and its tender. When this point is reached, further increase of
speed becomes impossible with the locomotives we are now using.
Besides the difficulties which have been pointed out, there
is the risk, at high speed, of the breakage of the coupling-rodsby
which the cranks on adjoining wheels are coupled togetherowing
to the strain to which they are subjected by centrifugal force.
This danger increases with the distance apart of the wheels and
the length of the rods, and the centrifugal force which acts on
the rods increases with the number of revolutions of the wheels;
and consequently, as large wheels make fewer revolutions at a
given speed of train, the centrifugal force exerted on the rods
is then inversely to the diameter of the wheels, or, in other
words, the larger they are the less is this force.
With high speeds and the heavy express engines which are now
used, a good deal of trouble is also experienced from the heating
of the journal bearings of the driving-axles, owing to insufficient
bearing surfaces. Their size is limited when the fire-boxes are
placed between the frames, because in order to make the former
as wide as possible, the frames are placed as far apart as the
wheels will permit. This shortens the journals, and consequently
diminished the surface of their bearings. The cure for this is
to bring the frames nearer together and thus lengthen the journals.
There is no objection to doing this when the fire-boxes are not
between the frames.
It may therefore be inferred that there is not much probability
of attaining regular and continuous speeds of 100 miles per hour
with our present locomotives. Their fire-boxeswhich perform
the same functions for the machines that their stomachs do for
animalsare, with the present system of construction, necessarily
contracted in size. The weight of the whole locomotive being fixed,
the dimensions of the different parts are also limited.
It is proverbially dangerous to prophesy when you are not quite
sure, and if prognostications are based upon calculations the
mendacity of figures may rise up hereafter to deprive the prophet
of all honor.
From what has been said, however, it will be seen that fast
running is largely a question of steam production. Given a
boiler which will generate enough steam, and the other problems
are of comparatively easy solution. The difficulty is to get the
boiler sufficiently large within the limits of size and weight
to which it must be confined.
It will be safe to say that to be able to travel continuously
at 100 miles per hour we must have either boilers or fuel which
will generate more steam in a given time than those we are using
now do, or our engines must use less steam to do the same work,
or, what is more probable still, we must have all three of these
features combined. In the locomotive of the future the action
of the reciprocating parts will probably be more perfectly balanced
than it now is; coupling-rods will either be dispensed with altogether
or their risk of breakage will be lessened by placing the driving-wheels
near together, and both this danger and the disturbing effect
of the reciprocating parts will be lessened by increasing the
size of the wheels. To enable the engine, or, rather, its journals,
to "run cool," the journals and their bearings will
be increased in size so as to have ample surface to resist wear.
Just how these improvements will be made, it is perhaps too
early to predict. Coming events are, however, already casting
their shadows before them, and there are indications that the
improvements which are here foreshadowed, or some of them, are
in process of evolution. In Mr. Webb's new engine, Greater Britain,
recently built for the London & Northwestern Railway, the
boiler has been materially increased in size, and he reports the
remarkable performance of evaporating nearly eleven pounds of
water per pound of coal while pulling a heavy train at the rate
of over 44½ miles per hour. This engine is compounded so
as to use steam with the greatest economy, and is without coupling-rods.
These are dispensed with by using three cylinderstwo high
pressure and one low pressure. The two former are connected to
the back pair of driving-wheels and the latter to the front pair.
By this means both pairs of wheels are driven by separate cylinders.
A new express locomotive is now in process of construction in
this country with a fire-box about twice as wide as those ordinarily
used. The problem of improving the balancing of engines is attracting
much attention, and the bearing surfaces of many recent locomotives
have been materially increased. Driving-wheels have been enlarged
in size with the increase in speed, and if the march of improvement
continuesand there is no reason for thinking it will notthe
anticipation that we shall travel at the rate of 100 miles per
hour may be fulfilled while some of us are left here to see it.
TRAIN-SPEED A QUESTION OF TRANSPORTATION.
By Theodore N. Ely.General Superintendent of
IT is a pleasing sign of the times to witness the growing interest
taken by the general public in railway matters. This demand has
caused the daily press and magazines to give considerable space
to a presentation of such of the problems as can well be treated
by them. As a supplement to the more detailed and technical discussions
of the scientific journals, the opinions of the press will be
welcome to all professional railway officers; and without doubt
will go far toward securing high standards of management. Much
has been written relating to speed of trains, the different phases
of which have been so well explained that anything to be said
at this time must in a measure go over oft-trodden ground.
But what is a fast train? The very difficulty in giving a proper
definition here helps to prove that speed is a relative term.
"Will you walk a little faster?" said a
whiting to a snail,
"There's a porpoise close behind us, and he's treading on
This couplet suggests to me, as it probably did not to its
author, a perfect description of a slow-moving traineven
to the necessity for, and evident absence of, the Block System!
But it is not so easy to say what speed entitles a train to the
distinction of being called fast.
It can hardly be said that the possible speed of locomotives
has improved in the last fifteen or twenty years. The records
would no doubt show that the locomotives of that period made,
on occasions, as fast runs with trains within their capacity as
those of the present day. It is indeed reassuring when we recall
the high-speed journeys taken safely over the tracks and alignment
which existed twenty-five years ago. We were either very brave
or very ignorant in those days; for, from our present point of
view, we would regard the running of trains at such speed over
such tracks as extremely hazardous. There were accidents, to be
sure, but not of such frequency as the railroad engineer of today
Briefly, the radical improvements which have been accomplished
may be comprised under three general headsRoadway, Equipment,
ROADWAY.Some twenty-five years ago the Pennsylvania
Railroad adopted broken stone as best meeting the conditions of
a good track foundation; at the same time the dimensions and number
of ties were fixed, and finally the rails and turnouts were laid
according to carefully considered rules. The weight of rails has
been increased, with a corresponding improvement in fastenings;
the old turnouts have given place to those of more modern design;
but the foundation is much the same as that first adopted. Closely
related to the roadway are crossings at grade. These have, from
time to time, been abolished as detrimental to the safe passage
EQUIPMENT.In equipment, the locomotive has been
thoroughly redesigned and made stronger in all its parts. The
air-brake applied to its driving and tender wheels, has made it
possible not only to stop itself quickly, but assist in retarding
the train, as well. The strength of passenger cars has been increased,
until they have reached a weight of 27 tons, and the couplings
and platforms have been greatly improved. Sleeping-car construction
has likewise advanced, until the more modern ones have reached
a weight of nigh 50 tons. The air-brake has become indispensable
as a condition of safety in fast-moving trains.
SIGNALS.In the early days of railways there was
nothing that could properly be dignified by the name of signal.
By slow degrees, as is usual in matters involving questions of
safety, a high state of development has at last been reached.
The best systems of signalling and interlocking are marvels of
mechanical skill and ingenuity, and command the respect due to
their wonderful reliability.
The pirate of the Mediterranean would be flattered, indeed,
if he could know that the semaphore signal of warning he was wont
to display from the rock of Gibraltar had become the recognized
danger signal of modern railways.
It may be interesting to note in passing, a few instances of
train movements which have come under the writer's observation.
Nearly sixteen years ago, or to be exact, in June, 1876, a Pennsylvania
Railroad standard locomotive drawing a train of two sleeping-cars
and a dining-car, covered the distance between Jersey City and
Pittsburgh, 438.5 miles, without a stop, in 605 minutes, or an
average rate of 43½ miles an hour. This journey is interesting
as the longest known continuous run; and one which involved thorough
transportation arrangements for its movement, and great endurance
on the part of the locomotive. The special train was en route
to San Francisco, which city was reached in 84 hours and 17
minutes after leaving New York.
The train which conveyed our lamented President Garfield from
Washington to Elberon, September 7, 1881, was run under conditions
of great excitement and anxiety. His life hung upon a thread,
and any detention to the train would have resulted disastrously.
The heat was intense and prostration was imminent. The physicians
had fixed upon 30 miles an hour as the speed which would give
the least discomfort to the patient. After the train was well
under way, and without warning, an increase in speed was determined
upon, which reached 65 miles an hour before the journey was completed.
The orders for the transportation of this train were contained
in one message, and so skillfully was it worded that, despite
the changed conditions, there was not the slightest detention
from any cause.
A most noteworthy accomplishment was that of the Pennsylvania
locomotive which drew the special train of the delegates to the
International American Conference on their tour to the principal
cities east of the Rocky Mountains. This engine traversed the
rails of twenty distinct lines of railroad, and covered 10,000
miles in its course, without accident of any kind or unreasonable
Another example of endurance may be mentionedthe 126,000
miles made by one locomotive between Philadelphia and Washington
in the year 1891equal to five complete journeys around the
From the lessons of the past we may forecast the future, for
certainly we have reached that stage in railway progress where
we may assert with confidence that our acts and opinions are based
upon accumulated experience and not upon prophetic inspiration.
Guided by this light, let us consider what factor will control
the limit of speed in the passenger-trains of the future.
In the road-bed we shall have to demand that the alignment
be almost free from curvature, and the width between the tracks
be increased; that the foundation shall be stable and well-protected
from rain and frost; that land-slides and other accidental obstructions
shall be provided for; that the ties shall be firmly embedded;
that the rails shall be heavyone hundred pounds, or more,
if necessaryand securely fastened; that all frogs and switches
shall be proof against accidental misplacement or rupture; that
all drawbridges shall be made secure beyond question, and, finally,
that all crossings at grade be abolished. We must further insist
that a thorough system of supervision and inspection shall be
With a fulfillment of these conditions, which, professionally
speaking, are perfectly practicable, trains, so far as the road-bed
is concerned, may be run in safety as fast as any locomotive can
be made to haul them.
Of the locomotive, it may be said that, only with the improvements
in road-bed referred to, can its highest attainable speed be utilized.
The measure of the speed and capacity of the locomotive rests
in the fire-box, the length and breadth of which cannot exceed
certain dimensions. It therefore follows that when this furnace
is arranged to burn the maximum quantity of fuel, the steam-producing
limit will be reached, and with it the limit of speed. But this
steam must be used to the very best advantage, as relating to
the proportions of the locomotive, as well as to its type; the
first of these are already well known, and it will probably be
found that some form of compounding will suggest the type. With
these limitations the speed of locomotives with passenger trains
will not fall far short of 100 miles an hour; by which is meant
a sustained speed at that rate, as, for instance, a trip between
New York and Philadelphia in about one hour, or between New York
and Chicago in ten or eleven hours.
As to car equipment, it is probable that, with some change
in size and proportions of wheels, journals, and other parts of
the trucks, the best class of cars in present use would be suitable
for the highest speed. They should be made to run as noiselessly
as possible, that the occupants may be relieved from any feeling
of insecurity or nervous strain. The air-brake should be applied
in its best form to both locomotive and cars, so that every pound
of braking weight would become instantly available.
The above conditions have been cited in detail to show that
they all must be fulfilled in order to make possible our future
travelling at the rate of 100 miles an hour. Make possible, yes,
but only upon the fulfillment of one other condition, namely,
a clear track ahead; and this it is which brings us to the real
measure of speed, which is the question of transportation in its
strict sense. This limit will vary with the number of trains already
on the line and with the facilities for handling them. First of
all, we must know how soon after receiving warning of danger a
train, running a mile in 36 seconds, can be stopped. It is estimated
that if running at 60 miles per hour, with the full braking weight
of the train utilized, and the rails in the most favorable condition,
this train could be brought to a full stop in 900 feet; at 80
miles per hour, in 1,600 feet; at 90 miles per hour, in 2,025
feet, and, finally, at 100 miles per hour, in 2,500 feet. These
figures at once establish the fact that under the best possible
conditions the track must be kept clear of all obstruction for
at least 2,500 feet in advance of a train running at the highest
limit; but we must estimate the clearance for the worst conditions,
such as slippery rails, foggy weather, and unfavorable grades;
the personal equation of the engineman must also be considered
in a train covering 145 feet each second.
Would it, therefore, be too much to ask that the engineman
receive his warning at least three-quarters of a mile before he
must halt ?
The difficulties of arranging for the passage of trains of
this character are manifest; we are not speaking of special trains,
but rather of regular trains, running as frequently as may be
desired. It should be remembered that, in a two-hour run, the
fastest trains of to-day would require a leeway of an hour, and
slower ones would have to start proportionately earlier, or be
passed on the way.
The most improved forms of signalling and interlocking, be
they mechanical, pneumatic, electric, automatic, or otherwise,
which are so necessary to the safe movement of passenger trains,
may be introduced, but cannot be placed nearer together than three-quarters
of a mile. The very presence of these signals, while giving the
maximum safety, has in practice made prompt movement more difficult.
They are governed by fixed laws, which, if obeyed, make chance-taking
impossible, for trains must keep a prescribed distance apart,
and increase in speed involves greater intervals. This state of
affairs would point to the necessity for an increase in the number
of tracks, so that passenger trains could be grouped on the basis
of speed just as it has been found necessary already, on crowded
lines, to separate the freight traffic from the passenger.
If this be done, and unlimited track facilities are furnished,
the prompt despatching of trains would not be the ultimate measure
of speed; but such an outlay would be beyond all reason. It is
fair, therefore, we think, to rest the burden upon the transportation
shoulders, and predict that with it, and it alone, lies the practical
limit of the speed of railway trains drawn by steam locomotives.
A PRACTICAL EXPERIMENT.
By H. Walter Webb.3rd Vice-PresidentNew
York Central Railroad
ON September 14, 1891, a train, consisting of a locomotive
and three large private cars, made a run over the New York Central
& Hudson River Railroad, from New York to Buffalo, on a schedule
the most extraordinary on record, and which is destined to exert
an important influence on railroad travel during the next few
The engine was of a new class, especially designed for fast
passenger service by Mr. William Buchanan, the Superintendent
of Motive Power of the road, and built by the Schenectady Locomotive
Works, its total weight in working order being 100 tons. The aggregate
weight of the cars when empty was over 130 tons.
The journey from New York to East Buffalo, a distance of 436-and-32/100
miles, was made in 439-and-45/100 minutes. Allowing for time lost
in changing engines at Albany and Syracuse, and for cooling a
hot journal at Fairport, the run of 436.32 miles was made in 426
minutes, or at the rate of 61.44 miles per hour.
Previous to this run there were scores of records of fast time
made by passenger trains, special and regular, both in this country
and in England. Records of fast runs of 10, 15, or 20 miles were
exceedingly plentiful, but there were few records of long distance
runs that had attracted any special attention. The most remarkable
on record, and the ones that until last September were unequalled
in railroad history, were those made between London and Edinburgh,
in the summer of 1888, when the "race to Edinburgh"
was in progress between the London & Northwestern and the
Great Northern Railways of England. The distance over the former
is 400 miles, and the run was made daily on a schedule calling
for a speed of 53-and-one-third miles per hour. On the Great Northern
the distance is 393 miles, and the schedule in this case called
for a speed of 54 miles per hour.
These trains were run daily for many weeks, and were generally
punctual and within their schedule time. On several occasions,
however, they exceeded the schedule, and made what at that time
were regarded as phenomenal runs.
On August 13, 1888, the Northwestern train covered the distance
of 400 miles in 427 minutes, or at a rate of 56-and-one-fifth
miles per hour, and on August 31st the Great Northern train made
the run of 393 miles in 412 minutes, or at the rate of 57½
miles per hour. These individual runs were both remarkable, but
the daily running of the trains on their published schedules were
regarded by railroad men as still more extraordinary, and at that
time there were no schedule trains in this country that approached
them in point of speed. It must be remembered, however, that these
English roads are possessed of many advantages not enjoyed by
railroads on this side of the water, as, for instance, the long
and numerous tangents, the entire absence of grade crossings,
and, more especially, the light weight of the cars, 80 tons being
the maximum weight of the trains used in the "race to Edinburgh."
With equipment of the character required and used in this country,
provided as it is with all luxuries, conveniences, and comforts,
and a rate of two cents per mile, a train limited to the above
weight could not carry a sufficient number of passengers to enable
it to earn its running expenses.
Three years previous to these English records a special train
weighing 64 tons made a run on the West Shore road from Buffalo
to Weehawken in 9 hours and 23 minutes. In the published accounts
different allowances for stops were made, making the average rate
per mile vary from 51 to 54 miles per hour; either rate, however,
making it the best long-distance run on record in the United States,
until the run from New York to Buffalo, over the New York Central
& Hudson River Railroad, described in the beginning of this
That remarkable run eclipsed and left far behind all records
for long-distance runs formerly made in this country or England.
And to fully appreciate the importance of what was demonstrated
by it, we must remember that within six weeks after it was made
a passenger train was running between those cities on a schedule
two hours shorter than had at any time previously been made by
the fastest limited or mail train, and the air is even now full
of rumors of shorter time to be made on important lines between
great cities during the coming spring and summer, so that it is
not at all improbable, in view of the power now to be obtained
and the public demand for faster service, that in the near future
we shall see trains from New York to Buffalo in 7½ hours,
from New York to Boston in less than 4 hours, and from New York
to Washington in the same time.
But to railroad men and to those familiar with the characteristics
of the New York Central Railroad, between New York and Buffalo,
the record of the trip referred to was far more significant than
was indicated by the mere statement that the run had been at a
speed averaging 61-and-44/100 miles per hour.
They appreciated the fact that the journey out of the Grand
Central Depot, through the Fourth Avenue tunnel, over the Harlem
drawbridge, following the winding curves along the Harlem River
to Spuyten Duyvil, along the banks of the Hudson, through Yonkers,
Peekskill, and Poughkeepsie, rounding the curves of the Highlands,
and taking water twice from tanks between the tracks, meant frequent
reductions of speed in order to make the run in comfort and ease;
and from Albany, west, the long and heavy grade over the hill,
the thriving and prosperous towns of the Mohawk Valley, the slow,
tedious run through the streets of Syracuse, the viaduct at Rochester,
and the 11-mile grade at Batavia, all furnished reminders that
the train must have at times attained a high degree of speed to
have made the average mile at a rate of over 60 miles an hour.
A careful schedule of the running time of each mile was kept,
an analysis of which shows the following:
Four hundred and thirty-six miles were run in 426 minutes.
One hundred and thirty miles were run at a rate of less than
60 miles per hour.
One hundred and eighteen miles were run at a rate varying from
60 to 65 miles per hour.
One hundred and fifty-one miles were run at a rate varying
from sixty-five to seventy miles per hour.
Thirty-seven miles were run at a rate varying from seventy
to seventy-eight miles per hour.
The schedule and analysis certainly indicate a radical change
in the conditions affecting fast passenger train service in this
country. For many years the problem has been to obtain power sufficient
to draw heavy trains long distances at high rates of speed. The
above figures make it evident that steam will without difficulty
furnish power sufficient to take a train heavy enough to be profitable
over a long distance at a rate of speed very much in excess of
an average of 60 miles per hour; and attention is now diverted
from the motive power to other departments of the railroads and
a consideration of whether the roadbed, bridges, tracks, and safety
appliances are such as to permit the use of this power and speed
with entire safety and comfort to passengers.
The question then naturally arises, and is repeatedly asked:
If it is incumbent on most roads to raise their standards of roadways,
tracks, and bridges in order to permit of the use of the best
and most effective power, if the motive-power department is now
in advance of the other departments of railroads, wherein has
there been a change? On what lines and in what particulars has
the locomotive so developed in the past few years as to become
so much superior to what it was before?
The best and most complete answer is a comparison of the distinctive
features of the type of engine now in use on the New York Central
road for fast passenger service with those in use in the same
service two years ago. To fully appreciate the comparison it must
be remembered that the ability of a locomotive to draw a heavy
load a long distance at a high rate of speed is limited.
First, by the capacity of the boiler to furnish steam rapidly
enough and in volume sufficient to supply the demand.
Second, by the adhesion of the engine; that is, the resistance
which prevents or opposes the slipping of the driving wheels on
the rails, and,
Third, by its tractive power; that is, the force by which it
is urged onward by the pressure of steam in the cylinders.
The problem, therefore, presented to Mr. Buchanan in designing
the new type of passenger engine was to obtain greater boiler
capacity, greater adhesion, and greater tractive power. The engine
in use on the New York Central two years ago for the movement
of its fast passenger trains is a fair exponent of the best type
then in use or known. It rendered excellent service and attracted
frequent attention from motive-power men, both here and abroad,
on account of the work it did.
The fire-box of this engine was as large as it was possible
to make it, located where it was between the frames and driving-axles,
its width and length thereby being limited. The problem of increasing
the boiler capacity was for that reason a difficult one, and also
because the weight of the boiler itself in a locomotive and the
space it occupies is necessarily less in proportion to its capacity
than that of any other boiler, and for this reason it must produce
much more steam in a given space of time, in proportion to its
size, than a boiler of any other kind of engine.
To obtain the desired increased boiler capacity and heating
surface, Mr. Buchanan located the fire-box, which formerly was
between the sides or frames of the engine and between the axles
of the driving-wheels, on top of these frames and axles, and by
so doing obtained an increase in the width of the fire-box of
5½ inches and an increase in its length of 25 inches, being
an equivalent of nine and three-quarter square feet of
additional grate area. The boiler flues, which in the former engine
numbered 238, he increased to 268, and by the change in the fire-box
he was enabled to lengthen them 4½ inches, thus obtaining
an increased heating surface of two hundred and twenty-one
and a half square feet, the diameter of the boiler being increased
from 51 to 58 inches. With this increase in the grate area and
heating surface, the desired increase in boiler capacity was obtained.
To secure the adhesion the weight on the four drivers, which
formerly was limited to thirty tons, was increased to over forty,
or, over ten tons' weight on each driving-wheel.
Here, however, came in the question of road-bed, rail, and
bridges, as there are but few roads in the country that would
permit the use of an engine with such weight located on four drivers.
In this case, however, the matter had been fully provided for
and extensive alterations had been made to many bridges, a large
amount of work done on the road-bed, and the old and lighter form
of rail removed and replaced with the standard 80-pound section.
To increase the tractive power of the engine the cylinders were
enlarged 1 inch in diameter; being formerly 18 x 24, they were
now made 19 x 24.
All these changes had vastly increased the height and weight
of the engine, and by some faint-hearted friends the criticism
was freely made that its use would be destructive of roadway,
tracks, and bridges. These objections, however, were more than
met by a departure from the usual and by original methods of suspending
the engine on its springs. Formerly the springs were placed on
top of the driving-boxes; in this case they were located beneath
them and connected with equalizing bars, thus allowing the use
of a longer and more elastic spring than was formerly used, and
it has been demonstrated that these engines are less destructive
to road-bed and rail, are freer from the swaying motion usually
found in engines hung from above the driving-boxes, and ride smoother
and more comfortably than any in the service.
Of course, to obtain the speed that was sought, it was desirable
to increase the diameter of the driving-wheels; but this was not
done at first, nor until it was ascertained how successful had
been the efforts to increase the boiler capacity of the engine.
When it was found that this increase was ample, and even more
successful than had been hoped for, the driving-wheels were changed
and the new ones of 6 feet 6 inches in diameter, or 8 inches larger
than the old ones, were attached. The gain in speed is most apparent
and can well be appreciated when it is remembered that the large
driver makes 29.51 less revolutions in a mile than the small ones.
On a trip from New York to Albany the decrease in the number of
revolutions by the large 6 foot 6 inch wheel would be 4,219.93,
an equivalent of 86,154.09 feet, or a saving of nearly 16-and-one-third
miles. From New York to Buffalo the saving would be nearly 50-and-1/100
With a locomotive such as this for motive power it is not a
difficult matter to run profit-paying passenger trains over long
distances at a running rate of over a mile a minute; this, of
course, assuming we have proper character of roadbed and rails
and approved appliances to insure safety and rapid speed.
That the speed of passenger trains in this country is destined
to rapidly increase in the near future seems certain. There is
nothing in railroading that renders such large and quick returns
to the management as catering to the wants and desires of the
travelling public. Nothing so fully exemplifies this as the immense
change that has taken place in the past five years in the equipment
of through express trains from the seaboard to the West and Southwest.
The luxury and comfort that can today be obtained on one of
the many limited trains passing over any of the great trunk lines,
is in strong contrast to what was furnished five or six years
ago, and it would seem that there was not much room for further
improvement in that direction. What the public are now seeking,
and what will certainly be furnished, is fast time; and that this
is appreciated by railroad managers is well evidenced by the large
sums that are now being spent to perfect the roadways of the more
One word, in closing, in regard to the alleged danger of the
fast train. It is most emphatically untrue that it is more dangerous
than other trains. Those familiar with the subject will agree
that the very reverse is the case. As an eminent English authority
writes, "With picked engineers, trainmen, and firemen, with
the best and newest rolling-stock and the most perfect engines
the company possesses, with every signalman and flagman all down
the line on the qui vive, it is difficult to see where
there comes in any special source of danger." And in addition
to this, it must be remembered that fast trains such as are now
being run on many roads in this country would be simply impossible
without the vigorous discipline, the constant energy, the keenest
exactitude, and the care and attention to the details of the service
that is the surest and most effective guard against accidents.
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