empty returned; old machinery returned for repairs; steel car
springs; cotton softener; iron safes or vaults weighing over 12,000
lbs.; toys, etc.; portable powder magazines; coffee extract; empty
lard tierces returned; bolts and nuts in barrels; box and barrel
material; glass oil bottles in tin jackets; cast-iron radiators;
malleable iron castings; dried beef; sausage; straw paper; burlaps;
tobacco stems; hinges; straw braids; lawn hose reels; excelsior;
car-load rates.
SUBJECTS NOT ON THE REGULAR LIST.--Demurrage rules; adjustment of
rates as per instructions from the Executive Board; rates from
Cincinnati to Columbus, Eufaula, Opelika, etc.; classification of
iron tanks; classification of whiting; rates to Eufaula, Ala., from
East; rates to Milledgeville, Ga.; classification of cast-iron cane
mills; classification of locomotives and tenders.
SAFETY IN RAILROAD TRAVEL
BY H. G. PROUT.
The Possibilities of Destruction in the Great Speed of
a Locomotive--The Energy of Four Hundred Tons Moving at
Seventy-five Miles an Hour--A Look ahead from a Locomotive at
Night--Passengers Killed and Injured in One Year--Good Discipline
the Great Source of Safety--The Part Played by Mechanical
Appliances--Hand-brakes on Old Cars--How the Air brake Works--The
Electric Brake--Improvements yet to be Made--Engine Driver
Brakes--Two Classes of Signals: those which Protect Points
of Danger, and those which Keep an Interval between Trains
on the Same Track--The Semaphore--Interlocking Signals and
Switches--Electric Annunciators to Indicate the Movements--The
Block Signal System--Protection for Crossings--Gates and
Gongs--How Derailment is Guarded Against--Safety Bolts--Automatic
Couplers--The Vestibule as a Safety Appliance--Car Heating and
Lighting.
In 1829, when Ericsson's little locomotive "Novelty," weighing two
and a half tons, ran a short distance at the rate of thirty miles
an hour, a writer of the time said that "it was the most wonderful
exhibition of human daring and human skill that the world had
ever seen." To-day trains weighing four hundred tons thunder by
at seventy-five miles an hour, and we hardly note their passage.
We take their safety as a matter of course, and seldom think of
the tremendous possibilities of destruction stored up in them. But
seventy-five miles an hour is one hundred and ten feet a second,
and the energy of four hundred tons moving at that rate is nearly
twice as great as that of a 2,000-pound shot fired from a 100-ton
Armstrong gun. This is the extreme of weight and speed now reached
in passenger service, and, indeed, is very rarely attained, and
then but for short distances; but sixty miles is a common speed,
and a rate of forty or fifty miles is attained daily on almost
every railroad in the country. We cannot tell from the time-tables
how fast we travel. The schedule times do not indicate the delays
that must be made up by spurts between stations. The traveller
who is curious to know just how fast he is going, and likes the
stimulus of thinking that he is in a little danger, may find
amusement in taking the time between mile-posts; and when these
are not to be seen, he can often get the speed very accurately by
counting the rails passed in a given time. This may be done by
listening attentively at an open window or door. The regular clicks
of the wheels over the rail-joints can usually soon be singled out
from the other noises, and counted. The number of rail-lengths
passed in twenty seconds is almost exactly the number of miles run
in an hour.
[Illustration: Danger Ahead!]
But if one wants to get a lively sense of what it means to rush
through space at fifty or sixty miles an hour, he must get on a
locomotive. Then only does he begin to realize what trifles stand
between him and destruction. A few months ago a lady sat an hour
in the cab of a locomotive hauling a fast express train over a
mountain road. She saw the narrow bright line of the rails and
the slender points of the switches. She heard the thunder of the
bridges, and saw the track shut in by rocky bluffs, and new perils
suddenly revealed as the engine swept around sharp curves. The
experience was to her magnificent, but the sense of danger was
almost appalling. To have made her experience complete, she should
have taken one engine ride in a dark and rainy night. In a daylight
ride on a locomotive, we come to realize how slender is the rail
and how fragile its fastenings, compared with the ponderous machine
which they carry. We see what a trifling movement of a switch makes
the difference between life and death. We learn how short the look
ahead must often be, and how close danger sits on either hand. But
it is only in a night ride that we learn how dependent the engineer
must be, after all, upon the faithful vigilance of others. We
lean out of the cab and strain our eyes in vain to see ahead. The
head-light reveals a few yards of glistening rail, and the ghostly
telegraph poles and switch targets. Were a switch open, a rail
taken up, or a pile of ties on the track, we could not possibly see
the danger in time to stop. The friendly twinkle of a signal lamp,
shining faintly, red or white, tells the engineer that the way
is blocked or is clear, and he can only rush along trusting that no
one of a dozen men on whom his life depends has made a mistake.
When one reflects upon the destructive energy which is contained
in a swiftly moving train, and sees its effects in a wreck; when
he understands how many minute mechanical details, and how many
minds and hands must work together in harmony to insure its safe
arrival at its destination, he must marvel at the safety of
railroad travel. In the year 1887, the passengers killed in train
accidents in the United States were 207; those injured were 916.
The employees killed were 406, and injured 890.[20] These were in
train accidents only, it must be remembered, and do not include
persons killed at crossings, or while trespassing on the track,
or employees killed and injured making up trains. As will be seen
later, the casualties in these two classes are much greater than
those from train accidents. The total passenger movement in 1887
was equal to one passenger travelling 10,570,306,710 miles. That is
to say, a passenger might have travelled 51,000,000 miles before
being killed, or 12,000,000 miles before being injured. Or he might
travel day and night steadily at the rate of 30 miles an hour for
194 years before being killed. Mark Twain would doubtless conclude
from this that travelling by rail is much the safest profession
that a man could adopt. It is unquestionably true that it is safer
than travelling by coach or on horseback, and probably it is safer
than any other method of getting over the earth's surface that man
has yet contrived, unless it may be by ocean steamer. If one wants
anything safer he must walk.
* * * * *
[Illustration: Stephenson's Steam Driver-brake. Patented 1833.]
In considering the means that have been adopted to make railroad
travel safe, it must be remembered that there are very few devices
in use that are purely safety appliances. Nearly everything used on
a railroad has an economic or mechanical value, and if it promotes
safety that is but part of its duty. The great source of safety in
railroad working is good discipline. Of all the train accidents
which have happened in the United States in the last sixteen
years, nearly ten per cent. were due to negligence in operation,
and seventeen per cent. were unexplained. Of these no doubt many
were due to negligence, and many that were attributed to defects of
track and equipment would have been prevented, had men done their
duty. The value of mechanical appliances for safety is perhaps as
often overrated as underrated. Undoubtedly the best, and in the
long run the cheapest, practice will be that which combines in
the highest degree both elements--disciplined intelligence and
perfection of mechanical details.
[Illustration: Driver-brake on Modern Locomotive.]
First in importance among the mechanisms which demand attention
here is the brake. From the beginning of railroads the necessity
for brakes was apparent, and in 1833 Robert Stephenson patented a
steam driver-brake (the brake on the driving-wheels). This was but
four years after the Rainhill trials, which settled the question
of the use of locomotives on the Liverpool & Manchester Railroad.
This early brake contained the principle of the driver-brake,
operated by steam or air, which has in late years come into wide
use. The apparatus is so simple that the cut representing it hardly
needs explanation. Admission of steam into the cylinder raised
the piston, which through a lever and rod raised the toggle-joint
between the brake-blocks and forced them against the treads of
the wheels. Essentially the same method of applying the retarding
force can now be seen on most passenger engines, and often, but not
so commonly, on engines for freight service. For various reasons
Stephenson's driver-brake did not come into use.
[Illustration: English Screw-brake, on the Birmingham and
Gloucester Road, about 1840.]
Innumerable devices for car-brakes have been invented, but they
divide themselves into two groups: those in which the retarding
force is applied to the circumference of the wheel, and those in
which it is applied to the rail. The class of brakes in which
the retarding force is applied to the rail has been little used,
although various contrivances have been devised to transfer a
portion of the weight of the car from the wheels to runners sliding
on the rails. There are many objections to the principle, and it
will probably never again be seriously considered by railroad men.
The apparatus is necessarily heavy, the power required to apply it
is great, and its action is slow. When brought into action it is
not as efficient as the brake applied to the tread of the wheels,
and the transfer of the load increases the chance of derailment.
[Illustration: English Foot-brake on the Truck of a Great Western
Coach, about 1840.]
Many different devices have been used to apply the brake-shoes to
the wheels, and various sources of power. Hand-power brakes have
been used, worked by levers, or by screws, or by winding a chain
on a staff; or, in still other forms, springs wound up by hand are
released and apply the brakes by their pressure. The momentum of
the train has been employed to wind up chains by the rotation of
the axles. This is the principle of the chain-brake, very much used
in England. This same source of power has been utilized by causing
the drawheads, when thrust in as the cars run together, to wind up
the brake-chains. Hydraulic pressure has been used in cylinders
under the cars; and finally air, either under pressure or acting
against a vacuum, has been found to be the most useful of all means
of operating train-brakes. Early forms of hand-brakes are seen in
the illustrations of some old English cars. The coach shows a
hand-brake operated by a screw and system of levers. By turning
a crank the guard puts in operation the system of levers which
apply the brake with great force; but the operation is slow. The
common hand-brake of the United States is too well known to need
illustration. With this brake a chain is wound around the foot of
a staff, and the pull of this chain is transmitted by a rod to the
brake-levers. This apparatus is simple, and when a train is manned
by a sufficient number of smart brakemen it is capable of doing
good service. This simple form of hand-brake will probably be used
in freight-car service until it is replaced by air-brakes, and the
various forms of chain and momentum brakes do not appear likely to
be much more used in the future than they have been in the past.
Therefore, no further space will be given to them.
The expression, electric brake, is now often heard, and requires
a word of explanation. There are various forms of so-called
electric brakes which are practicable, and even efficient, working
devices. In none of them, however, does electricity furnish
the power by which the brakes are applied; it merely puts in
operation some other power. In one type of electric brake the
active braking force is taken from an axle of each car. A small
friction-drum is made fast to the axle. Another friction-drum
hung from the body of the car swings near the axle. If, when
the car is in motion, these drums are brought in contact, that
one which hangs from the car takes motion from the other, and
may be made to wind a chain on its shaft. Winding in this chain
pulls on the brake-levers precisely as if it had been wound on
the shaft of the hand-brake. The sole function of electricity
in this form of brake is to bring the friction-drums together.
In a French brake which has been used experimentally for some
years with much success, an electric current, controlled by the
engine-driver, energizes an electro-magnet which forms part of
the swinging-frame in which the loose friction-pulley is carried.
This electro-magnet being vitalized, is attracted toward the axle,
thus bringing the friction-drums in contact. In an American brake
lately exhibited on a long freight train, a smaller electro-magnet
is used, but the same end is accomplished by multiplying the
power by the intervention of a lever and wheel. The other type of
so-called electric brake is that in which the motive power is
compressed air, and the function of the electric device is simply
to manipulate the valves under each car, by which the air is let
into the brake-cylinder or allowed to escape, thus putting on or
releasing the brakes. All of these devices have this advantage,
that, whatever the length of the train, the application of the
brakes is simultaneous on all the wheels, and stops can be made
from high speed with little shock. Up to two years ago it seemed
as if this advantage might be a controlling one, and compel the
introduction of electric brakes for freight service. Since then the
new "quick-acting" form of the air-brake has been developed, by
which the brakes are applied on the rear of a fifty-car train in
two seconds, and there is no longer any necessity to turn to other
devices. It is doubtful, therefore, if the additional complication
of electricity is widely introduced into brake mechanism for many
years, if ever.
It is now universally held that the brake, both for freight and for
passenger service, must be continuous; that is, it must be applied
to every wheel of every car of the train from some one point, and
ordinarily that point must be the engineer's cab. With the valve of
an efficient continuous brake constantly under his left hand, the
engine-driver can play with the heaviest and fastest train. Without
that instrument his work is far more anxious, and much less certain.
The continuous brake which to-day prevails all over the world, is
the automatic air-brake. In the United States much the largest part
of the rolling stock used in passenger service is equipped with the
Westinghouse automatic brake. A few roads peculiarly situated use
the Eames vacuum-brake. That brake is used on the elevated roads
of New York, and on the Brooklyn bridge roads. The Westinghouse
brake is also largely used in England, on the Continent of Europe,
in India, Australia, and South America. In the United States it is
being rapidly applied to freight cars also. This brake, therefore,
being the highest development of the automatic air-brake, and
the one most widely used, will be briefly described, as best
representing the most approved type of the most important of all
safety appliances.
The general diagram which is given on pages 196-97 shows all of
the principal parts as applied to a locomotive, a tender, and a
passenger car. The diagram is reduced from one prepared by Mr. M.
N. Forney for a new edition of his "Catechism of the Locomotive."
In the plan view are shown very clearly the hand-wheels, the
chains, the rods, and the levers by which the brake is applied by
hand. In passenger service the hand-wheels are rarely used, but
they are retained for convenience in switching cars in the yard,
and for those rare emergencies in which the air-brakes fail. Under
the middle of the car the ordinary pull-rod of the old hand-brake
is cut and two levers are inserted. One lever is connected with
the brake-cylinder, and the other with the piston which slides in
that cylinder. When air is admitted to the cylinder the piston is
driven out, and the brakes are applied exactly as they would be
were the chains wound up by turning the hand-wheels. Compressed
air is supplied to the cylinder from the reservoir near it, in
which pressure is maintained at from 70 to 80 pounds per square
inch by a pump placed on one side of the locomotive. The pump fills
the main reservoir on the engine, and also the car-reservoirs, by
means of the train-pipe which extends under all the cars. When
the brakes are off there is a full pressure of air in all of the
car-reservoirs and train-pipes. It is a _reduction_ of the pressure
in the train-pipes which causes the brakes to be applied.
[Illustration: Plan and Elevation of Air-brake
Apparatus.--Reservoirs and piping in solid black; brake gear
shaded.]
This fact must be borne in mind, for it is on this principle that
the automatic action of the brakes depends. If a train parts, or
if the air leaks out of the train-pipe, the brakes go on. This
automatic principle is a vital one in most safety appliances,
and it is secured in the case of the air-brake by one of the
most ingenious little devices that man ever contrived, that is,
the triple valve, which is placed in the piping system between
the brake-cylinder and the car-reservoir. This triple valve has
passages to the brake-cylinder, to the car-reservoir, to the
train-pipe, and to the atmosphere. Which of these passages are
open and which are closed depends upon the position of a piston
inside of the triple valve, and the position of that piston is
determined by the difference in air-pressure on either side of it.
Thus, when the pressure in the train-pipe is greater than that in
the car-reservoir, the triple valve piston is forced over, say to
the left, a communication is opened from the train-pipe to the
car-reservoir, and the air pressure in the latter is restored from
the main reservoir on the locomotive. At the same time a passage is
opened from the brake-cylinder to the atmosphere, the compressed
air escapes, the brake-piston is driven back by a spring, and
the brakes are released. If the pressure in the train-pipe is
reduced, the triple-valve piston is driven to the right (we will
assume) by the pressure from the car-reservoir, the passage to the
atmosphere is closed, air flows freely from the car-reservoir to
the brake-cylinder, and the brakes are applied.
The function of the engineer's valve is to control these
operations. Naturally the runner's left hand rests on this
instrument, which is fixed to the back head of the boiler. To apply
the brakes he turns the handle to such a position as to allow air
to escape from the train-pipe; to release, he turns it to allow air
to pass from the main or locomotive reservoir into the train-pipe,
and thence into the car-reservoir. It is hardly necessary to say
that the operation of the brake, which has been described for one
car, is practically simultaneous throughout the train. The brakes
on the driving-wheels of the engine are also automatically applied
at the same time as those of the cars and the tender.
In the plan on page 197 the several different positions of the
handle of the engineer's valve are indicated, and among them the
service-stop and the emergency-stop positions. The quickness of
the stop can be to some degree controlled by the rapidity with
which the air-pressure in the train-pipe is reduced. To make a
stop in the shortest possible time, the runner moves the throttle
lever with his right hand and shuts off steam, and with his left
hand moves the handle of the engineer's valve to the emergency
position, then pulls the sand-rod handle to let sand down to the
rails, and finally, if the engine is not fitted with driver-brakes,
he must reverse the engine and again open the throttle. These
movements must be made in order and with precision; and to make
them instantly and without mistake in the face of sudden danger
requires coolness and presence of mind. It sometimes happens that
an engine-runner reverses his engine before shutting off steam, in
which case the cylinder-heads will very likely be blown out and the
engine be instantly disabled. Then, if there are no driver-brakes,
the locomotive is worse than useless, for instead of aiding in
making the stop, its momentum adds to the work to be done by the
train-brakes. Again, if the air-pressure in the brake-cylinders
is so high, and the adjustment of the levers such that an instant
application of the full pressure will stop the rotation of the
wheels, and cause them to slide on the rails, the stop will take
longer than if the wheels continued to revolve. The maximum
braking effect is obtained when the pressure on the wheels is
as great as it can be without causing them to slide, and it may
happen that a quicker stop can be made by putting the engineer's
valve to the service-stop position than by trying to make an
emergency-stop. The runner must, therefore, be familiar with the
special conditions of his brakes, and must have that kind of mind
which can be depended upon to work clearly and quickly in a moment
of tremendous responsibility. Fortunately, such minds are not very
rare. The world is full of heroes who want only discipline, habit,
and opportunity.
The pressure of air in the main reservoir and the train-pipe is
maintained by the air-pump on the locomotive, the speed of which
is automatically regulated by an ingenious governor. It is the
throbbing of this vigilant machine which one hears during short
stops at stations. The air-pressure has been reduced in applying
the brakes, and the governor has set the pump at work.
All of those parts of the air-brake apparatus which are shown in
the diagram (pp. 196-97) can be easily seen on a train standing
at a station; but the curious traveller must be careful not to
mistake the gas-tank carried under some cars for the car-reservoir.
The gas-tank is about eight feet long; the car-reservoir is about
thirty-three inches.