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Scientific American Supplement, No. 446, July 19, 1884 online

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easily emptied. The wagons run on two lines, the one being for the
loaded trains, and the other for the empty trains.

The engineers and inspectors, in the discharge of their duties, make use
of the Liliputian carriages. The feet of the travelers go between the
wheels, and are nearly on a level with the rails; nevertheless, they are
tolerably comfortable. They are certainly the smallest carriages for
passengers that have ever been built; and the builder even prophesies
that these will be the first to enter into England through the Channel
Tunnel.

One of the most important uses to which a narrow gauge line can be put
is that of a military railway. The Dutch, Russian, and French
Governments have tried it for the transporting of provisions, of war
material, and of the wounded in their recent campaigns. In Sumatra, in
Turkestan, and in Tunis these military railroads have excited much
interest, and have so fully established their value that this paper may
confine itself to a short description.

The campaign of the Russians against the Turcomans presented two great
difficulties; these were the questions of crossing districts in which
water was extremely scarce or failed entirely, and of victualing the
expeditionary forces. This latter object was completely effected by
means of 67 miles of railway, 20 in. gauge, 14 lb. steel rails, with 500
carriages for food, water, and passengers. The rails were laid simply on
the sand, so that small locomotives could not be used, and were obliged
to be replaced by Kirghiz horses, which drew with ease from 1,800 lb. to
2,200 lb. weight for 25 miles per day.

In the Tunisian war this railroad of 20 in. gauge, 14 lb. rail, was
replaced by that of two ft. gauge, with 14 lb. and 19 lb. rails. There
were quite as great difficulties as in the Turcoman campaign, and the
country to be crossed was entirely unknown. The observations made before
the war spoke of a flat and sandy country. In reality a more uneven
country could not be imagined; alternating slopes of about 1 in 10
continually succeeded each other; and before reaching Kairouan 7½ miles
of swamp had to be crossed. Nevertheless the horses harnessed to the
railway carriages did on an average twelve to seventeen times the work
of those working ordinary carriages. In that campaign also, on account
of the steep ascents, the use of locomotives had to be given up. The
track served not only for the conveying of victuals, war material, and
cannon, but also of the wounded; and a large number of the survivors of
this campaign owe their lives to this railway, which supplied the means
of their speedy removal without great suffering from the temporary
hospitals, and of carrying the wounded to places where more care could
be bestowed upon them.

The carriages which did duty in this campaign are wagons with a platform
entirely of metal, resting upon eight wheels. The platform is 13 ft. 1
in. in length, and 3 ft. 11 in. in width. The total length with buffers
is 14 ft. 9 in. This carriage may be at will turned into a goods wagon
or a passenger carriage for sixteen persons, with seats back to back, or
an ambulance wagon for eight wounded persons.

For the transport of cannon the French military engineers have adopted
small trucks. A complete equipage, capable of carrying guns weighing
from 3 to 9 tons, is composed of trucks with two or three axles, each
being fitted with a pivot support, by means of which it is made possible
to turn the trucks, with the heaviest pieces of ordnance, on turntables,
and to push them forward without going off the rails at the curves.

The trucks which have been adopted for the service of the new forts in
Paris are drawn by six men, three of whom are stationed at each end of
the gun, and these are capable of moving with the greatest ease guns
weighing 9 tons.

The narrow-gauge railway was tested during the war in Tunis more than in
any preceding campaign, and the military authorities decided, after
peace had been restored in that country, to continue maintaining the
narrow-gauge railways permanently; this is a satisfactory proof of their
having rendered good service. The line from Sousse to Kairouan is still
open to regular traffic. In January, 1883, an express was established,
which leaves Sousse every morning and arrives at Kairouan - a distance of
forty miles - in five hours, by means of regularly organized relays. The
number of carriages and trucks for the transport of passengers and goods
is 118.

The success thus attained by the narrow-gauge line goes far to prove how
unfounded is the judgment pronounced by those who hold that light
railways will never suffice for continuous traffic. These opinions are
based on certain cases in the colonies, where it was thought fit to
adopt a light rail weighing about 18 lb. to 27 lb. per yard, and keeping
the old normal gauge. It is nevertheless evident that it is impossible
to construct cheap railways on the normal gauge system, as the
maintenance of such would-be light railways is in proportion far more
costly than that of standard railways.

The narrow gauge is entirely in its right place in countries where, as
notably in the case of the colonies, the traffic is not sufficiently
extensive to warrant the capitalization of the expenses of construction
of a normal gauge railway.

Quite recently the Eastern Railway Company of the province of Buenos
Ayres have adopted the narrow gauge for connecting two of their
stations, the gauge being 24 in. and the weight of the rails 19 lb. per
yard. This company have constructed altogether six miles of narrow-gauge
road, with a rolling stock of thirty passenger carriages and goods
trucks and two engines, at a net cost price of 7,500l., the engines
included. This line works as regularly as the main line with which it is
connected. The composite carriages in use leave nothing to be desired
with regard to their appearance and the comforts they offer. Third-class
carriages, covered and open, and covered goods wagons, are also
employed.

All these carriages are constructed according to the model of those of
the Festiniog Railway. The engines weigh 4 tons, and run at 12½ miles
per hour for express trains with a live load of 16 tons; while for goods
trains carrying 35 tons the rate is 7½ miles an hour.

Another purpose for which the narrow-gauge road is of the highest
importance in colonial commerce is the transport of sugar cane. There
are two systems in use for the service of sugar plantations:

1. Traction by horses, mules, or oxen.

2. Traction by steam-engine.

In the former case, the narrow gauge, 20 in. with 14 lb. rails, is used,
with platform trucks and iron baskets 3 ft. 3 in. long.

The use of these wagons is particularly advantageous for clearing away
the sugar cane from the fields, because, as the crop to be carried off
is followed by another harvest, it is important to prevent the
destructive action of the wheels of heavily laden wagons. The baskets
may be made to contain as much as 1,300 lb. of cane for animal traction,
and 2,000 lb. for steam traction. In those colonies where the cane is
not cut up into pieces, long platform wagons are used entirely made of
metal, and on eight wheels. When the traction is effected by horses or
mules, a chain 14½ ft. long is used, and the animals are driven
alongside the road. Oxen are harnessed to a yoke, longer by 20 in. to 24
in. than the ordinary yoke, and they are driven along on each side of
the road.

On plantations where it is desirable to have passenger carriages, or
where it is to be foreseen that the narrow-gauge line maybe required for
the regular transport of passengers and goods, the 20 in. line is
replaced by one of 24 in.

The transport of the refuse of sugar cane is effected by means of
tilting basket carts; the lower part of which consists of plate iron as
in earthwork wagons, while the upper part consists of an open grating,
offering thus a very great holding capacity without being excessively
heavy. The content of these wagons is 90 cubic feet (2,500 liters). To
use it for the transport of earth, sand, or rubbish, the grating has
merely to be taken off. In the case of the transport of sugar cane
having to be effected by steam power, the most suitable width of road is
24 in., with 19 lb. rails; and this line should be laid down and
ballasted most carefully. The cost of one mile of the 20 in. gauge road,
with 14 lb. rails, thirty basket wagons, and accessories for the
transport of sugar cane, is 700l., and the total weight of this plant
amounts to 35 tons.

Owing to the great lightness of the portable railways, and the facility
with which they can be worked, the attention of explorers has repeatedly
been attracted by them. The expedition of the Ogowe in October, 1880,
that of the Upper Congo in November, 1881, and the Congo mission under
Savorgnan de Brazza, have all made use of the Decauville narrow-gauge
railway system.

During these expeditions to Central Africa, one of the greatest
obstacles to be surmounted was the transport of boats where the river
ceased to be navigable; for it was then necessary to employ a great
number of negroes for carrying both the boats and the luggage. The
explorers were, more or less, left to the mercy of the natives, and but
very slow progress could be made.

On returning from one of these expeditions in Africa, Dr. Balay and M.
Mizon conceived the idea of applying to M. Decauville for advice as to
whether the narrow-gauge line might not be profitably adapted for the
expedition. M. Decauville proposed to them to transport their boats
without taking them to pieces, or unloading them, by placing them on two
pivot trollies, in the same manner as the guns are transported in
fortifications and in the field. The first experiments were made at
Petit-Bourg with a pleasure yacht. The hull, weighing 4 tons, was placed
on two gun trollies, and was moved about easily across country by means
of a portable line of 20 in. gauge, with 14 lb. rails. The length of the
hull was about 45 ft., depth 6 ft. 7 in., and breadth of beam 8 ft. 2
in., that is to say, five times the width of the narrow-gauge, and
notwithstanding all this the wheels never came off the line. The
sections of line were taken up and replaced as the boat advanced, and a
speed of 1,100 yards per hour was attained. Dr. Balay and M. Mizon
declared that the result obtained exceeded by far their most sanguine
hopes, because during their last voyage, the passage of the rapids had
sometimes required a whole week for 1,100 yards (1 kilometer), and they
considered themselves very lucky indeed if they could attain a speed of
one kilometer per day. The same narrow gauge system has since been three
times adopted by African explorers, on which occasions it was found that
the 20 in. line, with 9 lb. or 14 lb. rails, was the most suitable for
scientific expeditions of this nature.

The trucks used are of the kind usually employed for military purposes,
with wheels, axles, and pivot bearings of steel; on being dismounted the
bodies of the two trucks form a chest, which is bolted together and
contains the wheels, axles, and other accessories. The total weight of
the 135 yards of road used by Dr. Balay and M. Mizon during their first
voyage was 2,900 lb., and the wagons weighed 5,000 lb. Hence the
expedition had to carry a supplementary weight of 3½ tons; but at any
given moment the material forming this burden became the means of
transporting, in its turn, seven boats, representing a total weight of
20 tons.

It is impossible to enumerate in this paper all the various kinds of
wagons and trucks suitable for the service of iron works, shipyards,
mines, quarries, forests, and many other kinds of works; and we
therefore limit ourselves to mentioning only a few instances which
suffice to show that the narrow gauge can be applied to works of the
most varied nature and under the most adverse circumstances possible.

It therefore only remains to mention the various accessories which have
been invented for the purpose of completing the system. They consist of
off-railers, crossings, turntables, etc.

The off railer is used for establishing a portable line, at any point,
diverging to the right or left of a permanent line, and for transferring
traffic to it without interruption. It consists of a miniature inclined
plane, of the same height at one end as the rail, tapering off regularly
by degrees toward the other end. It is only necessary to place the
off-railer (which, like all the lengths of rail of this system, forms
but one piece with its sleepers and fish-plates) on the fixed line,
adding a curve in the direction it is intended to go, and push the
wagons on to the off-railer, when they will gradually leave the fixed
line and pass on the new track.

The switches consist of a rail-end 49 in. in length, which serves as a
movable tongue, placed in front of a complete crossing, the rails of
which have a radius of 4, 6, or 8 meters; a push with the foot suffices
to alter the switch. There are four different models of crossings
constructed for each radius, viz.:

1. For two tracks with symmetrical divergence.

2. For a curve to the right and a straight track.

3. For a curve to the left and a straight track.

4. For a meeting of three tracks.

When a fixed line is used, it is better to replace the movable switch by
a fixed cast-iron switch, and to let the workmen who drive the wagon
push it in the direction required. Planed switch tongues are also used,
having the shape of those employed on the normal tracks, especially for
the passage of small engines; the switches are, in this case, completed
by the application of a hand lever.

The portable turntable consists of two faced plates laid over the other,
one of thick sheet iron, and the other of cast iron. The sheet-iron
plate is fitted with a pivot, around which the cast iron one is made to
revolve; these plates may either be smooth, or grooved for the wheels.
The former are used chiefly when it is required to turn wagons or trucks
of light burden, or, in the case of earthworks, for trucks of moderate
weight. These plates are quite portable; their weight for the 16 in.
gauge does not exceed 200 lb. For engineering works a turntable plate
with variable width of track has been designed, admitting of different
tracks being used over the same turntable.

When turntables are required for permanent lines, and to sustain heavy
burdens, turntables with a cast iron box are required, constructed on
the principle of the turntables of ordinary railways. The heaviest
wagons may be placed on these box turntables, without any portion
suffering damage or disturbing the level of the ground. In the case of
coal mines, paper mills, cow houses with permanent lines, etc., fixed
plates are employed. Such plates need only be applied where the line is
always wet, or in workshops where the use of turntables is not of
frequent occurrence. This fixed plate is most useful in farmers'
stables, as it does not present any projection which might hurt the feet
of the cattle, and is easy to clean.

The only accident that can happen to the track is the breaking of a
fish-plate. It happens often that the fish-plates get twisted, owing to
rough handling on the part of the workmen, and break in the act of being
straightened. In order to facilitate as much as possible the repairs in
such cases, the fish-plates are not riveted by machinery, but by hand;
and it is only necessary to cut the rivets with which the fish-plate is
fastened, and remove it if broken: A drill passed through the two holes
of the rail removes all burrs that may be in the way of the new rivet.
No vises are required for this operation; the track to be repaired is
held by two workmen at a height of about 28 in. above the ground, care
being taken to let the end under repair rest on a portable anvil, which
is supplied with the necessary appliances. The two fish-plates are put
in their place at the same time, the second rivet being held in place
with one finger, while the first is being riveted with a hammer; if it
is not kept in its place in this manner it may be impossible to put it
in afterward, as the blows of the hammer often cause the fish-plate to
shift, and the holes in the rail are pierced with great precision to
prevent there being too much clearance. No other accident need be feared
with this line, and the breakage described above can easily be repaired
in a few minutes without requiring any skilled workman.

The narrow-gauge system, which has recently received so great a
development on the Continent, since its usefulness has been
demonstrated, and the facility with which it can be applied to the most
varied purposes, has not yet met in England with the same universal
acceptance; and those members of this Institution who crossed the sea to
go to Belgium were, perhaps, surprised to see so large a number of
portable railways employed for agricultural and building purposes and
for contractors' works. But in the hands of so practical a people it may
be expected that the portable narrow gauge railway will soon be applied
even to a larger number of purposes than is the case elsewhere.

* * * * *




GERARD'S ALTERNATING CURRENT MACHINE.


The machine represented in the annexed engravings consists of a movable
inductor, whose alternate poles pass in front of an armature composed of
a double number of oblong and flat bobbins, that are affixed to a circle
firmly connected with the frame. There is a similar circle on each side
of the inductor. The armature is stationary, and the wires that start
from the bobbins are connected with terminals placed upon a wooden
support that surmounts the machine.

[Illustration: GERARD'S ALTERNATING ELECTRIC MACHINE.]

This arrangement allows of every possible grouping of the currents
according to requirements. Thus, the armature may be divided into two
currents, so as to allow of carbons 30 mm. in diameter being burned, or
else so as to have four, eight, twelve, twenty-four, or even forty-eight
distinct circuits capable of being used altogether or in part.

This machine has been studied with a view of rendering the lamps
independent; and there may be produced with it, for example, a voltaic
arc of an intensity of from 250 to 600 carcels for the lighting of a
courtyard, or it may be used for producing arcs of less intensity for
shops, or for supplying incandescent lamps. As each of the circuits is
independent, it becomes easy to light or extinguish any one of the lamps
at will. Since the conductors are formed of ordinary simple wires, the
cost attending the installation of 12 or 24 lamps amounts to just about
the same as it would in the case of a single cable.

[Illustration: GERARD'S 250 H.P. DIRECT CONNECTION ALTERNATING CURRENT
STEAM DYNAMO-ELECTRIC MACHINE.]

One of the annexed cuts represents a Corliss steam engine connected
directly with an alternating current machine of the system under
consideration. According to the inventor, this machine is capable of
supplying 1,000 lamps of a special kind, called "slide lamps," and a
larger number of incandescent ones. - _Revue Industrielle_.

* * * * *




AUTOMATIC FAST SPEED TELEGRAPHY.

By THEO. F. TAYLOR.


Since 1838 much has been done toward increasing the carrying capacity of
a single wire. In response to your invitation I will relate my
experience upon the Postal's large coppered wire, in an effort to
transmit 800 words per minute over a 1,000 mile circuit, and add my mite
to the vast sum of knowledge already possessed by electricians.

As an introduction, I shall mention a few historical facts, but do not
propose to write in this article even a short account of the different
automatic systems, and I must assume that my readers are familiar with
modern automatic machines and appliances.

In 1870, upon the completion of the Automatic Company's 7 ohm wire
between New York and Washington, it happened that Prof. Moses G. Farmer
was in the Washington office when the first message was about to be
sent, and upon being requested, he turned the "crank" and transmitted
the message to New York, at the rate of 217 words per minute.

Upon his return to New York he co-operated with Mr. Prescott in
experiments on W.U. wires, their object being to determine what could be
done on iron wires with the Bain system. A good No. 8 wire running from
New York to Boston was selected, reinsulated, well trimmed, and put in
first-class electrical condition, previous to the test. The "Little"
chemical paper was used.

The maximum speed attained on this wire was 65 words per minute.

About the same time George H. Grace used an electro magnet on the
automatic line with such good effect that the speed on the New
York-Washington circuit was increased to 450 words per minute.

Then a platina stylus or pen was substituted for the iron pen in
connection with iodide paper, and the speed increased to 900 words per
minute.

In 1880, upon the completion of the Rapid Company's 6 ohm wire, between
New York and Boston, 1,200 words per minute were transmitted between the
cities above named.

In 1882, I was employed by the Postal Telegraph Company to put the Leggo
automatic system into practical shape, and, if possible, transmit 800
words per minute between New York and Chicago.

It was proposed to string a steel-copper wire, the copper on which was
to weigh 500 lb. to the mile.

When complete, the wire was rather larger than No. 3, English gauge, but
varied in diameter, some being as large as No. 1, and it averaged 525
lb. of copper per mile and = 1.5 ohms. The surface of this wire was,
however, large.

Dr. Muirhead estimated its static capacity at about 10 M.F., which
subsequent tests proved to be nearly correct.

It will be understood that this static capacity stood in the way of fast
transmission.

Resistance and static capacity are the two factors that determine speed
of signaling.

The duration of the variable state is in proportion to the square of the
length of the conductor, so that the difficulties increase very greatly
as the wire is extended beyond ordinary limits. According to Prescott,
"The duration of the variable condition in a wire of 500 miles is
250,000 times as long as in a wire of 1 mile."

In other words, a long line _retains a charge_, and time must be allowed
for at least a falling off of the charge to a point indicated by the
receiving instrument as zero.

In the construction of the line care was taken to insure the _lowest
possible resistance_ through the circuit, even to the furnishing of the
river cables with conductors weighing 500 lb. per mile.

Ground wires were placed on every tenth pole.

When the first 100 miles of wire had been strung, I was much encouraged
to find that we could telegraph without any difficulty past the average
provincial "ground," provided the terminal grounds were good.

When the western end of this remarkable wire reached Olean, N.Y., 400
miles from New York, my assistant, Mr. S.K. Dingle, proceeded to that
town with a receiving instrument, and we made the first test.

I found that 800 words, or 20,000 impulses, per minute, could be
transmitted in Morse characters over that circuit _without compensation_
for static.

In other words, the old Bain method was competent to telegraph 800 words
per minute on the 400 miles of 1.5 ohm wire.

The trouble began, however, when the wire reached Cleveland, O., about
700 miles from New York.

Upon making a test at Cleveland, I found the signals made a continuous
black line upon the chemical paper. I then placed both ends of the wire
to earth through 3,000 ohms resistance, and introduced a small auxiliary
battery between the chemical paper and earth.

The auxiliary or opposing battery was placed in the same circuit with
the transmitting battery, and the currents which were transmitted from
the latter through the receiving instrument reached the earth by passing
directly through the opposing battery.

The circuit of the opposing battery was permanently completed,
independently of the transmitting apparatus, through both branch
conductors and artificial resistances.

The auxiliary battery at the receiving station normally maintained upon
the main line a continuous electric current of a negative polarity,
which did not produce a mark upon the chemical paper.

When the transmitting battery was applied thereto, the excessive
electro-motive force of the latter overpowered the current from the
auxiliary battery and exerted, by means of a positive current, an


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Online LibraryVariousScientific American Supplement, No. 446, July 19, 1884 → online text (page 4 of 10)