Loading the Material for Transportation.--The material excavated by a
steam shovel is loaded on cars, wagons or carts. On railway work it is
usually loaded on dump or flat cars. On other construction work small
dump cars are most generally used, and sometimes wagons or carts.
[Illustration: Fig. 66.]
[Illustration: Fig. 67.]
[Illustration: Fig. 68.]
[Illustration: Fig. 69.]
[Illustration: Fig. 73.]
Standard gage railway dump cars, Figs. 66 and 67, have nearly gone out
of use. They were replaced by the center ridge flat car, Figs. 68 and
69, and it in turn has been replaced by the ordinary flat car. Dump
cars are of two styles, dumping either by tipping, Fig. 66, or by means
of a hinged sideboard opening on an inclined floor, Fig. 67. Both are
heavy, clumsy, costly and can be used for scarcely any other purpose,
often standing idle from six to eight months of the year. They dump
dry materials very rapidly, but are often slow in discharging damp,
tenacious materials, especially in the hinged sideboard car, whose
floor slope is often not sufficient to permit the material to slip
out quickly, and the material must then be pushed out, thus causing
much delay. The greatest objection to these cars is that they can be
used for scarcely any other purpose, on most railways for no other
purpose; and there is not sufficient work for them to justify keeping
the necessary number on hand for the ordinary work in this line. They
were replaced by the center ridge car, Figs. 68 and 69, as above noted,
which is merely an ordinary flat car with a timber 4 by 6 ins. bolted
on its floor along the center line, serving as a guide for a plow, Fig.
70, drawn over it by the locomotive, thereby unloading the material.
The ridge timber is slightly pointed at both ends to assist in guiding
the plow onto the car as it passes from one car to another. The top
edges of the ridge are sometimes protected by angle irons, as in Fig.
71, and the points by cast iron caps, Fig. 72. By taking off the
center ridge this car can readily be restored to general service after
completing the steam shovel work. The center dump car, shown in Fig.
73, is used only for gravel ballasting where the material is wanted
delivered between the rails.
[Illustration: Fig. 70.]
[Illustration: Fig. 71.]
[Illustration: Fig. 72.]
The brakes are placed on one side of the car, as shown in Figs. 74 and
75. When boulders, loose rock, etc., are to be unloaded, the brake
staff is set in a socket, Fig. 76, and taken out before the plow is
started. This avoids bending or breaking the staff in case any stone
should be wedged between it and the moving plow. Sometimes the socket
is used with the brake at its ordinary place at the end of the car; in
such a case it must always be taken out before the plow reaches it.
The plow, Fig. 70, is built of heavy plate and angle iron, strongly
braced, and headed by a cast steel point, to which the cable is
attached. The sides are curved outward at the bottom, working under the
material and pushing it aside as the plow is drawn along, and held down
on the car by the weight of the material and the partly downward pull
of the cable at its point. Short pieces of old rails and other scrap
iron are also often placed on the plow to help hold it down on the car
when very tenacious materials are to be unloaded. The groove extending
along the center line on the bottom fits over the ridge timber on the
car, and forms the guide by which its movement is directed. Small
stones, protruding bolts, slivered ridge timbers and other obstructions
in the groove of the plow sometimes wedge the point fast, and before
the engine can be stopped, the plow is turned up on its point, and
falling to either side, tumbles off the car. The weight and elasticity
of the cable is often sufficient to draw the plow half a car-length
after the engine has been stopped, and it is often difficult to stop
the plow quick enough to prevent upsetting when obstructions occur,
although the speed is usually only two to three miles per hour. The
unloading nearly always occurs on trestles or embankments, and when
the plow is thrown off the car, its replacement often requires much
time and labor, sometimes even making the services of the wrecking car
necessary. This difficulty is very likely to occur when unloading on
curves, where one side of the point of the groove presses against the
ridge timber. This plow unloads the material equally on both sides of
the car, as it is wanted in filling trestles, raising embankments,
tracks, etc.; but it cannot be used to advantage where the material is
wanted on one side only, as in widening embankments for double track,
side tracks, yards, station grounds, etc.
[Illustration: Fig. 74.]
[Illustration: Fig. 75.]
[Illustration: Fig. 76.]
The many objections to the center ridge car are almost entirely avoided
by the use of the Barnhart plow, Fig. 77, employing the ordinary flat
car without any preparations except changing the brake staffs to one
side or placing them in sockets at their ordinary places and inserting
short stakes in the stake pockets, permitting the immediate use of the
car for general service if necessity should so require. This plow is
also built of heavy plate and angle irons, strongly braced, and headed
by a cast steel point to which the cable is attached; it is preceded
and followed by guiding sleds attached to it by adjustable hinges and
guided over the car by the stakes in the stake pockets, which are
indicated by the dotted lines. The usual speed at which it is drawn
over the car is about four miles per hour, but in loose gravel it can
safely be drawn at a speed of six miles per hour. On straight track
it is scarcely ever thrown off the car unless carelessly handled,
and it works equally well on curves when the usual means are adopted
to maintain a tangential pull of the cable, as will be subsequently
described. Two styles of the Barnhart plow are in use: One unloading
on both sides of the car, and called the center plow, Fig. 77; and the
other unloading on one side only and called the side plow, Fig. 78.
[Illustration: Fig. 77.]
[Illustration: Fig. 78.]
[Illustration: Fig. 79.]
On all but very small pieces of work the cars should be provided with
hinged drop sideboards, Fig. 79, using either of the arrangements shown
in Figs. 80 and 81, which will enable them to carry 12 to 14 cu. yds.
instead of 6 or 7. The side boards are made in two pieces on each side
of the car, Fig. 79. Those shown in Fig. 80 are used for both center
and side plows; they can be quickly dropped by a man walking along the
train, after arriving at the unloading place and striking the hook A an
upward blow with a light hammer. The boards are hooked up again after
the cars have been returned to the steam shovel pit. The side boards
shown in Fig. 81 are used where the side plow only is used. Here the
board on one side only (the unloading side) is hinged (or chained),
and dropped by pulling out the pin B, thus leaving that side of the
car entirely unobstructed for unloading the material; the board on the
other side of the car is bolted to the stake pocket and is not moved.
[Illustration: Fig. 80.]
[Illustration: Fig. 81.]
The cars should also be provided with sheet iron aprons, Figs. 82 and
83, extending from the end of one car onto the floor of the next, to
prevent the material from falling on the track between the cars as the
plow is drawn over them, and delaying the departure of the train until
it can be shoveled out. These aprons are made either in two pieces,
Fig. 82, or in one piece only, Fig. 83. The former are more easily
handled, and permit access to the coupling of the cars without lifting
the apron. Very little material drops on the track when the aprons and
the center plow are used. The single apron is used mostly in connection
with the side plow.
The number of cars and engines required for each steam shovel to keep
it in nearly constant operation depends upon the nature of the material
excavated, the length of haul, and the density of other traffic
upon the main line. This number must be determined by accompanying
circumstances in each case; ordinarily, however, it averages about as
given in Table III.:
TABLE III.
In the steam (--------------On the road up to-------------)
(shovel pit.) 10 miles. 25 miles. 50 miles. 75 miles.
Loco. Cars. Loco. Cars. Loco. Cars. Loco. Cars. Loco. Cars.
Loose gravel 1 30 1 30 2 60 3 90 4 120
Dry clay 1 22 1 22 2 40 - - - -
Damp stiff
clay 1 18 1 18 2 36 - - - -
Hardpan, cemented
gravel, etc.,
loosened
by explosives 1 16 1 16 2 32 - - - -
The length of haul usually ranges from 2 to 15 miles; it seldom
exceeds 25 miles for any material except gravel ballast,
where hauls of 75 miles are frequent, and sometimes reach 200
miles.
[Illustration: Fig. 82.]
[Illustration: Fig. 83.]
[Illustration: Fig. 84.]
[Illustration: Fig. 85.]
On hauls exceeding 25 miles the full number of cars and engines
required can seldom be obtained, and the output of the
steam shovel is correspondingly decreased. The delay in returning
empty cars due to detentions from other trains is the
great trouble most keenly felt in steam shovel work on railways
in operation. The so-called "mud train" is generally considered
an outcast, and is usually the last train to receive the dispatcher's
attention for an order to the road. These delays are
daily occurrences, and it is quite an exceptional case when the
machine is amply supplied with empty cars. The record of
most steam shovels on such work is therefore a rather poor one,
when the machine really made a good showing for the crippled
condition of its car service. Some of these delays can be
avoided or shortened by stationing a telegraph operator at the
outgoing end of the pit, and on all but very small pieces of work
his wages will be many times balanced by the time gained in
keeping the whole plant moving, by obtaining train orders
quicker, and remaining constantly informed of the whereabouts
of the construction and other trains, and regulating the work in
the pit accordingly.
For general construction work where the excavated material
is not loaded on standard gage railway cars, small dump cars,
Figs. 84 and 85, are generally used. They are more economical
than wagons or carts, which are employed only in special
cases, mostly in cities, where the material must be hauled some
distance over several intersecting streets, and where a track will
not be allowed; or for very small jobs with a long haul which
would not justify building a track.
The gage of these tracks is usually 2-1/2 or 3 ft., sometimes
2 ft. or even 1-1/2 ft. only; the latter gages are not often used,
and the 3-ft. gage is usually preferred.
The rails most generally used weigh 20 lbs. per yd. Although
these tracks are only temporary their construction should
be fairly substantial; but they are often built in an exceedingly
careless and insecure manner, causing a great waste of power
in pulling the cars over them, and resulting in frequent delays,
due to derailments. The grade is usually arranged so that the
loaded cars will run downhill by gravity, and only the empty
cars need be drawn back to the pit. On small work, horses or
mules are used to pull the cars, but on large jobs small locomotives
are employed. Small dump cars vary in capacity from
1 to 3 cu. yds., the latter size being most generally used. The
side dump car, Fig. 84, dumps on either side. The rotary dump
car, Fig. 85, unloads on either side or end; the box can be
turned around horizontally, revolving about a vertical pin in a
turntable on the frame; they are used mostly in dumping off the
end of a fill.
In making fills it is nearly always the best plan to build a
temporary trestle of round pieces of beech, cottonwood or other
cheap trees, old bridge or building timber, or other second-class
lumber, and then filling in with the side dump cars. By adopting
this plan the unloading will progress much more rapidly
than by dumping from the end of a fill, where only one car at a
time can be unloaded. These trestles are inexpensive, and the
saving in labor and time in making the fill will amply repay
their cost.
[Illustration: Fig. 86.]
[Illustration: Fig. 87.]
[Illustration: Fig. 88.]
[Illustration: Fig. 89.]
Unloading the Material.--On railways the unloading is seldom
done by slow and expensive hand labor with the shovel;
sometimes dump cars are employed, but in most cases flat cars
and the plow are used. The trains consist of 10 to 30 cars. The
car carrying the plow is attached to the rear of the train at the
nearest side track to the unloading place, if it is not over 10
miles from the steam shovel pit this car is generally carried
back and forth to avoid an extra stop to couple it on the train
at the side track. One end of a steel wire cable is then hooked
to the plow and the other end (which is attached to an ordinary
car coupling link) coupled to a car or the engine. Usually this
cable is about 400 ft. long and extends over 12 cars. The
brakes on these cars are then set up tight and the engine started
with the forward cars, Fig. 86. In very tenacious or partially
frozen material the rear cars are sometimes pulled along by the
plow; the wheels are then blocked with pieces of wood or with
stones; sometimes it is even necessary to chain a few of these
cars to the track to prevent the rear lot of cars from moving.
After the plow has been started, it is drawn along slowly until
it arrives on the last car, Fig. 87. The engine is then stopped
and backed up a few feet to permit the cable to be thrown on
one side of the track, Fig. 88. The train is then backed up
again and coupled to the unloaded cars, when four to six men
throw the cable on the next loaded cars, Fig. 89, coupling its
forward end to a car or to the engine if the cable is long
enough. The operation is then repeated until all but the car
next to the engine is unloaded; this car carries the plow and is
the first car to be unloaded by the next train. The ends of the
cable are then detached from engine and plow, thrown to one
side of the track, and left there for the next train to pick up
and use in the same manner.
[Illustration: Fig. 90.]
[Illustration: Fig. 91.]
When filling a trestle the cable cannot be thrown on one
side, as described, but must be unhooked from the plow (the rear
lot of cars being left standing on the trestle), dragged across
the trestle, and there thrown to one side. The forward lot of
cars is then backed up until its rear car is opposite the rear end
of the cable, when it is loaded, the train backed up, coupled and
unloaded, as before described. After unloading the train the
cable must again be dragged beyond the trestle, and there
thrown to one side of the track and left for the next train. The
time required for unloading varies from 10 to 30 minutes, depending
upon the nature of the material and the number of
cars, and averages about 20 minutes, doing as much work
in that time as 20 men can do in a day.
When unloading on curves the operations are delayed by
the necessity of using snatch blocks on the cars to insure a nearly
tangential pull of the cable and avoid pulling the plow off the
car. These blocks are applied as shown in Fig. 90, and at A,
Fig. 91. They are hooked to long chains extending over the
car and fastened to the bolster or arch bar of the truck. The
number of snatch blocks required depends upon the degree of
the curve and the length of the cable; generally four to six
blocks, one to every third car, are enough. As the plow approaches
one of these blocks it must be stopped, block and
chain removed and transferred forward for use at that end of
the train. The other operations of unloading are the same as
when on straight track. The time required in unloading on
curves varies from 20 minutes to an hour, and averages about
40 minutes, doing as much work in that time as 20 men can do
in a day.
The steel wire cables used vary from 1 in. to 1-1/2 ins. diameter.
The former are used for unloading loose gravel and
sandy material; they are light and easily handled, but cannot
bear much jerking. The most usual size is 1-1/4 ins. diameter.
Heavier cables require too many men (six to eight) to load them
on the car preparatory to starting the plow.
One of the heaviest locomotives on the road (preferably one
of the consolidation type) should be used for drawing the plow
over the cars. These engines are generally able to keep the
plow moving with a strong steady pull, avoiding the necessity
of taking a run to start the plow, and all injurious jerking of
the cable, which frequently breaks it. For tenacious materials
and where the haul is not more than 25 miles, it is often good
policy to keep one heavy engine at this work, the other engines
merely hauling the trains; this can generally be arranged so that
no more engines are used than if each engine were to unload
its own train. Sometimes two light engines are used for this
purpose, but they can seldom move in perfect unison and more
or less jerking is the result. Unfortunately the engines for the
"mud trains" are not always in the best working order; they
are mostly those which are about to go into the shops for turning
down the tires or for general repairs, and are not in fit
condition for general traffic, but still considered good enough
for this service. Expensive delays due to badly working engines
are frequently the result.
The locomotive in the steam shovel pit should always be
equipped with a steam or air driver brake to assist in quickly
stopping the cars at exactly the right place when setting them
for loading by the steam shovel. For the same reason the
brakeman should be allowed to use short sticks in the brake-wheels
to obtain a greater leverage in turning them.
Both engine and train crews should be changed as little as
possible and they should retain their respective trains in the pit
on the road or at the dump. Most of the men dislike the "mud
train" service, but some (especially the older ones) are glad to
get a steady job with a full night's rest, and these are the men
to be chosen. They take an interest in the success of the work,
and soon acquire an expertness in handling cars, plows, etc.,
that makes them worth twice as much as the inexperienced or
unwilling ones. The wages of these men should be equalized
to average the same as the men on the road in other service,
otherwise dissatisfaction and indifference are sure to result.
[Illustration: Fig. 92.]
The machine shown in Fig. 92 has lately come into use for
pulling the plow over the cars to unload them. This is merely
a double cylinder (10 by 12 ins.) reversible hoisting engine,
resting on a heavy cast iron bedplate attached to the floor of a
box car. Steam is supplied to the engine from the locomotive
of the train, which is coupled to this car when the unloading is
to begin. With this machine there is no injurious jerking of
the cable, and consequently very little breakages or delays, and
heavy loads of 15 cu. yds. of tenacious material are readily
plowed off the cars in a more satisfactory manner than can be
done by any one or two locomotives. Blocking the wheels or
chaining cars to the track need not be resorted to; the cars cannot
move, for the machine pulls the plow toward itself and the
strain is resisted by the cars between them. If it is desired to
scatter small quantities of material along the track, as it is often
wanted in surfacing or raising track, both plow and train are
moved in the same direction at the same or varying speeds, as
may be necessary to unload the required amount of material.
If a large quantity of material is wanted within a short distance,
as usually happens on washouts, train and plow are moved in
opposite directions. By moving them in this manner at the
same speed, a whole train can be unloaded at any desired spot.
Where two locomotives must be used to pull the plow over the
cars, the use of this machine will dispense with one of them,
and do the work in half the time. On large jobs it should not
be missing. The cable is wound around the drum, A, Fig. 92,
and must be long enough to extend over the whole length of
the train. A steel wire cable 1-1/8 ins. diameter is generally
used; but for loose gravel a 1 in. cable is amply strong enough.
The steam shovel can be operated continuously throughout
the year in all kinds of weather, though operations are often suspended
in extremely cold weather. When working in cold
weather the face of the bank sometimes freezes during the night
to the depth of 3 to 6 ins., but this crust is easily broken in the
morning by a few small charges of powder, and then the material
can be excavated as easily as at any other season.
[Illustration: Harris & Carter
Spreader.
Fig. 93.
Fig. 94.]
In freezing weather the floors of the cars should be sprinkled
with brine just before loading; the brine is kept in barrels at the
head of the machine, and one man using an ordinary garden
sprinkling can is detailed for the work. This prevents the material
from freezing to the floor of the car for three to four
hours, and allows it to slip off readily when the plow is put in
operation. No train should be left standing over night without
unloading. The brine will not prevent freezing for this length
of time, and to unload one car of the frozen stuff requires a day's
labor of four to six men.
Distributing the Material After Unloading.--In widening
embankments for side tracks, double track, yard and station
grounds, etc., the material is unloaded, as described above, forming
a ridge on both sides of the track if unloaded with the
center plow, or on one side of the track only if unloaded with the
side plow. This material is sometimes leveled off by hand, a
very slow and expensive job, but generally it is done with a leveler
or spreader, Figs. 93 to 96.
[Illustration: Edson
Spreader.
Fig. 95.
Fig. 96.]
In the Harris & Carter spreader, Figs. 93 and 94, the car
body is cut away between the trucks to receive the two wings
which level or spread the material. One or both wings can be
used, and they can be raised and lowered to adjust them to any
height of new embankment wanted. They will spread the material
for a distance of 3 ft. from the rail. When shipping the
spreader over the road the wings are drawn up by a hand windlass,
revolving about hinges fixed to the braces under the floor
of the car, as shown in Fig. 94. In this position the clearance
is the same as that of an ordinary passenger car.
The Edson spreader, Figs. 95 and 96, has only one wing,
attached to an ordinary flat car, and arranged to raise and
lower to adjust it to any height of new embankment wanted.
The wheel, A, bears against the head of the rail, forming a brace
where one is most needed, and greatly assists in preventing a
derailment when hard or tenacious materials are suddenly encountered.
The wing, braces, windlass, etc., are so constructed
that they can be readily removed from the car, thereby restoring
it to general service on completion of the work in hand. This
spreader is used mostly in connection with the side plow; it will
level the material for a distance of 15 ft. from the rail, wide
enough to permit laying a side track from which the embankment
can be further widened. Only one side at a time can be
widened with this spreader. If it is desired to widen the embankment
on both sides of the track, one side is completed first;
the cars and spreader are then turned around on the nearest
turntable or Y-track, and the other side widened by drawing
the spreader in the opposite direction. If the cars are not provided
with aprons they need not be turned around. This
spreader is generally arranged to cut about 6 ins. below the
bottom of the ties of the main track, thereby forming the subgrade
for the side track, and maintaining proper drainage of
the main track. The apron, B, is bolted on the spreader, and
serves to remove any loose material which may fall on the
track between the rail and the ends of the ties. When shipping
the spreader over the road, Fig. 96, it is drawn up by a hand
windlass revolving about hinges on the side sill of the car and
folded down on it; in this position it will clear anything that
other cars can pass.
The cars of both styles of spreaders are loaded with old rails,
frogs, scrap iron, etc., to hold them down and prevent derailments
when hard or tenacious materials are suddenly encountered.
Loads of five to ten tons are generally sufficient, though
loads up to 15 tons are sometimes required.
Spreaders are usually drawn at a speed of six to eight miles
per hour; in loose gravel the speed often reaches 10 miles per
hour. They will level off a ridge a mile in length in six to
ten minutes, doing as much work in that time as 100 men can do
in a day.
The spreader is usually stationed in the nearest side track to
the unloading place. Frequently it can be hauled between this
track and the dump without raising it, or raising it only partially
to clear depot platforms, switch stands and other obstructions
and thereby avoid the necessity of folding it down on the
car while passing between these points.
Ordinarily the spreading is done by the last train before the
close of the day. In cold weather or on short dumps it must
be done oftener; either to prevent freezing, or to make room for
the unloading material which would otherwise pile up too high
for easy spreading, or be liable to roll back on the track and
obstruct it for the next train. In using the spreader it is coupled
to the rear of the car carrying the plow, and after the train has
been unloaded it is pulled over the length of the ridge of material
unloaded from its own and preceding trains, as shown
in Figs. 97 and 98.