STEAM SHOVELS
--AND--
STEAM SHOVEL WORK.
By E. A. HERMANN, M. Am. Soc. C. E.
1894.
ENGINEERING NEWS PUBLISHING CO.,
NEW YORK.
Copyright. 1894, by Engineering News Publishing Co.
CONTENTS.
Pages.
PART 1.--Steam Shovels 1-19
" 2.--Steam Shovel Work 19-41
" 3.--Disposition of Material 41-55
" 4.--Cost of Steam Shovel Work 55-57
INDEX.
Ballast, plowing, 48
Blasting, 39, 52
Brine, sprinkling earth, 52
Cars, dump, 19, 41, 47
Flat, 42
Loading, 19
Unloading, 42, 47
Cost of work, 55
Cuts, 28, 36, 39
Time for, 17
Widening, 19
Explosives, 39, 52
Fills, trestles for, 47
Grades, construction track, 34
Cutting down, 28
Grading, 25
Gravel train, 42, 45, 50
Engines for, 50
Unloading, 48
Leveling, 53
Loading cars, 19
Gangs for, 21, 22, 23
Operating, men for, 18
Plow, Barnhart, 43
Gravel, 42
Plowing, cable for, 50
Gravel train, 48
Hauling engine for, 51
Winter, brine for, 52
Railways, construction, 33
Reducing grades, 28
Widening cuts, 19
Railway work, 18, 28, 33
Rapid unloader, 51
Spreaders, 53
Steam shovels, Barnhart, 6
Boilers, 9
Bucyrus, 4
Clement, 10
Daily capacity, 41
Description, 5
Giant, 12
Invention of, 1
Little Giant, 12
Industrial Works, 10
Machinery of, 5
Marion S. S. & Dredge Co., 6
Number of men, 18
Operation, 16
Osgood, 2
Otis-Chapman, 14
Repairs, 19
Souther's, 14
Thompson, 4
Toledo F. & M. Co., 8
Types, 3
Victor, 8
Vulcan Iron Works, 12
Tools, 16, 18
Track, arrangement of, 19
Narrow gage, 47
Trains, dirt, handling, 19, 42, 45, 48, 50
Trestles for fills, 47
Widening cuts, 19
STEAM SHOVELS AND STEAM SHOVEL WORK.[1]
[Footnote 1: Copyright by Engineering News Publishing Co., 1894.]
By E. A. HERMANN, M. Am. Soc. C. E.
Part I.--Steam Shovels.
The following article originated in a short paper which was read before
a local society of civil engineers, and there were so many requests
made for this paper and the illustrations presented with it that the
author was led to believe that there was a demand for such information.
Believing that a better understanding of the capabilities of these
machines will serve a useful purpose in economizing money, time and
labor in the execution of work to which they are adapted, the author
presents in this article the information learned by a long practical
experience in this special class of work. Descriptions of the various
steam shovels can readily be found in the trade catalogues of the
different manufacturers, but very little has been published on the
manner of using them in the execution of different classes of work, and
the disposition of the excavated material after it has been loaded on
cars or wagons. This part of the subject will receive most attention,
and although much of it may seem very elementary to those who have had
an extended experience in operating steam shovels, it may be entirely
new to the much larger number who have had few or no opportunities for
doing work of this kind. It has been the aim of the author to condense
the reading matter as much as possible, making it a point to use many
illustrations in place of lengthy explanations, thus presenting the
subject more clearly than by extended descriptions.
[Illustration: FIG. 1. ELEVATION AND HALF PLAN OF OSGOOD STEAM SHOVEL;
Osgood Dredge Co., Albany, N. Y.]
The steam shovel, or steam excavator, is a modified form of dredge
adapted for excavating material on dry land. It was designed and
patented by a Mr. Otis, about 1840, and like most new inventions the
first machine built was a very clumsy affair, but even in this
crude state it possessed many advantages for removing large masses
of material. Its merits were recognized in its earliest stages, and
with increased experience in its operation improvements were soon made
which rendered it almost indispensable on all works requiring large
quantities of excavation.
It was not until 1865, however, that the machine came into general use.
About this time the largely increased railway construction created an
active demand for the steam shovel, which demand was quickly supplied
by several manufacturers, whose machines vary in distinctive designs of
various parts, but the principles of operation are essentially the same
in them all.
Types of Steam Shovels.--There are three types of steam shovels: First;
machines mounted on trucks of standard gage, transported from place to
place in freight trains (or propelled by their own power), and intended
for railway work only. Second; machines mounted on wheels of other than
standard gage, transported in sections by boat or wagon, or loaded
complete on flat cars, and intended for both railway and other work.
Third; machines mounted on wheels fitted for transportation over common
roads, propelled by their own power, and intended for railway and other
work.
The first machines built were of the second type. As now constructed
they are mounted on a wide wooden frame or car body, supported by
four small wheels of 7 ft. to 8 ft. gage, thus placing the machinery
close to the ground, with a wide base of support. In transporting this
machine from one place to another, not on the line of a railway, it is
necessary to take it apart, forward the sections and put them together
again at the site of the new work. The machine is built with a view
to rapid dismantling and re-erection, and for work requiring a large
machine for economical excavation, located in hilly country not yet
made accessible by rail, or requiring transportation by boat, it is
the machine most generally used. Its ready adaptability to all kinds
of work in any location has made it the favorite machine with many
general contractors whose work includes large contracts for railway
and other excavation. For transportation by rail this machine is run
onto an ordinary flat car, only the crane being detached and loaded on
a separate car. With this manner of shipment the machine can be made
ready for railway work very quickly, but for exclusive railway work
a machine of a later design has come into use and is now generally
preferred for this class of work.
[Illustration: FIG. 2.--THOMPSON STEAM SHOVEL; Bucyrus Steam Shovel &
Dredge Co., South Milwaukee, Wis.]
This is the machine of the first type, resting on a wooden or iron car
body, supported on trucks of standard gage, with an iron or steel crane
from 18 to 26 ft. high over the track when in working order, and which
can be lowered to 14 ft. to permit shipment through tunnels and under
low overhead bridges.
Machines of the third type are generally of smaller capacity than the
others; they have come into general use only within the past few years,
but are now multiplying rapidly in numbers as their utility for nearly
all kinds of work is better appreciated. They are especially adapted to
smaller jobs and work not readily accessible by rail, but where common
roads are available.
These three types are shown in Figs. 1 to 9, representing the machines
of seven of the principal manufacturers.
Steam shovels will excavate any kind of material except solid rock,
and they will load rock if it has been broken up by explosives into
pieces of not more than 3-4 cu. yd. in size. The materials excavated
by them are mostly sand, loose gravel, all kinds of clay, cemented
gravel, hardpan, clays mixed with bowlders and other small stones, ore,
phosphate rock, loose rock and thin seams of slate, shale or sandstone.
These machines are used for excavating material, loading it on cars or
wagons for ballasting tracks; for filling trestles, streets, roads,
dams, lots and new city additions; for widening embankments for double
track, side tracks, yards, shops and station grounds; for cutting down
street, road and railway grades; grading lots and new city additions,
railway yards, shop and station grounds; widening cuts, removing land
slides, stripping coal fields, ore beds and stone quarries; digging
canals and drainage ditches, loading clays for brick yards, etc.
Construction of Steam Shovels.--The general plan of construction of
the machines, shown in Figs. 1 to 9, is essentially the same in all,
and consists of a strong frame, mounted on wheels, forming the base
to which all working parts are attached. The boiler and machinery are
placed near the rear end of the frame, and the mast, or post, and crane
at the front end. The crane is made in two pieces connected only at
the top or point, and at the foot of the mast. Between these pieces,
serving as guides, is the dipper handle, carrying at its farther end
the dipper or scoop. To the top of the post (or to the foot in some
machines) the swinging circle is secured.
[Illustration: FIG. 3.--BARNHART STEAM SHOVEL; Marion Steam Shovel Co.,
Marion, O.]
The most used, and hence the most important part of the machinery of
the steam shovel is the gearing imparting motion to the hoisting drum,
actuating the chains by which the dipper is raised and lowered. It is
in almost constant use, and is often subjected to severe shocks in hard
digging. Of all parts of the machinery it is the most likely to break
or rapidly wear out. Naturally it has received the most attention of
any part of the steam shovel in all efforts to improve the design,
strength and durability of the machine. There are a number of different
gears in use, and essentially they are either friction clutches or
positive gearing. The use of the former subjects the machinery and
crane to less severe shocks, and can be thrown in and out of gear more
rapidly, but it wears out quicker, often causes delay by heating, and
requires frequent repairs. Positive gearing exposes the machinery
and crane to more severe shocks in hard digging, and must be started
slower, especially in hard material, but while these machines are a
little slower than those operated with friction clutches, they are less
subject to the expense of repairs and delay due to the disarrangement
of the hoisting gear, so that their total output of material about
equals, and sometimes exceeds, the quicker moving friction gear machine.
The mechanism for thrusting the dipper into the bank is attached to the
crane, and the forms most generally used are as follows:
1. A chain, one end of which is attached to the rear end of the dipper
handle, and the other end wound around a drum receiving its motion by
an endless chain passing over a sprocket wheel connected to the axle
of the sprocket wheel at the top of the mast, over which the hoisting
chain passes, thereby revolving both wheels. This drum is thrown into
gear by a friction clutch, and its motion regulated by the cranesman's
lever and footbrake.
2. A rack on the dipper handle operated by a pinion attached to a shaft
revolved and regulated as above described.
3. A small double cylinder engine operating either a pinion and rack as
above described, or revolving a drum with a chain attached to it, and
the rear end of the dipper handle as described in the first case.
4. A long steam cylinder attached to the dipper handle, whose piston
rod is connected to the dipper, extending or withdrawing it as desired.
[Illustration: FIG. 5.--VICTOR STEAM SHOVEL; Toledo Foundry & Machine
Co., Toledo, O.]
The thrusting mechanism used in the last two cases imparts a rapid,
steady and powerful motion, but the extra engines or steam cylinder and
their connecting steam pipes involve a complication which often more
than balances their advantages.
Swinging the crane in a horizontal direction is generally accomplished
in one of the following three ways:
1. A chain passing around the swinging circle attached to the post,
and wound around drums connected to the engine by positive gearing or
friction clutches.
2. A wire rope passing round the swinging circle and connected to the
piston rods operated by two long steam cylinders.
3. A chain passing round the swinging circle and wound around a drum
connected to a small reversible engine.
The mechanisms used in the last two cases have the same advantages,
but also suffer from the same objections urged against employing small
engines or a steam cylinder for thrusting the dipper into the bank.
The engines are either of the upright type with a single steam
cylinder, or of the horizontal type, with double horizontal steam
cylinders. The size of the cylinders varies for machines of different
capacities, ranging from 8 by 10 ins. to 10 by 12 ins. for the upright
engines, and 6 by 8 ins. to 13 by 16 ins. for the horizontal engines.
The upright type of boiler with submerged flues is usually preferred,
as it occupies only a small space. Horizontal boilers of the locomotive
type are used in a few machines, and are more economical in the use of
fuel, but occupy too large a floor space. Forced draft is used in both
types of boilers, and they are generally worked to the limit of their
capacity. The usual working pressure is 90 lbs. per sq. in. The safety
valve is generally set to blow off at 120 lbs. per sq. in. The boiler
is supplied with water either from an upright circular sheet iron tank
located in a corner of the machine, behind the boiler, or from a sheet
iron box tank hung under the floor. These tanks usually hold about
1,000 gallons of water, enough to run the machine half a day. The water
is obtained by a pump or siphon from the tender of a locomotive on
railway work, or is hauled to the machine by wagon on other work.
[Illustration: FIG. 6.--CLEMENT STEAM SHOVEL; Industrial Works, Bay
City, Mich.]
In some machines the frame or car body is made of wood, generally
oak, often incased with heavy plate iron. In others it is constructed
of iron or steel I-beams and channels. In all machines it is strongly
built and braced with a view to sustain the weight of the working parts
and to resist the shocks to which it is subjected. The floor is usually
of 3-in. oak plank.
The mast or post is made of cast or wrought iron, strongly braced and
guyed to the frame. It is the pivot about which the crane swings, and
easy working in its bearings is of great importance for the rapid and
economical operation of the machine. In order to prevent breakage or
delay it should never be permitted to wabble by neglecting to promptly
tighten its braces and guys in case they should work loose. The
post should always stand vertical, or practically so, to insure the
horizontal motion of the crane and avoid unnecessary straining of the
swinging gear. For this reason the machine should be set practically
level before beginning operations; and using a small mason's level is
better than trusting to the eye, when blocking under the track and
adjusting the jack screws for this purpose.
The crane is secured to the post, and is made of wood, iron or steel,
strongly and compactly built to resist the shocks to which it is often
subjected. It is from 14 to 20 ft. high above the track or ground,
varying with machines of different sizes and manufacture, and swings
horizontally through an angle of 180 to 240 degrees, with a radius of
15 to 20 ft. In some machines it must be detached from the post for
shipment, in others (mostly those made for railway use exclusively)
it can be lowered to a height of 14 ft. above the track, thereby
permitting shipment without detaching from the post.
The dipper, scoop, or bucket is made of iron or steel, shaped somewhat
like a coal scuttle. Its cutting edge is protected by four teeth
made of steel or steel pointed. These teeth are easily removed for
sharpening or replacement. Dippers vary in size from 1/2 cu. yd. to
2-1/2 cu. yds. capacity. They also vary somewhat in shape, according
to the material to be excavated, though no special provision is made
for this unless there are very large quantities of the same kind of
material to be removed; or for machines working in a certain class
of material only, like ore loaders. For general work in all kinds of
materials the dipper is seldom changed.
For soft, tenacious material, likely to adhere to the inner sides of
the dipper, and not drop out promptly when the bottom door is opened
for unloading, the dipper is shaped as shown in Fig. 10, with a larger
bottom than mouth. In hard, or dry soft material the section shows
parallel sides, as in Fig. 11. For general use the bottom of the dipper
should be slightly larger than the mouth, as most materials contain
more or less moisture which is likely to produce a partial clogging of
the dipper by material sticking to the inner sides, especially between
the teeth, necessitating frequent cleaning out whenever the machine is
stopped while preparing to move forward, and sometimes oftener. For
ordinary clay, cemented gravel, and hard dry materials, a dipper with
a wide and shallow mouth, as shown in plan in Fig. 12, is preferred
to the one shown in Fig. 13, which latter is better adapted for loose
gravel, sand and other soft dry materials where a deep cut can easily
be made. For hardpan, shale, loose rock and similar materials, ample
strength of teeth and dipper is of greater importance than its shape.
[Illustration: FIG. 7.--GIANT STEAM SHOVEL; Vulcan Iron Works Co.,
Toledo, O.]
[Illustration: FIG. 8.--LITTLE GIANT STEAM SHOVEL; Vulcan Iron Works
Co., Toledo, O.]
To prevent tenacious material from sticking to the inner sides of the
dipper, and to allow it to drop out freely when the bottom door is
opened, it is often good economy to place a barrel of water near the
head of the machine from which a bucketful can be taken and thrown into
the dipper just before each cut. The water acts as a lubricant and
causes the material to drop out more readily. For cleaning the dipper,
the tool shown in Fig. 14 is used.
[Illustration: Fig. 10.
Fig. 11.
Fig. 12.
Fig. 13.
Figs. 10 to 13.--Buckets for Steam Shovel.]
The chains have links of three-quarters-inch to one-inch diameter, and
are made of iron, sometimes of steel. Their constant use necessarily
subjects them to great wear, and as they are also often exposed to
severe shocks (especially the hoisting chain) they must be made of the
very best material and in the most careful manner. At present iron
chains are preferred to those made of steel: they are more durable, and
less likely to break under severe shocks. Steel chains have suffered in
reputation through rapid wear and frequent breakages occurring within
the last few years, but with increased experience in their manufacture
and use they will undoubtedly be improved, and eventually take the lead
over iron chains.
The propelling mechanism consists of an endless chain connecting one
or more axles of the truck or supporting wheels with the shaft of the
hoisting drum by means of friction clutches or positive gearing. The
usual speed is five to six miles per hour.
[Illustration: FIG. 9.--OTIS-CHAPMAN STEAM SHOVEL; John Souther & Co.,
Boston, Mass.]
Steam shovels of seven of the most prominent manufacturers are shown
in Figs. 1 to 9, and the general particulars of each are given in
condensed form in Table I. In each case the boiler is upright.
TABLE I.--GENERAL DESCRIPTION OF THE IMPORTANT PARTS OF THE MOST
PROMINENT MAKES OF STEAM SHOVELS.
+---Frame------+
Fig. Size, Running Gage, En- Cylin- H'st'g
Shovel. Material. ft. gear. ft.ins. B'l'r gine der, gear.
ins.
1. Osgood Wood 10 × 34 2 trucks 4 8-1/2 V H 2 10 ×12 F
" " 10 × 30 " " " " " 8-1/4×10 F
" " 10 × 25 " " " " " 7 ×10 F
2. Thompson {I-be'm} 10 × 32 " " " " " 10 ×14 F
" {and } 10 × 30 " " " " " 8 ×12 F
" {chan- } 10 × 28 " " " " " 8 ×10 F
" {nels } 10 × 24 " " " " " 6 × 8 F
3. Barnhart " 10 × 28 " " " V " 8 ×10 F
" " 10 × 26 " " " H 1 8 ×10 F
" " 10 × 24 " " " V " 8 ×10 F
" " 10 × 22 " " " " " 6 × 8 F
5. Victor " 10 × 30 " " " H 2 8 ×10 F
6. Clement " 10 × 30 " " " " " 8 ×10 P
7. Giant " 10 × 35A " " " " " 13 ×16 F
" " 10 × 35 " " " " " 8 ×12 F
" " 10 × 30 " " " " " 7 ×11 F
8. Little Giant " 7 × 23{4 r'd wh 8 0 " " " 7 ×11 F
" " " 6 × 23{ " " 8 0 " " " 6 × 8 F
9. Otis-Ch'pm'n Wood 10 × 22{4 fl'ge wh 7 10 " V 1 10 ×12 P
" " 10 × 18{ " " 7 10 " " " 8 ×10 P
Transcriber's Note:
Boiler and Engine--V=Vert., H=Hor.
Hoisting Gear--F=Friction Clutch, P=Positive
Fig. Thrusting Mechanism. Swinging Mechanism.
{ Reversible engines, 2 steam cylinders }
1. { each 6 × 8 ins. } Chains attached to
{ Do., do 5 × 6 ins. } circle geared
} to hoisting drum
2. { Rack on dipper handle actuated by }
3. { friction clutch geared to hoisting drum. }
5. { Reversible engine, }
{ 2 steam cyls. 6 × 8 ins. } Wire ropes attached to
} circle and pist'n rods
6. { Long st'm cyl., } in long st'm cyl.
{ piston rod at'ch'd to dipper }
{ Reversible engine, } Reversible engine,
7. { 2 steam cyls. } 2 steam cylinders
{ 5 × 6 ins. } 5 × 6 ins.; except A,
8. { } cylinders 7 × 9 ins.
{ Chains on dipper handle actuated } Chains attached to
9. { by friction clutch geared } circle geared to
{ to hoisting drum. } hoisting drum
+--------------Crane.------------+
| +--H'ght ab've--+ |
gr'nd or track. Capacity
Working Shipping Swinging of
Post order, order, Radius, angle, dipper, W'ht,
Fig. material. Material. ft. ft. ft. deg. cu. yds. tons.
1. {Wt. iron} Wt. iron 26 14 24 240 2 40
{ A } " 24 14 24 240 1-1/2 30
{ frame } " 20 14 20 240 1 20
2. {Cast iron " 23 14 20 200 2-1/2 45
{ " " 18 14 18 200 1-3/4 40
{ " " 18 14 16 200 1-1/4 30
{ " " 16 14 12 200 3/4 20
3. {Wt. iron Wood 26 14 20 200 1-1/2 37
{ " " 24 14 20 200 1 26
{ " " 20 14 18 200 3/4 16
{ " " 18 14 18 200 1/2 12
5. {Hollow Wt. iron 19 14 20 200 2 40
{wt. ir.
6. {Cast iron " 20 14 20 200 2 40
7. {Cast steel Steel 20 14 19 200 2-1/2 70
{Cast iron " 20 14 19 200 1-3/4 45
{ " " 18 14 17 200 1-1/4 30
8. { " " 16 Detach'd 15 185 1-1/4 20
{ " " 15 " 15 185 3/4 18
9. { " Wood 20 " 20 200 2-1/2 26
{ " " 16 " 18 200 1-1/4 15
Makers: 1 (Osgood): Osgood Dredge Co., Albany, N. Y. 2 (Thompson):
Bucyrus Steam Shovel & Dredge Co., Bucyrus, O. 3, 4 (Barnhart): Marion
Steam Shovel Co., Marion, O. 5 (Victor): Toledo Foundry & Machine Co.,
Toledo, O. 6 (Clement): Industrial Works, Bay City, Mich. 7 (Giant) and
8 (Little Giant): Vulcan Iron Works Co., Toledo, O. 9 (Otis-Chapman):
John Souther & Co., Boston, Mass.
Operation of Steam Shovels.--All movements of the steam shovel are
controlled by two men, the engineman and the cranesman. The former is
stationed near the engine, the latter on a small platform attached to
the crane. The engineman directs the movements for raising and lowering
the dipper, swinging it into position for unloading, and moving the
machine forward or backward. The cranesman regulates the depth of the
cut made by the dipper, releases it from the bank when full or near the
top of the crane, and pulls the spring latch of the bottom door of the
dipper when in position for unloading, thereby dumping its contents.
[Illustration: Fig. 14.--Spade for Cleaning Buckets.]
These motions are shown in Figs. 15 and 16. Beginning with the dipper
in the position shown at A, Fig. 15, the engineman throws the hoisting
drum into gear, and starting the engine pulls the dipper upward, the
cranesman at the same time thrusting it forward, regulating the depth
of the cut so that it will not stop the engine or tip up the rear
end of the machine. When the dipper has reached the position B, near
the top of the crane, the engineman throws the hoisting drum out of
gear, and holds it in position with a foot brake; at the same time
the cranesman by easing his foot brake, allows the dipper to fall
back to the position C. The engineman then swings the dipper over the
car or wagon, as shown in Fig. 16, when the cranesman pulls the latch
rope, thereby opening the bottom door of the dipper and dropping the
contents. The engineman then swings the crane back again to the next
cut, at the same time releasing his foot brake on the hoisting drum
until the dipper has fallen to a point near the ground, as at D, Fig.
15, where he holds it for an instant with the foot brake, then drops it
by releasing the brake, while the cranesman (during this slight drop)
regulates the length of the radius of the dipper handle by releasing
his foot brake so as to bring the dipper into the position A again, and
adjoining the last cut. While the dipper is being lowered, the bottom
door closes and latches itself by its own weight, when all is ready
again for another cut.
These motions are very simple when taken separately, but when performed
together by two different men, experience and quickness in both are
required to carry on the work rapidly and harmoniously, without
breakages or delays. In loose gravel one cut can be made in a half to
three-quarters of a minute; in hard materials one and a half to two
minutes, seldom more.
[Illustration: Fig. 15.--Showing Series of Operations for Excavating.]
[Illustration: Fig. 16.--Loading Earth from Steam Shovel Onto Cars.]
After all material within reach of the dipper has been removed, an
unoccupied section of track (generally about 4 ft. long) at the rear
of the steam shovel is attached to the dipper by a chain and dragged
around the machine to the front (by swinging the dipper horizontally)
and there placed in position in line with the sections of track under
the machine. The screws at the ends of the jack arm (a horizontal bar
at the front end of the machine used for steadying it when cuts are
taken at right angles to the steam shovel) are then released, and the
machine moved forward three or four feet by throwing the propelling
gear into motion. After placing the jack screws into their new
position, and tightening them, and blocking the supporting wheels of
the steam shovel, the machine is ready for another series of cuts.
The regular employees for operating a steam shovel are the engineman,
cranesman, fireman and four laborers. The latter are under the
supervision of the cranesman, and their duties are to shovel forward
any lumps or loose material which may roll down and lodge too close to
the front of the steam shovel to be reached by the dipper, to level the
surface of the ground in front of the machine, preparing it for the
next section of track, to lay these sections of track, to attend to the
jack screws and blocking and to act as general utility men.
[Illustration: Fig. 17.--Pole for Breaking Down Edge of Excavation.]
With this crew dry sand and loose gravel can readily be loaded. In
harder or more tenacious materials from two to six extra men are
required, depending upon the kind of material to be excavated, and also
upon good management of the contractor or foreman in charge. Wet sand
and fairly loose gravel requires only two extra men, whose duty is to
break down the overhanging ledges of these materials which cannot be
reached by the dipper, and are liable to fall when the machine has
advanced, burying it or blocking the pit behind it. The implement used
by these men is a pole, Fig. 17, headed by an iron point, resembling a
surveyor's pole. With these poles fairly loose gravel and sand can be
readily broken down, sloped at its natural angle, and fed into the pit
in front of the steam shovel. In harder materials three to four extra
men are usually sufficient, but in very hard or tenacious materials
as many as six must be employed. These men break down overhanging
material in the face of the bank which cannot be reached by the dipper,
bore or drill holes for powder or dynamite when blasting becomes
necessary, cut and remove trees, etc.
[Illustration: Fig. 18.]
On all but very small pieces of railway work there are also employed a
blacksmith and helper, and two to five car repairers. The blacksmith's
work consists mostly of repairs about the cars, mainly bent or broken
aprons, sideboards, chains, etc. The steam shovel occupies much the
smaller part of his time. His accommodation requires a small rough
frame shop about 10 by 16 ft. (an old box car body is frequently used),
with forge and tools. Another rough frame shed of about the same size
is needed for the storage of tools, oils and supplies. The section-men
of the respective sections are occasionally called on for the building
and maintaining (or taking up) of the various side tracks required
during the progress of the work.