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At each watercourse shown in the profile, a brief descrip-
tion is written, giving the character and dimensions of the
structure required at that place. He is given a copy of the
specifications which are to guide him in making a proper
inspection of the work. A suitable offiee is provided him at
or as near the middle of his residency as possible, and fur-
nished with drawing table, drawing materials, field books,
pads, and official stationery. A horse and strong two-seated
buckboard are an important part of his outfit, especially
when in thickly settled country, where the line of road is
readily accessible from public highways.

The first duty of the resident engineer is to check the
alinement and levels on the line of his work, transferring
bench marks from trees or rocks, which are liable to be dis-
turbed, to permanent objects far enough from the center
line to be outside of the slope stakes.

1457. Setting Slope Stakes. His next work is set-
ting slope stakes, commonly called cross-sectioning,
which consists of setting stakes in the ground at the points
which will mark the top of the cut or foot of the slope of the
finished roadway. The following dimensions are suitable
for cross-section stakes: Length, 2 feet; width, 2 inches,
and thickness, 1 inch. They should be planed on one side
to admit of easy marking, and sharpened for driving. In a
country of average smoothness, the level, rod, and tape
are used in locating slope stakes; but in very rough locali-
ties, the Y level is used to carry the continuous line of
levels, while the side elevations, from which the slope stakes
are located, are determined by means of the hand level
and rods.



The process of setting slope stakes is illustrated in Figs.
380 and 381. In Fig. 380, the elevation of the grade is
103.0 feet. The height of in-
strument A is 97.5 feet, and,
hence, the instrument is 5.5
feet below grade. The rod read-
ing at the center line is 6.0 feet,
hence, the surface of the ground
at the center line is below
grade, i. e., there must be a
fill, the amount of which is
made up of two quantities, viz. :
First, the difference between
the elevation of grade and the
height of instrument; and, sec-
ond, the rod reading at the
center line.

The first of these quantities is
5. 5 feet, the second 6.0 feet, and
their sum, 11.5 feet, is the
amount of the fill at center. If
this cross-section is taken at a
full station, there will already
be a stake in place, and the fill
is marked on the back of the
stake F. 11.5. If the section is
taken at an intermediate point,
i. e., a sub-station, say 20+ 50,
the center line is located by rang-
ing in from the stakes at the
regular stations and the stake
is marked 20 -f- 50 on one side
and the fill, F.11.5, on the other
side, and the stake driven with
the numbering facing Station
20. The slope stakes are located by holding the leveling rod
where, in the judgment of the rodman, the foot of the
slope of the completed embankment will be. In Fig. 380,




the rod reading at the right of the center line is 9.5 feet,
which, added to 5.5 feet, the difference between the height
of instrument and
grade, gives a fill of
15 feet. The natural
slope of earth is one
and one-half horizon-
tal to one vertical,
called a slope of 1
to 1. Therefore, in
a fill of 15 feet, the
foot of the slope will
be 1 times 15, which
is 22.5 feet from the
top of the slope, to
which must be added
one-half the width of
the roadway, viz., 8 ^
feet, making 30.5
feet from the center
line. The rod is ac-
cordingly held at 30.5
feet from the center
line. If the rod read-
ing at this distance
is the same, i. e., 9.5
feet, it marks the
foot of the slope, and
a stake marked F.
15.0 is driven in the
place of the rod.
Usually the rod will
not read exactly the
same when held at

the calculated dis- *h Fill 1&2 H

tance, and another calculation will be necessary, two trials
generally proving sufficient. In Fig. 381, the right slope
stake is fixed in the same way. The left slope stake is


located by means of rods and a hand level. First, a point
C is found where the line of sight from the level A cuts
the surface of the ground. A cross-section rod, which is
similar to a transit pole, is held at this point, which is
5.2 feet below grade. At 5.2 feet above C, a rod is held in
a horizontal position, and the point D where it meets the
ground marked by a stake. This point is at grade, i. e.,
where the plane of grade cuts the ground. The stake is
marked by two ciphers 0.0, and its location recorded in the
note book. By means of the rods, the left slope stake at E is
located. As the left slope is in excavation, the left half of
the roadway will be one foot greater in width than the right
half, viz., 9 feet. As the slopes in excavation are but one
horizontal to one vertical, called a slope of 1 to 1, the dis-
tance of the slope stake from the center line is the sum of

one-half the width of the roadway, viz., 9 feet, and the depth
of cutting. In Fig. 381, the cut is 6.8 feet; consequently,
the slope stake is set at 9 -f- 6.8 = 15.8 feet from the center
line. When the cross-section is irregular, intermediate
readings are taken as shown in Fig. 382.

In this section, besides finding the center fill, 6/8 feet at
A, and the fill 14.4 feet at foot of right slope at B, and a fill
of 3.8 feet at C at foot of left slope, intermediate read-
ings are taken at D and E where the slope of the cross-
section changes. These readings are recorded in the note
books, but no stakes are driven at the points of change of



1458. Form of Cross-Section Notes. The levels
are carried continuously from bench mark to bench mark,
the level notes being recorded on the left-hand page of the
note book and the cross-section notes recorded on the right-










W d







Left Line.

Right Line.


S '


(U '















F. 9.0










C.6.8 0.0


15.8 5.0




F.3.8 F.6.8


13.7 8.0

8.0 29.6

hand page. The above form of cross-section notes is simple
and complete, and contains the notes for Figs. 380, 381, and

The cross-section notes are recorded in the form of frac-
tions, the amount of cut or fill being the numerator of
the fraction, and the distance of the slope stake from the
center line, called the side distance, being the denomi-

It will be seen in comparing the notes for Station 20 with
Fig. 380 that the rod reading at the center stake is 6.0 feet,
which gives a center fill of 11.5 feet. The figure shows at
the foot of the right slope a rod reading of 9.5 feet. The in-
strument man instead of determining the elevation of the
ground at this point by subtracting the rod reading from
the height of instrument and then calculating the fill by
subtracting the elevation of the surface of the ground from
the calculated grade for that station, calculates the fill in
this. way. If a rod reading of 6.0 feet gives a fill of 11.5
feet, a rod reading of 9.5 feet must require as inncJi more
filling than 11.5 feet as 9.5 feet is greater than 6.0 feet. The



^ -

















2 o


















difference 9.5 6.0 = 3.5 feet; 11.5 + 3.5 =
15.0 feet, i. e., a rod reading of 9.5 feet
requires a fill of 15.0 feet.

In the notes for Sta. GO, corresponding to
Fig. 382, it will be observed that the inter-
mediate readings taken at D and E are re-
corded in the same order in which they are
taken. The calculations of the side dis-
tances are simple problems in mental arith-
metic, and, with a little practice, they can
be made with great rapidity. A tape
especially adapted to cross-section work is
graduated on both sides, one side giving
the varying fills from 1 foot to 28 feet, and
the other side being graduated to feet and
tenths of a foot. Fig. 383 illustrates the
principle upon which the tapes are made.

As shown in the figure, the eight-foot
mark on the right side of the tape corre-
sponds with the zero mark on the reverse
side. The reason for this is that, whatever
the fill, the slope stake must be placed at
least eight feet from the center line in
order to afford sufficient width for the road-
way. Each division representing tenths of
feet of filling is equivalent to l tenths of
feet of lineal measurement, that is, a fill of 1
foot, as marked on the reverse side of the
tape, corresponds to the division 9.5 feet
on the right side of the tape. In using the
tape, a man stands at the center stake
holding the tape case. The rodman holds
the end of the tape besides carrying the
rod. The man at the center stake lines in
the rodman, that is, he places him as
nearly at right angles to the center line
as he can estimate by the eye. The rodman


first holds the rod at where he judges will be the foot of
the slope. The instrument man calculates the fill and
calls the amount of the fill to the tapeman, who finds on
the reverse side of the tape the numbers corresponding to
the given fill, and holds the tape at that point on the center
stake, causing the rodman to approach or recede from the
center line according as his calculation has differed from the
true one. Again, a rod reading is taken and the amount of
the fill called out, and the corresponding fill being found on
the tape, the rodman is checked again by the level. Two
trials, unless the slopes are very irregular, will generally be

1459. Clearing. All trees, logs, and bushes are
cleared from the right of way. Ordinarily, this work is let
by contract at a fixed price per acre to experienced woods-
men. A skilful axman will fall and trim more trees in one
day than five inexperienced men, and the work will be bet-
ter done. The resident engineer should require the con-
tractor to clear the right of way immediately after his
taking charge of the work, as the work of staking out must
be deferred until after the clearing is completed. As all
timber on the right of way belongs to the railroad company,
the resident engineer should require the contractor to avoid
unnecessary destruction of merchantable timber while clear-
ing the right of way. Timber suitable for cross-ties should
be worked up at once, the ties being piled in safe places and
in such form as will admit of rapid seasoning. Logs large
enough for boards and square timber are piled well out of
reach of the work of construction. Clearing will cost from
120 to $50 per acre.

1460. Grubbing. Grubbing includes the removing
of all trees and stumps lying within the slope stakes in cut-
tings and in embankments where the fill is two feet or less.
Formerly all trees and stumps were grubbed by digging
about the stump and exposing the roots, which were cut off
with an ax. After the large roots were severed, a long


lever was used to complete the work by overturning the
stump. A better method succeeded this very slow ,-jnd
expensive work of grubbing. The trees were left standing
and as soon as the large roots were cut, horsepower was
employed as follows: A strong rope was fastened to the
trunk high above the ground. A strong team (often two
teams) were then hitched to the rope at a safe distance
from the tree. The leverage gained was great, and the tree
could often be overset with half or even less than half the
grubbing that was required by the older process. In mod-
ern practice dynamite is almost exclusively employed. The
trees are first felled and their trunks and branches removed.
A round-pointed bar of steel 2 inches in diameter is driven
at an angle beneath the stump, penetrating far enough to
bring the explosive directly beneath the stump. The bar is
then removed, and the hole loaded with dynamite, precisely
as in blasting rock. A little experience will enable one to
gauge the amount of the charge. The execution of the
powder is thorough, generally blowing the stump, together
with the roots, completely out of the ground and splitting
the stump into several pieces, which greatly facilitates the
work of handling them. In grubbing stumps with dyna-
mite, the gain in first cost over other methods is great, but
the gain in time is greater still.

Grubbing is sometimes paid for by the acre, oftener by
the stump, and in some cases the cost of grubbing is in-
cluded in the price paid for excavation.

As stated in Art. 1433, the clearing of the right of way
will often afford opportunity for slight changes in the line
which will considerably reduce the cost of construction. It
is important that the work of cross-sectioning be completed
at the earliest possible date after construction has com-
menced, as the demands upon the engineer's time multiply
when construction is well under way. Where the line
traverses open and timbered country in about equal propor-
tions, the cross-sectioning on the open stretches can be
pushed while the clearing is being done; in this manner the
work can be kept well in hand.



1461. Classification of Culverts. Culverts are

of three classes, viz., box, tile, and arched. The dimen-
sions of a culvert will depend upon the amount of water to
be discharged. This amount will depend upon the area
and character of the water shed. The engineer can approxi-
mately determine this area either from an inspection of
county maps or from personal examination of the country.
Local records of high water will be of great service to him.
Culverts should always be made large enough to meet the
requirements of the greatest freshets. The following for-
mula is used by some engineers in determining the area of
a culvert opening :

A = C\TM, (102.)

in which A is the area of the opening of the culvert in
square feet, M is the drainage area in acres, and c the vari-
able coefficient depending upon the nature of the country,
1.6 being used for compact hilly ground, 1 for comparatively
level ground, and being raised to 4 for abrupt rocky slopes.
For example, under average conditions, a drainage area
of 200 acres with a coefficient of 1.6 will give the following
cross-section area for a culvert :

A = 1.64/200= 22.62 sq. ft.

In this situation a double-box culvert would be suitable,
with openings three feet in width and four feet in height,
separated by a wall two feet in thickness.

1462. Box Culverts. Foundations will be prepared
as follows: Excavate a pit, including the entire area of the
opening and the side walls, to a depth of 1 foot. Cover
this area with a paving of stones set on edge 1 foot in
depth, with a curb two feet in depth at each face of the
drain, and start the walls on this paving. The paving, after
being laid, should be well rammed, in order to afford a firm
foundation for the superstructure. If the fall of the drain
does not exceed 9 inches, drop the upper end to a level with
the lower end. When the fall is greater than 9 inches,


make a sufficient number
of drops of 9 inches each
to equal the difference in
the elevation of the two
ends of the drain.

At each drop, place a
cross-sill 2 feet in depth.
Box culverts are not made
of greater span than 3 feet.
When a wider opening is
required, a double-box cul-
vert is built with a division
wall 2 feet in thickness.

A general plan for a
single-box culvert is shown
in Fig. 384. The distance
marked 10 ft. is termed
the height of the embank-
ment at center line.

Box culverts are gen-
erally constructed of dry
rubble masonry. The
stones in the abutments
(also called side walls, and
having a height of 3 ft., in
Fig. 384) should be of
good size, faced with beds
roughly dressed and laid
with joints well broken.
Binders reaching through
from face to face of wall
must be used in sufficient
numbers to insure a com-
pact and stable structure.
Covering flags (4 ft. 6 in.
wide and 1 ft. thick, in
Fig. 384) must be of com-
pact stone free from seams


S'O -



and with faces dressed so as to insure a complete cov-
ering. Mortar is used at the discretion of the engineer
in charge. The parapet, 1 ft. thick, is laid on the covering

In soft, marshy soils, a 1-foot paving will not afford a se-
cure foundation, especially if quicksand be present. A pit
2 feet in depth and filled with stone, leaving only sufficient
depth for the 1-foot paving, and well rammed, will, together
with the paving, bear any ordinary box culvert. In wet,
boggy soils, a secure foundation may be obtained by exca-
vating a pit of double the area of the superstructure to the
depth of 2 feet and laying a course of logs of uniform size
over the entire bottom of the pit. A layer of broken stone
is then spread over the logs of sufficient depth to secure a
uniformly level surface. The paving is laid upon this
surface, and the foundation is then in readiness for the

Rule I. To Lay Out a Box Culvert on the Ground.
Take the height of the top of the parapet from the height of
the embankment at the center line. With this difference as
height of embankment, find the side distance as in setting
slope stakes. To these side distances add 18 inches, and if the
embankment is 10 feet in height or over, add I inch on each
end for each foot in height above the parapet.

The covering flags are 1 foot in thickness and the parapet
1 foot in height, making the top of the parapet 2 feet above
the top of the abutment or side walls. The height of the
parapet is, therefore, the height of side walls -|- 2 feet. The
thickness of side walls must never be less than 2 nor more
than 4 feet in thickness.

Rule II. To Find the Length of Wing Walls. Add to
the height of side vvalls the thickness of the covering flags.
One and a half times this sum plus 2 feet will give the dis-
tance from the inside face of the side wall to the end of

The wing walls (marked 8 ft. long, in Fig. 384) must be
parallel to the center line of the road.


EXAMPLE. The roadway is 16 feet in width, the height of the
embankment at the center line is 22 feet, the abutments are 4 feet in
height, the covering flags 1 foot thick, the parapet is 1 foot in height ;
what is (a) the distance from the center line to end of abutment wall,
and (b) the distance from face of abutment wall to end of wing wall ?

SOLUTION. (a) Applying rule I, we have 22 (4 + 2) = 16.
16 X H + 8 + 1 ft. 6 in. + 1 ft. 4 in. = 34 ft. 10 in. Ans.

(b) Applying rule II, we have 4 + 1 = 5. 5 X H 4- 2 = 9 ft. 6 in. Ans.

1463. Tile Culverts. In localities where stone is
scarce and costly, culvert pipe furnishes an economical
and efficient substitute. Culvert pipe is made of clay, which
is subjected to a high degree of heat, when it is known as
vitrified pipe. The manufacture of culvert pipe is carried
on extensively in most of the chief American cities, the
range in sizes being sufficient to meet all requirements.
The pipes vary in length from 24 to 30 inches, and in di-
ameter from 12 to 24 inches. They are fitted with socket
or bell joints similar to those on cast-iron water pipes.

The thickness of the shell is -fa the diameter of the pipe,
and the width of the socket | the diameter. The pipe is
laid on a concrete foundation with sufficient fall to prevent
water from standing in the pipes. A shallow pit is dug to
receive the concrete, the pipes being laid as soon as the con-
crete is in place and brought to a grade. The pipes are
laid with joints of cement mortar, and covered with concrete
to one-half their height; the latter are held in place by side
boards, secured by banking with earth or by stakes driven
in the ground. The concrete affords a secure foundation
and prevents leaking at the joints, which is the chief cause
of failure of pipe culverts with earth foundations.

The parapet walls are of rubble masonry laid in cement
mortar, and carried far enough below the bottom of the
pipe to prevent undermining. In alluvial soils, such as are
traversed by many of our western lines, it is frequently
necessary to carry the parapet walls to a depth of six and
even eight feet to guard against the undermining of the
embankment. The parapet walls need not be built until
after the completion of the road, when the stone may be



hauled by construction trains, thereby saving the great cost
of transporting building stone by teams. A general plan

of pipe culvert is given in Fig. 385. When a single pipe is
not sufficient to pass all the water, two or more pipes are
placed side by side, with concrete well rammed between.


1464. Open Water Culverts. These are generally
of 2 feet span, with walls 2 feet thick, and of not greater
depth than 3 feet. The foundation is of 12-inch paving
placed as in foundations of box culverts. The walls,
directly under the stringers, should be capped with large
well-finished stones, so as to afford good bearings for the
stringers, and properly distribute the loads of passing trains.
Both stringers and cross-ties should be of sawed timber.

1465. Cattle Guards. These are placed on each side
of a public road crossing when the crossing takes place at
grade. Formerly they were built like open culverts, with
spans of from 3 to 5 feet and from 3 to 4 feet in depth. The
abutment walls, upon which the wooden track stringers
were laid, were from 2 to 2 feet in thickness. The rails
were laid directly upon the stringers, thus dispensing with
cross-ties and leaving the space between the rails and abut-
ments entirely open. Although possible for stock to get
into these pits it was almost impossible for them to get out,
and they often proved a cause of instead of a protection
against accident.

The modern cattle guard dispenses with both masonry
and excavation. It consists of two strips of 3-inch plank
laid on cross-ties at a distance apart of 8 feet. Triangular
strips of either wood or iron laid parallel to the rails are
spiked to these pieces of plank, completely covering the
space between the rails excepting space for the wheel flanges.
A space 2 feet in width outside the rails is similarly covered,
the whole closely resembling a gridiron, which is the name
given to this form of cattle guard. It is quickly and cheaply
made and thoroughly efficient.

1466. Open Passage Ways. These are passage
ways for public roads which cross the railroad below grade.
The walls in part serve the purpose of retaining walls, and
should have a thickness at their base of about T 4 T of their
height. The coping of the walls is arranged in the form of
steps, as shown in the general plan of highway culvert; see
Fig. 386. The height A B of the embankment is 15 feet.



The steps C D, etc.,
are so arranged that
the natural slope E F
of the embankment
will just touch the
back of the steps.
The steps are not car-
ried down to the level
of the ground, but
stop at G where the
wall has a height be-
tween 4 and 5 feet.
The section shows the
thickness of the walls,
which are 2 feet
thick on the line of
slope where the steps
chow. The thickness

1 at the base is at all

2 points about T \ of
the height of the
embankment at that
point, giving a thick-
ness of about 6 feet
where the embank-
ment attains its full
height, and finishing
at the top with a
thickness of 2 feet.
The back of the wall
is indicated by the
line H K. The
stringer L consists
of two timbers 8
inches wide by 1(5
inches deep by 17
feet in length, sep-
arated by cast-iron


spools M, and called a packed stringer. The stringers
rest on wooden bed-plates N, N, 12 inches wide by 3 inches
thick, and are notched down 1 inch on the bed-plates.
They are spaced 1 ft. 8 in. from the center line of the track,
and are held in place by a strut O, 3 in. by 12 in. by 3 ft.
4 in. Stringer bolts P of in. round iron pass through both
stringers, one on each side of the strut, and are fastened with

Online LibraryInternational Correspondence SchoolsThe elements of railroad engineering (Volume 2) → online text (page 19 of 35)