International Correspondence Schools.

The elements of railroad engineering (Volume 2) online

. (page 13 of 35)
Online LibraryInternational Correspondence SchoolsThe elements of railroad engineering (Volume 2) → online text (page 13 of 35)
Font size
QR-code for this ebook

and when a considerable portion of the ground has been
covered, plat them, and thus avoid the delay incurred by
frequent changes of work. Each engineer decides upon
that form of notes best suited to the character of the work
in hand. The following is a clear and simple form of notes



in which is given the location and elevation of the con-
tours on line B and on the cross-section lines between lines
A and B:

Line B.

Sta. to 1.
+ 3 to contour 75
+ 48 to contour 70
+ 93 to contour 65

Sta. 1 to 2.
56 to contour 60

Sta. 2 to 3.
2 -f- 15 to contour 55
2 -j- 59 to contour 50

Sta. 3 to 4.
3 + 04 to contour 45
3 + 70 to contour 40

Contours Between Lines
A and B.

from A to B 0. .

5 ft. to contour 50
24 ft. to contour 55
43 ft. to contour 60
62 ft. to contour 65
81 ft. to contour 70
97 ft. to contour 75

A 1 to B 1.
12 ft. to contour 45
34 ft. to contour 50
57 ft. to contour 55
79 ft. to contour 60

A 2 to B 2.
1 ft. to contour 35
23 ft. to contour 40
46 ft. to contour 45
68 ft. to contour 50
91 ft. to contour 55

A 3 to B 3.
21 ft. to contour 30
46 ft. to contour 35
71 ft. to contour 40
96 ft. to contour 45


. 785

Line B.

Contours Between Lines
A and B.

Sta. 4 to 5.
4+48 to contour 35

A 4 to B 4.

9 ft. to contour 20

34 ft. to contour 25

59 ft. to contour 30

84 ft. to contour 35

Sta.' 5 to 6.
5 -I- 17 to contour 30
5 -j- 60 to contour 25

A 5 to B 5.
24 ft. to contour 20
55 ft. to contour 25
86 ft. to contour 30

Sta. 6 to 7.
6 -f- 02 to contour 20
6 + 29 to contour 15
6 + 56 to contour 10
6 -j- 83 to contour 5

A 6 to B 6.
22 ft. to contour 5
47 ft. to contour 10
72 ft. to contour 15
97 ft. to contour 20

Sta. 7.

7 + 12 to contour 0,
at edge of lake.

A 7 to B 7.

95 ft. to contour 0,

at edge of lake.

1374. The student having worked up these notes can,
with a little practice, plat them rapidly, using a decimal
scale. A small offset scale is very convenient in locating
contours. The examples given in working up notes will
enable the student to similarly treat the others. He should
be systematic in his calculations and platting, completing
all the calculations on one line before commencing another,
and do likewise in his platting. Otherwise, confusion is
sure to follow.


The elevations of the ground at the intersections of the
division lines are given in the engraving. This is done for
the convenience and assistance of the student. In regular
office work the elevations of these points are taken from the
level book, and the only elevations given in the map are
those of the contours, which are written in gaps left in the
contours for that purpose.

These elevations should be distinctly written, and, unless
the slopes are very steep, bringing the contours very close
together, the elevations should be written successively one
above the other. In drawing the shore line, avoid the
drawing of straight, regular lines. All shore lines, and
especially those of lakes, are very irregular. A heavy line
is first drawn outlining the shore, then a lighter one, at a
small distance from, and parallel to, the first; then another
line, at a greater distance from the second than the second
is from the first ; and so on until the shore line is clearly

The contours themselves are to be drawn free-hand with
an ordinary writing pen.

1375. Second System By Lines of Greatest
Slope. Their direction is that which water would take in
running off them. They are drawn perpendicular to the
contour lines, and are called hatchings. An example of this
system is shown in Fig. 343.

In sketching topography by this system, the topographer
should hold the book directly in front of him so as to corre-
spond with his position on the ground, drawing the lines
towards him. If at the top of a hill, begin by drawing the
lines from the bottom, and vice versa. To guide the hatch-
ings, he should lightly sketch in the contour lines. Hatch-
ings must be drawn truly perpendicular to the contour lines.
Where the contour lines curve sharply, it is often well to
draw in hatchings at considerable intervals as a guide to the
main body of those drawn afterwards. Hatchings in adjoin-
ing rows should not be continuous, but so drawn as to break
joints. They must not overlap, and should be drawn in



slightly wavy lines. In drawing a hill where the slopes are
steep and irregular, it is often well to draw auxiliary

An example of this system is given in Fig. 2 of Plate,
Title: Contours and Slopes, which represents an abrupt
promontory. Its base marks the channel of a river. The
ground on the opposite side of the river is generally level
with occasional undulations. The degree of the slope is
indicated by the spacing of the contours and the correspond-
ing lengths and number of hatchings. The more abrupt
the slope the closer together the contours and hatchings.

The preliminary work necessary for such a "topographical
map is as follows: A traverse or meander line is run, mark-
ing the windings of the stream. Having platted this
meander line, the topographer takes his book containing
the sketch, and from the promontory itself sketches in the
main features of the surface. A hand level is of great ser-
vice in determining relative elevations. From these notes
the final map is made up, the work being done in the office.
Fine topographical drafting should not be attempted in
camp. The facilities of a well-equipped office are necessary
to rapid and satisfactory work. The student is not expected


to reproduce the exact outline of the figure, but it is expected
that his work will show a proper understanding of the sub-
ject. Having drawn the outline of the river, he should
draw in the contours in light pencil lines, spacing them to
conform to the different slopes. It will be evident to the
student that within the space represented by Fig. 2 the sur-
face of the river at C and D will be practically the same.
Hence, if the distance from the summit A to the river at E
is but half the distance from A to F, the slope A E must be
twice as abrupt as the slope A F. Hence, the contours
which mark equal heights will be twice as far apart on the
slope A F as on the slope A E. He should draw all the
contours, outlining the summits at A and B, before com-
mencing the hatchings. The short hatchings on either side
of the river mark its banks. On the promontory side they
are shorter than on the opposite side, as the former has the
more abrupt banks. Fig. 3 of the same plate represents
an irregular and abrupt sea coast. The survey for such an
area would embrace a traverse of the entire shore line of
the island as well as the mainland. This traverse line
should be used as a base line for auxiliary traverse lines, by
means of which the summits A, B, C, D, and E, and any
other important objects could be located. The heights of
these summits could be determined either by triangulation
or by the aneroid barometer. With this information as a
basis, the shore line is located, the contours sketched in, and
the hatchings drawn. As in the case of Fig. 2, the student
is not expected to produce a literal copy, but to show his
proficiency by furnishing a clear and finished drawing.

Hatchings should have their thickness and distance apart
proportional to the steepness of the slope. The lines are
made heavier as the slope is steeper, being fine for gentle
slopes, and for very steep slopes the blank spaces are but
half the breadth of the lines.

1376. Third System By Shades from Vertical
Light. The steeper the slope the less light it receives.
Jn practice, the difference in color is much exaggerated,



Various governments have prepared tables establishing the
ratio of color to different slopes. The shading is applied in
various ways. A rapid method, and a sufficiently accurate
one for many kinds of work, is to sketch in the contours and
then apply the shading in the form of India ink. Each
varying tint is applied with its particular brush, care being
taken not to allow any tint to dry before the succeeding
tint is applied. By this means the tints are blended, giving
a smooth and finished effect to the work. The tints are
made light for gentle slopes and dark for steep slopes, a
slope of 60 being black and one of 30 being midway
between black and white, and so on.

1377. Shades by Contour Lines. This is accom-
plished by interpolating additional contour lines between
the regular contours. Confusion is likely to result from
this method, especially where the slopes are steep, as the
numerous contours are liable to run together or be confused
with roads or boundaries.


1378. Sand, Rock, Etc. Sand is represented by
fine dots made by the point of a pen ; gravel by coarser
dots. Rocks are represented by angular, irregular masses,
as would appear when seen from above and drawn in their
proper places.

1379. Signs for Vegetation. Woods are repre-
sented by scalloped circles, irregularly placed, closer or


FIG. 344. FIG. 345. FIG. 346.

farther apart, according as the forest is dense or open.
Their shadows are drawn on their lower right-hand sides, as
shown in Fig. 34-i. Sometimes trees are drawn in elevation,



as shown in Fig. 345. This method is not admissible ac-
cording to the laws of projection, but it is very effective,
and deciduous trees are more readily distinguished from
evergreen by this method than by that shown in Fig. 344,
where deciduous trees are represented by scalloped circles
and evergreens by stars.

Orchards are represented by trees in regular rows, as
shown in Fig. 346.

Bushes are drawn like trees, but in smaller figures. Fig.
347 represents bushes and trees intermingled.

FIG. 347. FIG. 348. FIG. 349.

Grass land is represented by irregular groups of short
diverging lines, as shown in Fig. 348.

Uncultivated land is shown by inter-
spersing the signs of sand, grass, bushes,
etc. ; cultivated land by parallel rows of
broken lines, as in Fig. 349.

Swamp land is represented by grass,
bushes, and water, as in Fig. 350.

138O. Shore Lines. The sea-shore is represented by
a line following all its windings and indentations. A short

FIG. 351.


distance from the shore line, a parallel line is drawn, and .a
little further removed a second parallel, and so on, as in
Fig. 351.

An abrupt and rocky shore is shown in Fig. 352. The
irregular dotted surfaces surrounded by shore lines represent

sand bars. The dotted outlines beyond the shore lines
represent either shoals or sunken rocks.

Rivers have their shore lines treated in the same manner
as the sea-shore,, as shown in Fig. 353.

Large brooks are represented by two parallel lines; small
brooks by a single line.


1381. Grounds and Gardens. Grounds and gar-
dens are represented in plan as follows: The grounds, by
boundaries of property and street lines; the house and other
buildings, by their ground plan, and drives, walks, lawn,
shrubbery, and trees, by either outlines or conventional
signs. The gardens by rectangular beds and other forms
of arrangement.


1382. Fig. 1 of this plate illustrates the use of conven-
tional signs in practical landscape gardening, affording the
student some knowledge of how a given area may be dis-
posed so as to combine artistic arrangement with practical
utility. It contains a plat of a house, grounds, and gardens
drawn to a scale of 50 feet to the inch. All necessary di-
mensions are given for an accurate reproduction of the
work. The student should first carefully study the outlines,
and accurately determine their dimensions, after which
the details will be a simple matter.

In drawing Fig. 1, first lay out the boundaries of the plat
of ground, 375 ft. front by 515 ft. deep.

The width of the street fronting the lot is 60 ft. From
the front corners of the lot A and 'A', measured B and A' B',
each 17 ft., locating the center line of the carriage drive.
From B and B' measure 100 ft., locating the centers C
and C'. From these centers with equal radii C B and C' B'
describe equal arcs B D and B' D' containing 30. Pro-
duce the radii C D and C' D' until they intersect at E. If
the work has been correctly done, E will be equidistant
from the corners A and A'. Through E draw a line E E'
Sit right angles to the line A A'. This line will divide the
lot into two equal parts and form the main base line for the
location of points in the plat. With the radius E D 181 ft.
in length describe the arc D D', completing the center line
of the front carriage drive. The drive is 15 ft. in width.
The inner boundary is described by simply reducing the
length of the radius 7 ft., and the outer boundary by in-
creasing the length an equal amount. We next measure


from the street corner A on the left boundary the distance
A F= 300 ft., and at F draw F F' perpendicular to A F.
At some point G of the main base line E E ', draw G G'
perpendicular to E E' and 95 ft. in length. At G ', the ex-
tremity of this perpendicular, draw a line H H' perpen-
dicular to G G' intersecting F F' at /, which point is the
center of an elliptical curve in the carriage drive. The
major axis K K' of this ellipse is 85 ft., and the minor axis
L L' is 66 ft. in length. This ellipse the student will draw
according to the method described in the section on Me-
chanical Drawing. Having drawn the ellipse, the student
will readily draw the border lines of the drive by increas-
ing or reducing the lengths of the various radii.

Draw both outer and inner boundaries of the ellipse in
pencil so as to form closed figures. From some point M
of the street line draw MM' 213 ft. in length and parallel
to E E'. Through M 1 draw M' M" , perpendicular to E E'.
From E E' and M' M" locate the house from dimensions
given. From some point N of E E ', draw N N' 110 ft. in
length and perpendicular to E E' . At N' draw in both
directions an indefinite line perpendicular to N N'. At some
point O of the line E E' erect a perpendicular O O' 35 ft. in
length, and through O' draw an indefinite line parallel to
E E'. From a point O' of this line with a radius of 100 ft.
describe an indefinite arc P P', being careful that the
extremity P shall be in a tangent to the center line at the
carriage driveway. Then, from some point Q, found by
trial, with a radius of 50 ft. , describe an arc P' N' which shall
be tangent to the straight line through TV' and the arc P P'.
In a similar manner find centers at the points./?, S, T, and [7,
from which with the given radii describe arcs forming the
center line of the carriage driveway. Having located the
center line complete, the boundaries are put in as previously
directed, being careful to unite the various curves with
smooth, even lines. The arc described from the center U
must be tangent to the ellipse and to the center line V V ',
which is 15^ ft. distant from the boundary of the lot. The
stable lot is 75 ft. square. The buildings may be readily


located from figures given in the drawing. The kitchen
garden extends from the rear boundary of the lot 150 ft.
towards the street, and from the right-hand boundary to the
driveway and stable yard. It is divided into rectangular
plots, the various sizes being suited to the character of
the vegetables grown. All dimensions necessary for a
reproduction of the drawing are fully given.

1383. Fig. 2 shows a portion of a town, together with
its connections with railroad and canal. The student will
make the drawing to a scale of 200 feet to the inch.

Before commencing this plate the student will note that
the magnetic meridian is parallel to the right and left borders
of the plate. At 250 ft. from the S W corner of the plat
we locate a plug, which is the starting point for the traverse
of the river. Call this plug Sta. 1. Thence, run N 22 30' E
734 ft. to Sta. 2; thence, N 60 30' E 57G ft. to Sta. 3, the
center of Main street ; thence, N 68 1*5' E 430 ft. to Sta. 4.
At. 100 ft. from the starting point the river is 30 ft. to
right; at Sta. 2 it is 70 ft. R. ; at Sta. 3, 40 ft. R. ; at Sta. 4.
44 ft. R. The river has an average width of 400 ft. The
student will draw in the shore line from the offsets given
above, giving it the same contour as shown in the plate.
The opposite shore the student will locate by offsets, avera-
ging 400 feet each. Again starting at Sta. 3 of the river
traverse, a line is run N 16 W along the center of Main
street, producing the line backwards from Sta. 3 across the
river and beyond to the boundary of the plat. The several
lines of survey will be used as base lines for the location of
streets, railroad tracks, canal, and all objects included in the
map. The starting point of each line of survey is numbered
zero, and all lineal base-line measurements are referred to
the starting or zero points. Distances measured on the base
line are expressed in stations of 100 ft. each, and offsets are
given in full. Calling Sta. 3 of the river traverse 0, we
measure northward to Sta. +90, the north end of the river
and canal bridge. The wing walls of the abutments diverge
at an angle of 30. At Sta. 4 + 93 is the center of the track


of the P. & N. R. R., the bearing of which is N 73
30' E.

At Sta. 5 + 68 is the center of Putnam street, the bearing
of which is N 73 30' E. At Station 11 -f G8 is the center
of Randolph street, the bearing of which is N 73 30' E.
Produce the center lines of both Putnam and Randolph
streets until they intersect the boundaries of the plat. Main
street is GO feet in width, and Putnam and Randolph streets
are each 50 feet in width. Draw parallels to the center lines
of these streets, locating the proper boundaries as shown in
the plat. From the intersection of the center line of Mam
with that of Putnam street, measure eastward on the center
line of Putnam street 450 ft. to the center of Tyler street,
the bearing of which is N 3 45' W. Produce the center line
of Tyler street northward until it intersects the north bound-
ary of the plat. On the N E corner of Main and Randolph
streets is a hotel fronting 110 ft. on Main and 100 feet on
Randolph streets. The hotel has a depth of GO feet from
each frontage. On the S W corner of Main and Randolph
streets is the postoffice, fronting 60 ft. on Main street and
40 ft. on Randolph street. Returning to the starting point,
viz., Sta. 3 of the river traverse, and running southward on
the center line of Main street, at Sta. + 34 is the center
of the shore pier, 10 ft. by 40 ft. ; at Sta. 2 + 34 is the center
of the channel pier, 12 ft. by 40 feet, and at Sta. 4 + 34 is
the south end of the bridge. The bridge is 30 feet wide.
The wing walls of the south abutment also diverge at an
angle of 30. The south approach is 40 ft. in width and 200
ft. in length. Beyond the approach the street has the full
width of 60 feet.

At 100 ft. east of the S W corner of the plat is the cen-
ter line of the S. & B. R. R., which has a double track, the
track centers being spaced 13 ft. apart. The bearing of this 1
tangent is N 15 15' E, and the given point is numbered
Sta. 0. At Sta. 5 is the center of the towing path of the
C. & O. canal, the bearing of which is N 54 30' E. At
Sta. 9 + 44.1 is the P. C. of a 6 curve L. for 30. The
student will produce the center line to Sta. 12, which is the


point of intersection for the curve, laying off the tangent
distance of 255.9 ft. Draw the center line of each track,
spacing them 6.5 ft. from the main center line. Having
located the center of the 6 curve, the parallel curves are
struck with a compass, increasing the radius 6.5 ft. for the
outer curve and diminishing it the same amount for the
inner curve. North of Putnam St. the right of way of the
S. & B. R. R. is 100 ft., 50 ft. each side of the main center
line. Parallel to this center line on each side of the railroad
is a street 40 ft. in width. Produce the center line of the
east track of the S. & B. R. R. until it intersects the center
line at the P. & N. R. R. The intersection angle is 57 30'.
Unite these tangents by a 10 curve. At Sta. 6 + 63 of the
S. & B. R. R. west track, is the P. C. of a 16 curve L. for
27, which we call track A.

At 40 ft. from the P. T. of this curve is the center of a
turntable, the diameter of which is 60 ft. From the cir-
cumference of the turntable to the inner wall of the round-
house is 60 ft. The right-hand end wall of the roundhouse
faces on a radial line from the center of the turntable, which
line makes an angle of 30 30' with the tangent of the turn-
out curve. The left-hand end wall is similarly situated,
making an angle of 91 30' with the tangent of the turnout
curve. The depth of the stalls is 70 ft. The tracks at the
inside wall line are spaced 15-ft. centers. From the center
of the outside track to outside of end walls is 10 ft. At
Sta. 8 + 92 of the west track is the P. C. of a 10 turnout
curve, to left, for 30 10'. This we call track B. The P. T.
is on the line of the south end wall of a car shop. The side
walls of the car shop are parallel to the tangent of the curve.
The east wall is 15 ft. from the center line of the tangent
and the west wall 50 ft., giving a total width of 65 ft. The
length of the car shop is 200 ft. At the northwest corner of
the car shop is an engine and boiler house 40 ft. square.

On the north side of Putnam street is a foundry, fronting
120 ft. on Putnam street and 175 ft. on Foundry street, the
building having a depth of 50 ft. from both frontages. The
east side of the building is parallel to the tangent of the


turnout curve leading to the car shop, and 10 ft. from it.
At Sta. 11 + 55, as measured on the produced tangent of
the S. & B. R. R. is the south end of the platform of the
R. R. station. At Sta. 12 is the south end of the station
proper. The station is 07 ft. long, as measured on this tan-
gent. The outer edge of the platform is 8 ft. from the cen-
ter line of the adjacent tracks. The platform is 10 ft. wide
and extends on all sides of the station, the curved walls of
which are parallel to the railroad tracks.

At Sta. 8 of 'the S. & B. R. R. is the P. C. of a 10' turn-
out curve R., which leads from the east track, containing
39 50', and called track C. A tannery, 300 ft. in length by
90 ft. in width, extends from the P. T. of this curve, parallel
to and 20 ft. to the right of the center line of the tangent.
A bark shed of the full width of the tannery forms a con-
tinuation of the tannery and extends to Main street. A
platform 10 ft. in width extends the entire length of the
tannery, between it and the tracks. At the southwest cor-
ner of the tannery is an engine and Jpoiler house 50 by 80 ft.
At GO ft. from the P. C. of track C and tangent to that
curve, track D commences.

At 5-4 ft. from the commencement of track D is the P. C.
of a 23 curve R. for 28 38', and called track , which ter-
minates in a tangent parallel to the tangent of track 7 L and
spaced 12 ft. from it. At 3G4 ft. from the P. T. of track
E is the west end of a coal chute. The south side of the
chute is 8 ft. from the center of the track; the north side
is 22 ft. from the center of the track, which gives the build-
ing a total width of 30 ft. It extends in length to Main
street. At 257 ft. from the commencement of track D is
the P. C. of a 1G curve R. for 31, and called track F. At
8 ft. to the right and parallel to the tangent of this curve
is a freight depot, extending from the P. T. of the curve and
200 ft. long by 35 ft. wide. On the south side the freight
station is a platform 10 ft. wide, extending its entire length.
At 312 ft. from the commencement of track D is the P. C. of
a 23 curve R. for 31, the tangent of which is parallel to
track F, their center lines being spaced 12 ft.


Between Sta. 5 + 78 of the S. & B. R. R. west track, and
Sta. 7 + 51, east track, is a cross-over track, which we call
track G. This consists of two turnout curves, one com-
mencing at each of the given stations and intersecting on
the main center line. The curve commencing at Sta. 5 + 78
is a 9 30' curve R. ; the curve commencing at Sta. 7 + 51 is
also a 9 30' curve R., but described in the opposite direc-
tion. If carefully drawn, these curves will intersect on the
main center line. Between Sta. 14 + 44.1, east track, and

Online LibraryInternational Correspondence SchoolsThe elements of railroad engineering (Volume 2) → online text (page 13 of 35)