1619. Ditching and Ballasting.All railroad managers
and operators are united in their estimate of the importance of
thorough drainage. This can be effected only by a thorough
system of drains and ditches. These should be of such number and
size that they will not only meet the requirements of an ordinary
rainfall, but also of the heaviest freshets.
Ditches are of two kinds, viz., side ditches, those excavated
in cuts on both sides of the road way, and surface ditches, those
excavated above the slope of cuts to prevent the slope from being
washed down. Side ditches are partially made during the grading
of the roadway; surface ditches should always be completed during
construction, as they are of the first importance in affording
protection to the slopes against the floods of surface water which
invariably accompany a heavy freshet. The water which, during
a heavy shower, falls upon the side slopes and track, is about
all that ordinary side ditches can accommodate; and if the protection
of surface ditches is lacking, great quantities of surface water
discharged at different points directly upon the unprotected
slopes, soaking the roadbed, carrying with it quantities of earth
and gravel which choke the side ditches, and, where the quantity
of water is sufficient, producing a washout. In fact, the surface
ditch is indispensable to a newly constructed road, and the question
of its construction should not be open to debate.
As stated above, the side ditches are partially made during
the grading of the roadway, and their completion deferred until
the ballasting and final surfacing of the track. All the material
excavated in completing the ditching should be used in surfacing
the track, and any additional material required should be obtained
by widening the cuts.
Wet, springy cuts are a serious annoyance and expense to any
railroad, especially where the widths of roadways and slopes are
limited by a fixed standard. A cut whose width and slopes are
ample for sand or gravel is totally inadequate for clay. Springs
in the bottom of the cut keep it constantly wet, and a firm track
is impossible. Frost and rain cause the slopes to cave, filling
up the ditches and often covering the ties from sight. Such a
track will be full of sags in summer and badly heaved in winter,
and at no time safe for trains at high speed. There is nothing
to be gained from tinkering with and patching up such a track.
The permanent cure is in widening the cut and reducing the slopes,
so that whatever material caves in will lodge well outside the
ditch line. The ditches should be from 8 to 10 feet from the rails,
and so deep that the ballast will not be soaked by the water flowing
through them. The cost of such work will often be heavy, but it
will end the trouble and prevent the further wasting of money
in useless tinkering.
During the construction of the road, the slopes and
width of roadway should, so far as possible, be
suited to the character of the material in which the excavations
The dotted lines in Fig.
508 show a standard section of a through cut as made during
the grading of the line, and the full lines show the section after
the track has been laid, the cut widened, the ditches made, and
the track ballasted. The
material excavated in this work is used for ballasting the
track. In establishing the grades for a new line, the competent
engineer will make provision for the drainage of the cuts. Sometimes
the grade is continuous throughout the cut, carrying all the water
one way; but where the average grade is level, the drainage is
effected by making the grade to ascend from both ends of the cut,
uniting them by an easy vertical curve at the middle.
Where the cut is short, it is a mistake to break the gradient,
but rather depend for drainage upon well-constructed ditches.
Where the grade of the cut is level, the ditches at the middle
of the cut are made shallow, and the depth gradually increased
towards the ends. The grades of such ditches should be given by
the engineer, and the excavation made to conform to those grades.
It is the continuous grade which gives to a ditch its full efficiency.
Where the grade is a succession of levels and sudden drops, the
level places accumulate mud on account of a sluggish current,
and the steep places wash badly because of a rapid current; and
in a comparatively short time a new ditch must be made.
Particular attention should also be paid to the alinement of
the ditch. Crooks in the ditch impede the flow of the water and
tend to increase the deposit of mud. First determine the line
of the ditch, with a view of avoiding any unnecessary excavation,
and then cut the ditch to a true line.
When gravel or broken stone is used for ballast,
the section of the roadbed is somewhat altered, although its general
dimensions remain the same. As stated in Art. 1603, the
ties should not be bedded when cinders, gravel, or stone
ballast is to be used. A section of roadway ballasted with
either cinders or gravel is shown in Fig. 509. The ballast is filled in between
the ties, flush with their tops, and extends to a depth of 8 inches
below them, sloping from the outer top edge A of the tie to the
edge of the ditch.
On some roads the shoulders at B and C are rounded
off, as shown by the line D E, before the ballast is deposited.
The effect of this is to improve the drainage.
The ditch extends 12 inches in depth below subgrade; i.e.,
the line B C.
The subgrade is the grade line laid down by the engineers
for the grading of the roadway, and marks the bottoms of cuts
and the tops of embankments. The actual grade line marks
the elevation of the top of the rail, and is from 15 to 24 inches
above subgrade. When gravel or broken stone is used as ballast,
the material excavated in ditching the cuts should be loaded on
a gravel train and deposited upon the embankments wherever needed.
The more material deposited on the embankments the better, as
they are bound to cave more or less from the effects of frost
and rain, before grass has grown in sufficient quantities to protect
A section of track ballasted with broken stone is shown in
The ballast extends from 10 inches below the bottom of the ties
to the level of their tops, and is shouldered outwards from the
ends of the ties as shown in the figure. The side ditches are
12 inches in depth, the slope of the ballast and that of the ditch
forming practically a straight line. The slopes of the cuts given
in Fig. 510, as well as those given
in Figs. 508 and 509,
are 1 horizontal to 1 vertical. This is the steepest slope at
which earth will stand. The certain effect of weather is to cause
the slope to cave, flattening it and at the same time filling
up the ditches. In all recent railroad construction, where the
finances of the company will permit, the slopes of both cuts and
embankments are made the, same, viz., 1½ horizontal to
1 vertical. Cuts can be widened much more cheaply before than
after track-laying, but it is often a difficult question to decide
where it is safest to economize.
The proper time to clean ditches is in the fall, commencing
about October 1 and finishing by or before November 1. Occasionally
the slopes of a cut cave in so badly that ditches require frequent
clearing. The only permanent cure is to widen the cut to such
an extent that caving material can not encroach upon the ditches
and track. Some writers on track insist that there should be no
side ditch nearer than 10 feet from the rails, nor slopes less
than 1½ horizontal to 1 vertical. This would require a
roadway at least twenty-four feet in width for a single track,
and involve an outlay which would prohibit the building of nearly
all new lines.
The roadway and track sections given in the preceding pages
are entirely consistent with moderate expense and thorough construction.
When the line is fully equipped, traffic connections established,
and business on a paying basis, there will be ample time for betterments
and a prospect of money with which to pay for them.
The purpose of all ditches and drains is to convey the water
to natural channels and thence out of reach of the track. In Arts.
1461 and 1467, mention was made of the common fault
of making culvert openings too small.
They should be designed to meet the requirements of the severest
storms and freshets. At all low places where the water remains
standing alongside the track, open culverts should be built, allowing
the free passage of the water. Brooks liable to overflow and wash
the track should have their channels deepened or their banks raised.
After every freshet, all water passages should be thoroughly examined
and all obstructions, such as sticks, brushwood, weeds, etc.,
removed. Brush and weeds not only obstruct the passage of water,
but, when dry, are easily ignited by sparks from the engine and
are a continual menace to the safety of the track.
Open passages for water, built of framed timber, are to be
condemned. They are likely to be undermined by a freshet, and
are at best a cause for anxiety. If stone is not available, the
track should be carried on piles. The bents of piles next the
embankment should be sheathed up with plank to prevent the washing
of the embankment.
1620. Side Tracks.The opinion still prevails on
some roads that any kind of work or material will answer for a
side track. This is entirely wrong. The same skill, work, and
materials that go into the main track should be expended upon
all side tracks. The tax upon trainmen and rolling stock is always
greater on side tracks than on the main line, and it is there
that time is either saved or lost. With a good track, shippers
can move a loaded car with a team; whereas, if the track is rough,
they are compelled to wait for a freight train, which must stop
until the car can be shifted. It is admissible to use No. 2 ties
in a side track, except that all joint ties should be strictly
first-class. Where No. 2 ties are used they should be placed closer
together in the track, so as to insure a first-class foundation
for the rails. All side tracks should, as far as possible, have
a switch at both ends. This permits trains to enter the side track
from both directions without passing a switch and backing into
the siding; it also effects a saving of time, labor, and fuel.
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