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DRAINAGE.

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 are

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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 are made.

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

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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

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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 them.

A section of track ballasted with broken stone is shown in

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Fig. 510. 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.

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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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