chains in length, and 53 feet in its greatest depth. | sponding to that shown in Fig. 1860 The lower The strata intersected are the upper soil ss, Fig. 1860, part, extending upward to a height ranging with the of a light sandy kind, with clay from 2 to 10 feet thick, undersetting of masonry beneath the rock, which is and lying mainly in blue, yellow, and brown marl, and continued throughout the excavation, is formed to a red clay, of an average thickness of 20 feet. Under curved batter of 106 feet radius. The average vertithese is the limestone rock RR, of various degrees of cal height of this undersetting above the level of rails hardness, and in beds of 1 to 4 feet in thickness, but is 20 feet. The rock above is sloped at to 1, a without any mixture of shale, and having springs of benching of 9 feet wide being left on its upper surface, water in the lower beds. At the east end of the and the superior soil trimmed to a slope of 2 to 1. section the limestone rock crops out, and the superior The method of draining is also shown in the figures, stratum of marl disappears. Beneath the limestone together with the inverts I and buttresses B for supis the blue shale: it appears to be dished on the porting the undersetting. Fig. 1860 is a cross section, upper surface, being about 6 feet thick at the east one half being taken through the wall, the other end, extending about 20 chains, then ranging beneath through one of the buttresses. Fig. 1861 is a secthe railway level, rising again at the end of 75 chains, tional plan of half of the excavation, showing the and acquiring a thickness of nearly uniform increase recess wall, 2 feet 6 inches thick at top, battered in of 30 feet at the western extremity of the section, front to a slope of 2 inches to 1 foot. The centre where it outcrops beneath the limestone. drain D, 1 foot 9 inches wide; and the cross drains d d, are shown in section. PP shows the pitching and II the invert arches. Midway, between each 2 contiguous buttresses, a vertical drain, or gullet, d, is formed on the face of the wall, receiving the drainage water by oblique drains, shown in dotted lines, from the puddling p at the back of the wall. At the west end the excavation is formed to a slope of 2 feet base to 1 foot height throughout its whole The quantity of material removed from some cuttings is enormous. Thus, to cite a few examples:-the Oakenshaw cutting on the North Midland railway is in rock-shale and bind: the greatest depth is 50 feet, and its contents 600,000 cubic yards, most of which was led to form the Oakenshaw embankment. The Normanton cutting has a maximum depth of 55 feet: it contained 500,000 cubic yards, chiefly rock, and blue bind: most of this was led to form the Altofts embankment, and 70,000 cubic yards were thrown out " to depth for a distance of 22 chains, the inferior stratum | spoil." The progress of the works was so rapid in 1839, of shale being faced with rough stones. Through that 450,000 cubic yards of excavation were effected per month. The number of men employed was 8,600, and there were 18 fixed engines working chiefly at tunnels. Much trouble and expense are occasioned by the slipping of the slopes. In a cutting which was to be formed in the side of a hill in the north of England, it was calculated that about 50,000 cubic yards of earth would have to be removed. It happened, however, that the soft earth was upheld by a seam of shale, which was no sooner cut through than a mass of earth slipped down into the line of the railway, to such an extent as to require the removal of about 500,000 cubic yards. In excavating through hills of considerable height, it is important to get a fair face to the work, or one at right angles to the direction of the cutting, and from this face to start a system of gulleting or notching. In this way labour is economised. As the work proceeds into the hill, and the width is increased in order to provide for the slopes, it is desirable to run a gullet along the centre of the cutting, in order to bring a larger number of waggons into use at one if the banks were carried forward with one batteryhead across the whole width of the work. The kind of waggon employed in embanking de pends to some extent upon the material. Those called end-waggons, Fig. 1862, discharge their kn from the back or end; side-waggons are emptied at the side. The waggons move on a hinge, and by the motion of a lever are tilted or tipped over as soon as time. In this gullet temporary rails are laid down, | any alteration in form and position is less likely th and the train of waggons is sent forward to receive the produce of the barrowing on either side. As the height of the hill increases, a second layer is commenced, and a side track is laid, inclining down on each side of the lower level. On these lines the full waggons descend on one side, and the empty ones are drawn up by horses on the other. Horses are also used for moving the full waggons to the head of the incline, down which they descend by their own weight. One of the great inconveniences of excavating is the accumulation of water in the lower parts of the cutting: this is prevented by keeping the bed of the cutting inclined upwards so as to conduct the water away. When the lead is in both directions from the centre of the intended excavation, and it is required to send the materials got out to each end of the hill, the excavation is begun at both ends and terminates in the middle: in such case there is a rise from each end to the centre for the purposes of drainage. In many cases the plough is used preparatory to excavation: it is very effectual in loosening the surface. In America a scoop has been found of advantage. In so extensive a work as a railway over an undulating surface, it is of great importance that the amount of excavation and embankment should be balanced as nearly as possible, to prevent the necessity of depositing the earth from cuttings in spoil-banks, or of having to purchase land for furnishing material for embankments. If a cutting were found to yield a surplus of material, a short tunnel would be preferable to a cutting; but if material for embanking be wanted, then the cutting would be preferable to the tunnel. It is generally contrived, for the sake of economy, that a cutting and an embankment shall be carried on simultaneously; but the cost of the embankment will be considerably influenced by the length of the lead, or the distance to be traversed by the earth-waggons between the points of filling and emptying. The usual and quickest mode of forming an embankment is by running it out to the full depth required at once. The front end of the embankment where the formation is proceeding, and over which the material is tipped, is called the battery-head. Temporary lines are laid down with edge-rails and wooden sleepers, in a double line, with crossings near the battery-head for the waggons to cross over as soon as they have tipped over their contents, when they return to be filled by one line, while the full waggons are proceeding along the other. The method of forming embankments for common roads has already been noticed. The subsidence of newly-made embankments, in some cases leads to considerable expense and even danger. There are various methods of embanking, that method being the best which combines stability with economy. With this view many engineers prefer to run forward the two sides of the embankment to the full width, leaving a central valley to be filled in at some little distance in the rear. The effect of this arrangement is, that the two sides act as separate embankments, and resist the thrust of the central part afterwards put in; and Fig. 1862. the wheels strike against a fixed stop or bar at the battery-head. Fig. 1863 shows a form of waggona which is more readily emptied than when the body Fig. 1863. turns on a hinge. The body is supported on 2 rollers, and when the waggon suddenly stops at the tip, the momentum of the load carries the body forward until its centre of gravity gets beyond the support, and the body is instantly tilted. The body is prevented from overrunning by a pair of curved metal stops, which are checked against the front rollers. All the waggons are provided with simple brakes, consisting of a block of hard wood, shaped so as to fit a portion of the periphery of the 2 wheels, and capable of being turned on a centre by means of a long handle of iron which is carried to the front or hind part of the waggon, so as to be acted on by the hand or foot of the brakesman. The handle moves within an iron slot, and may be secured in any position by a pin passed through it. The earth-waggon is nearly square in form, having a slight taper or increase of width towards that end of the waggon which is turned downwards in the act of tipping. Each waggon contains about 24 cubic yards: the wheels are 3 feet in diameter; the wood-work is of English elm. Under the framing a sole should | but when it is considered that, from the nature of the project beyond the body to leave room for the driver ground, an iron rod would sink by its own weight, to escape in case the sole ends or buffers should be it must be confessed that such an undertaking as carforced violently together. Waggons are also con-rying a railway along, under, and over such a material, structed of iron. One of the most celebrated embankments is that over Chatmoss, on the Liverpool and Manchester line, formed in the infancy of railroads, and in opposition to the opinions of eminent engineers as to its practicability some declaring before a parliamentary committee that it would be utterly impossible to carry a line over this bog without first cutting down 33 or 34 feet to the solid bottom; others declaring that a cost of 200,000l. would not suffice for the work: and yet, although the moss contained nearly double its bulk of water, a safe embankment was formed over its surface at a cost below the average of other parts of the line. The tribute of respect paid to the engineer of this great work by a celebrated French writer,' will be a sufficient excuse for quoting the passage : would never have been contemplated by an ordinary mind. In a smaller moss, which had also to be crossed, and which was about 20 feet deep, although an embankment of only 4 feet high was required, the clay and gravel tipped amounted to as much as would form one 24 feet high on ordinary ground." In districts where stone is plentiful, the method of forming embankments and cuttings, shown in Figs. 1864, 1865, may be economically adopted. The embankment, or lower part of the cutting, is faced with rubble-work with a batter sufficient for its stability. On the Leeds and Selby line this facing to the embankments has a curved batter, the chord line of which forms an angle of 67° 30′ with the horizon. These embankments must be provided with strong parapets P, Fig. 1864. D D Fig. 1865. "The depth of the moss varied from 10 to 34 feet, and its general character was such that cattle could not walk on it: the subsoil was principally composed of clay and sand, and the railway had to be carried over it upon a level, and required cutting and embankment for upwards of 4 miles. Where the mode of doing this required an embankment, the expense of which, in the ordinary method, would have been enormous, as it must have been bottomed upon the subsoil of the moss, Mr. Stephenson contrived to use the moss itself in the following manner :-Drains about 5 yards apart were cut, and when the moss between them was perfectly dry, it was used to form the embankment, and so well did it succeed, that only about to prevent the train from falling over in case it should 4 times the quantity was required that would have run off the line rr. When this occurs on the edge of an been necessary on hard ground. Where the road was embankment formed of soil, and sloped at 2 to 1, the on a level, drains were cut on each side of the in- train would probably be arrested by sinking in the tended line, by which, intersected with cross ones yielding material, which would evidently not be the occasionally, the upper part of the moss became dry case in embankments faced in this manner, with steep and tolerably firm: on this hurdles were placed, either sides. In this method there is much economy in the in double or single layers, as the case required, 4 feet amount of earth-work to be embanked, and in the broad and 9 feet long, covered with heath; on these width of land required; it also gives great facility of was laid the ballast, and the method was fully success-drainage and ensures stability. An open longitudinal ful. Longitudinal bearings, as well as cross sleepers, were used to support the rails where necessary, and the whole was thoroughly drained. In the cutting, the whole had to be accomplished by drainage entirely. Longitudinal drains, about 2 feet deep, were cut on each side of the intended line of railway, and when by this means the upper surface of the moss had become dry, about 12 or 15 inches in depth were then taken out, as in an ordinary case of excavation; the drains were then sunk deeper, and another portion taken out when dry, as before; and thus, by alternately draining and excavating, the depth required for the railway was attained, which in some instances was 9 feet, the embankments being as high as 12 feet. The only advantage in favour of these operations was, that the surface of the mosз was higher than the surrounding country, which partially assisted the drainage; drain or channel d being formed behind the parapets, and made to communicate with vertical or oblique channels formed on the face of the stone-work, conducts all the water to the toe of the embankment, whence it is readily withdrawn by side ditches. The slope of the earth-work above is also efficiently drained by a longitudinal channel D D behind the top of the facing, connected either with channels on the face, or perpendicular drains behind, with cross drains leading into the centre one C D, as shown in Fig. 1865. The effectual drainage of the artificial works connected with a railway is of the utmost importance. The failure of many earth-works is to be traced to that secret and insidious enemy, water. Whenever about the works it is even suspected to exist, it should be traced to its source and diverted from slopes and adjoining surfaces. Beneath embankments every stream should be intersected, and every field, ditch, or other natural or artificial water-way, should Big Asr artice best, moms 26lan tas respecting the theBrands á vOOM LAGS di uniga, i la not necesBarĮ V, E, kde the shatrata di nový turs doug many of them present pect kuma, with a marina zerer king, the grien tom ne visent to the other, and sup1 Agava, ra palea, or planks when the rall vay peaves over asth a bridge, gren are weg, & cf wilch sustain the rasa, and the other 2 sue parapeta, a light fooring of wa pula viq osastructed between the girders. Ia arrangement give great strength, and superworn the meauty for balast, thus reducing the Gega O NAKLew of the bridge to a milim.m In order to preserve the straightness of the railway, akem na Agga are required at points where the railway interweta any existing communications at an oblique ange. Hence, in creting such a road by a skew broge, the comm. dications over and under the bridge form unequal angles with each other. Many beautiful examples of brick and masonry-work are afforded by thew ingenious structures. Is was ascertained a 1997 t for every sic I've permanent way.-Wen Le top surfaces of the The Britannia tubular bridge is fully described under Bridor. Another structure, equally remarkable The ballasting, which should be from 18 to 24 in its way, in the high-level bridge at Newcastle-upon- inches in thickness, consists of very various materials, Tyne, which forms the junction between the York and such as can be most readily and cheaply procured. Newcastle, and the Newcastle and Berwick railways. Those in common use are burnt clay, burnt marl, This bridge was projected by Mr. Hudson, and de- rock marl, gravel, broken sandstone and lias, oolitesigned by Mr. Robert Stephenson: it extends from stone, &c. Loam does not afford a good ballast, but the castle-garth on the north, to the high ground on a mixture of chalk and flints is good, or a mixture of the south side of the river. There are two roadways, sand and broken stone; gravel and broken limestone one level with the castle-garth, for carriages and foot- form a good binding material, but gravel alone, or passengers, and the other at an elevation of 22 feet gravel and sand, or broken stone alone, does not bind above it. The carriage-road is 1,350 feet in length on well. Sand is very objectionable as ballast; it is a straight line. The bridge is 112 feet from high-raised up by the wind or by the draught occasioned water line to the top of the parapet, and the roadway by the velocity of the train, settles among the bearis 80 feet above the water. Six arches, each of 125 ings, and gets between rubbing parts, cutting and feet span, form the bridge,-the piers upon which they wearing them away in a very remarkable manner. rest being of masonry, and the arches, pillars, braces, Cinders, or small coal, are used as ballast, where and transverse girders, of iron. The bridge-piers are these materials are abundant. Where stone is plen nearly 50 feet by 16 feet in thickness, and in extreme tiful, the whole line is sometimes pitched transversely height are 131 feet from the foundation, having an with thin stones, and on this a bed of broken stone opening in the centre through each. They are erected is spread for ballast, after Telford's plan for common on piles, which pierce the bed of the river, about roads. 50 feet on the north side, and 20 on the south. The land-arches of the bridge diminish in altitude from the foundation upwards, corresponding with the steep bank of the river. The roadway for vehicles beneath the railroad is suspended from the (1) "Our Iron Roads, their History, Construction, and Social Influences." By Frederick S. Williams. 8vo. London. 1852. (2) Probably so called in contradistinction to the temporary way, which is laid down in the first instance to facilitate the construetion of the line. The foundation of the permanent way is now | log is from 7 to 9 feet in length. On the South formed of timber. Formerly, as noticed in our histo- Eastern Railway the sleepers are of Baltic fir, cut rical sketch, blocks of stone were laid down, either from square baulks, each being divided diagonally into square with the railway or diagonally, for the recep- 4 triangular sleepers. They are laid with the right tion of the chairs for holding the rails; but the weight angle downwards, and thus present as large a surof the passing train tended to thrust them asunder, face for the chairs as the half baulks, and offer great and thus to disturb the gage of the line. The weight facility for packing the ballast. See Figs. 1874, 1875. of the blocks was also found to disturb the stability The distance between the cross sleepers should be of bridges and other constructed works. Timber, some aliquot part of the length of the rail: it should therefore, again came into general use, and is now not exceed 3 feet 9 inches, unless a very heavy section preferred. It is first prepared by kyanizing, or im- of rail be used. With a 15-feet rail the distance of 3 pregnating it with certain saline substances, a process feet is often allowed, and is said to give greater steadiwhich is said to confer on soft wood the durability of ness and equality of motion; and in some cases 2 feet oak. Timber is used for the cross sleepers of suffi- 6 inches has been adopted for a light rail and a small cient width to support a pair of chairs, as in Figs. 1866, chair. Taking all the variations at present adopted, 1868, or it is used in continuous longitudinal lengths, rails are laid on supports at 3 feet; 3 feet 6 inches; 3 feet 9 inches; 4 feet; and 4 feet 6 inches asunder. Various sections of rails are shown in Fig. 1870. The double T rail, No. 3, is a very common form on many Fig. 1871. recess, and the space left between the straight cheek of the chair and the other side of the web of the rail, is occupied by the wooden key or wedge driven in until the rail is firm in the chair. After dry weather the keys shrink and become loose, and require a few blows with a mallet to tighten them. This inconvenience is remedied by compressing the wood before it is inserted, for which purpose the oak keys are steamed, shaped, and then forced through an iron |