Chapter 3

The leading dimensions of the eight wire rope tugs now worked by the company are as follows:

Tugs No. I. to Tugs No. V. to IV. VIII. Meters. ft. in. Meters. ft. in. Length between perpendiculars 39 = 126 0 42 = 137 10 Length over all 42.75 = 140 3 45.75 = 150 1 Extreme breadth 7.2 = 28 8 7.5 = 24 5 Height of sides 2.38 = 7 11 2.38 = 7 11 Depth of keel 0.12 = 0 5 0.15 = 0 6

All the boats are fitted with twin screws, 1.2 meters (3 feet 11¼ inches) in diameter, these being used on the downstream journey, and also for assisting in steering while passing awkward places during the journey up stream. They are also provided with water ballast tanks, and under ordinary circumstances they have a draught of 1.3 to 1.4 meters (4 feet 3 inches to 4 feet 7 inches), this draught being necessary to give proper immersion to the screws. When the water in the Rhine is very low, however, the water ballast is pumped out and the tugs are then run with a draught of 1 meter (3 feet 3 3/8 inches), it being thus possible to keep them at work when all other towing steamers on the Rhine are stopped. This happened in the spring of 1882.

Referring to our engraving, it will be seen that the wire rope rising from the bed of the river passes first over a large guide pulley, the axis of which is carried by a substantial wrought iron swinging bracket, this bracket being so pivoted that while the pulley is free to swing into the line on which the rope is approached by the vessel, yet the rope on leaving the pulley is delivered in a line which is tangential to a second guide pulley placed further aft and at a lower level. This last named guide pulley does not swing, and from it the rope is delivered to the clip drum, over which it passes. From the clip drum the rope passes under a third guide pulley; this pulley swings on a bracket having a vertical axis. This third pulley projects down below the keel of the tug boat, so that the rope on leaving it can pass under the vessel without fouling. Suitable recesses are formed in the side of the tug boat to accommodate the swinging pulleys, while the bow of the boat is sloped downward nearly to the water line, as shown, so as to allow of the rising part of the rope swinging over it if necessary.

The hauling gear with which the tug is fitted consists of a pair of condensing engines with cylinders 14.17 inches in diameter and 23.62 inches stroke, the crankshaft carrying a pinion which gears into a spur wheel on an intermediate shaft, this shaft again carrying a pinion which gears into a large spur wheel fixed on the shaft which carries the clip drum. In the arrangement of hauling gear above described the ratio of the gear is 1:8.44, in the case of tugs Nos. I. to IV.; while in tugs Nos. V. to VIII. the proportion has been made 1:11.82. In tugs I. to IV. the diameter of the clip drum is 2.743 meters (9 feet), while in the remaining tugs it is 3.056 meters (10 feet).

From some interesting data which have been placed at our disposal by Mr. Thomas Schwarz, the manager of the Central Actien-Gesellschaft fur Tauerei und Schleppschifffahrt, we learn that in the tugs Nos. I. to IV. the hauling machine develops on an average 150 indicated horse, while in the tugs No. V. to VIII. the power developed averages 180 indicated horse power. The tugs forming the first named group haul on an average 2,200 tons of cargo, contained in four wooden barges, at a speed of 4½ kilometers (2.8 miles) per hour, against a stream running at the rate of 6½ kilometers (4.05 miles) per hour, while the tugs Nos. V. to VIII. will take a load of 2,600 tons of cargo in the same number of wooden barges at the same speed and against the same current. In iron barges, about one and a half times the quantity of useful load can be drawn by a slightly less expenditure of power.

The average consumption of coal per hour is, for tugs Nos. I. to IV., 5 cwt, and for tugs Nos. V. to VIII., 6 cwt.; and of this fuel a small fraction (about one-sixth) is consumed by the occasional working of the screw propellers at sharp bends. The fuel consumption of the wire rope tugs contrasts most favorably with that of the paddle and screw tugs employed on the Rhine, the best paddle tugs (with compound engines, patent wheels, etc.) burning three and a half times as much; the older paddle tugs (with low pressure non-compound engines), four and a half times as much; and the latest screw tugs, two and a half times as much coal as the wire rope tugs when doing the same work under the same circumstances. The screw tugs just mentioned have a draught of 2½ meters (8 feet 2½ inches), and are fitted with engines of 560 indicated horse power.

During the years 1879, 1880, and 1881, the company had in use fourteen paddle tugs and ten eight-wire rope tugs, both classes being--owing to the state of trade--about equally short of work. The results of the working during these years were as follows:

================================================================ | | Freight | Cost of | Degree | | hauled | haulage in | of Class of tugs. | Year. | in | pence per | occupation. | | ton-miles. | ton-mile. | ---------------------------------------------------------------- Paddle | 1879 | 31,862,858 | 0.1272 | 0.686 " | 1880 | 31,467,422 | 0.1305 | 0.638 " | 1881 | 28,627,049 | 0.1245 | 0.537 Wire Rope | 1879 | 15,407,935 | 0.1167 | 0.614 " | 1880 | 17,289,706 | 0.1056 | 0.615 " | 1881 | 17,593,181 | 0.0893 | 0.536 ================================================================

The last column in the above tabular statement, headed "Degree of Occupation," may require some explanation. It is calculated on the assumption that a tug could do 3,000 hours of work per annum, and this is taken as the unit, the time of actual haulage being counted as full time, and of stoppages as half time. The expenses included in the statement of cost of haulage include all working expenses, repairs, general management, and depreciation. The accounts for 1882, which are not completely available at the time we are writing, show much better results than above recorded, there being a considerable reduction of cost, while the freight hauled amounted to a total of 54,921,965 ton-miles.

As regards the wear of the rope, we may state that the relaying of the first rope between St. Goar and Bingen was taken in hand in September, 1879, while that between Obercassel and Bingen was partially renewed the same year, the renewal being completed in May, 1880, after the rope had been in use since the beginning of 1876. The second rope between Bonn and Bingen, a length of 74¾ miles, is of galvanized wire, has now been 2¾ years in use, during which time there have been but three fractures. The first rope laid was not galvanized, and it suffered nine fractures during the first three years of its use. The first rope, we may mention, was laid in lengths of about a mile spliced together, while the present rope was supplied in long lengths of 7½ miles each, so that the number of splices is greatly reduced. According to the report of the company for the year 1880, the old rope when raised realizes about 16 per cent. of its original value, and allowing for this, it is calculated that an allowance of 18.7 per cent. per annum will cover the cost of rope depreciation and renewals. Altogether the results obtained on the Rhine show that in a rapid stream the economic performances of wire rope tugs compare most favorably with those of either paddle or screw tug boats, the more rapid the current to be contended against the greater being the advantage of the wire rope haulage.

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IMPROVED HAY-ROPE MACHINE.

Hay-ropes are used for many purposes, their principal use being in the foundry for core-making; but they also find a large application for packing ironmongery and furniture. The inventor is James Pollard, of the Atlas Foundry, Burnley.

The chief part of the mechanism is carried in an open frame, having journals attached to its two ends, which revolve in bearings. The frame is driven by the rope pulley. The journal at the left hand is hollow; the pinion upon it is stationary, being fixed to the bracket of bearing. The pinion gearing into it is therefore revolved by the revolution of the frame, and through the medium of bevel wheels actuates a transverse shaft, parallel to which rollers, and driven by wheels off it, is a double screw, which traverses a "builder" to and fro across the width of frame. The builder is merely the eye through which the band passes, and its office is to lay the band properly on the bobbin. The latter is turned to coil on the band by a pitch chain from the builder screw, the motion being given through a friction clutch, to allow for slip as the bobbin or coil gets larger, for obviously the bobbin as it gets larger is not required to turn so fast to coil up the band produced as when it is smaller. If the action is studied, it will be seen that the twist is put in between the bobbin and the hollow journal, and every revolution of the frame puts in one turn for the twist. The hay is fed to the machine through the hollow journal already mentioned. By suitably proportioning the speed of feed-rollers and the revolutions of the frame, which is easily accomplished by varying the wheels on the left hand of frame, bands of any degree of hardness or softness may be produced. The machine appears to be simple and not liable to get deranged. It may be after a little practice attended to by a laborer, and is claimed by its maker to be able to produce 400 yards of band per hour. The frame makes about 180 revolutions per minute, that is, this is the number of turns put into the twist in this time. The machine can make a bundle about 200 yards long, which can be removed off the bobbin without unwinding with the greatest facility.--_Mech. World._

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THE ANGLESEA BRIDGE, CORK.

The river Lee flows through the city of Cork in two branches, which diverge just above the city, and are reunited at the Custom House, the central portion of the city being situated upon an island between the two arms of the river, both of which are navigable for a short distance above the Custom House, and are lined with quays on each side for the accommodation of the shipping of the port.

The Anglesea bridge crosses the south arm of the river about a quarter of a mile above its junction with the northern branch, and forms the chief line of communication from the northern and central portions of the city to the railway termini and deep-water quays on the southern side of the river.

The new swing bridge occupies the site of an older structure which had been found inadequate to the requirements of the heavy and increasing traffic, and the foundations of the old piers having fallen into an insecure condition, the construction of a new opening bridge was taken in hand jointly by the Corporation and Harbor Commissioners of Cork.

The new bridge, which has recently been completed, is of a somewhat novel design, and the arrangement of the swing-span in particular presents some original and interesting features, which appear to have been dictated by a careful consideration of the existing local conditions and requirements.

On each side of the river, both above and below the bridge, the quays are ordinarily lined with vessels berthed alongside each of the quays, and as the river is rather narrow at this point, the line of fairway for vessels passing through the bridge is confined nearly to the center of the river. This consideration, together with some others connected with the proposed future deepening of the fairway, rendered it very desirable to locate the opening span nearly in the center of the river, as shown in the general plan of the situation, which we publish herewith. At the same time it was necessary to avoid any encroachment upon the width of the existing quays, which form important lines of communication for vehicular and passenger traffic along each side of the river, and to and from the railway stations. Again, it was necessary to preserve the full existing width of waterway in the river itself, which is sometimes subjected to heavy floods.

These considerations evidently precluded the construction of a central pier and double-armed swing bridge, and on the other hand they also precluded the construction of any solid masonry substructure for the turntable, either upon the quay or projected into the river. To meet these several conditions the bridge has been designed in the form of a three-span bridge, that is to say, it is only supported by the two abutments and two intermediate piers, each consisting of a pair of cast-iron cylinders or columns, as shown by the dotted circles upon the general plan.

The central opening is that which serves for the passage of vessels. The swing bridge extends over two openings, or from the north abutment to the southern pier, its center of revolution being situated over the center of the northern span, and revolves upon a turntable, which is carried upon a lower platform or frame of girders extending across the northern span of the bridge. The southern opening is spanned by an ordinary pair of lattice girders in line with the girders and superstructure of the swing bridge.

We propose at an early date to publish further details of this bridge, and the hydraulic machinery by which it is worked.

We present a perspective view of the bridge as seen from the entrance to the exhibition building, which is situated in close proximity to the southern end of the bridge.--_Engineering_.

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PORTABLE RAILWAYS.

[Footnote: Paper read before the Institution of Mechanical Engineers.]

By M. DECAUVILLE, Aîne, of Petit-Bourg (Seine and Oise), France.

Narrow gauge railways have been known for a very long time in Great Britain. The most familiar lines of this description are in Wales, and it is enough to instance the Festiniog Railway (2 feet gauge), which has been used for the carriage of passengers and goods for nearly half a century. The prosperous condition of this railway, which has been so successfully improved by Mr. James Spooner and his son, Mr. Charles Spooner, affords sufficient proof that narrow gauge railways are not only of great utility, but may be also very remunerative.

In Wales the first narrow gauge railway dates from 1832. It was constructed merely for the carriage of slates from Festiniog to Port-Madoc, and some years later another was built from the slate quarries at Penrhyn to the port of Bangor. As the tract of country traversed by the railways became richer by degrees, the idea was conceived of substituting locomotives for horses, and of adapting the line to the carriage of goods of all sorts, and finally of passengers also.

But these railways, although very economical, are at the same time very complicated in construction. Their arrangements are based upon the same principles as railways of the ordinary gauge, and are not by any means capable of being adapted to agriculture, to public works, or to any other purpose where the tracks are constantly liable to removal. These permanent narrow gauge lines, the laying of which demands the service of engineers, and the maintenance of which entails considerable expense, suggested to M. Decauville, Aîne, farmer and distiller at Petit-Bourg, near Paris, the idea of forming a system of railways composed entirely of metal, and capable of being readily laid. Cultivating one of the largest farms in the neighborhood of Paris, he contemplated at first nothing further than a farm railroad; and he contrived an extremely portable plant, adapted for clearing the land of beetroot, for spreading manure, and for the other needs of his farm.

From the beginning in his first railroads, the use of timber materials was rigidly rejected by him; and all parts, whether the straight or curved rails, crossings, turntables, etc., were formed of a single piece, and did not require any special workman to lay them down. By degrees he developed his system, and erected special workshops for the construction of his portable plant; making use of his farm, and some quarries of which he is possessed in the neighborhood, as experimental areas. At the present time this system of portable railways serves all the purposes of agriculture, of commerce, of manufactures, and even those of war.

Within so limited a space it would be impossible to give a detailed description of the rails and fastenings used in all these different modes of application. The object of this paper is rather to direct the attention of mechanical engineers to the various uses to which narrow gauge portable railways may be put, to the important saving of labor which is effected by their adoption, and to the ease with which they are worked.

The success of the Decauville railway has been so rapid and so great that many inventors have entered the same field, but they have almost all formed the idea of constructing the portable track with detachable sleepers. There are thus, at present, two systems of portable tracks: those in which the sleepers are capable of being detached, and those in which they are not so capable.

The portable track of the Decauville system is not capable of so coming apart. The steel rails and sleepers are riveted together, and form only one piece. The chief advantage of these railways is their great firmness; besides this, since the line has only to be laid on the surface just as it stands, there are not those costs of maintenance which become unavoidable with lines of which the sleepers are fixed by means of bolts, clamps, or other adjuncts, only too liable to be lost. Moreover, tracks which are not capable of separation are lighter and therefore more portable than those in which the sleepers are detachable.

With regard to sleepers, a distinction must be drawn between those which project beyond the rails and those which do not so project. M. Decauville has adopted the latter system, because it offers sufficient strength, while the lines are lighter and less cumbersome. Where at first he used flat iron sleepers, he now fits his lines with dished steel sleepers, in accordance with Figs. 1 and 2.

This sleeper presents very great stiffness, at the same time preserving its lightness; and the feature which specially distinguishes this railway from others of the same class is not only its extreme strength, but above all its solidity, which results from its bearing equally upon the ground by means of the rail base and of the sleepers.

In special cases, M. Decauville provides also railroads with projecting sleepers, whether of flat steel beaten out and rounded, or of channel iron; but the sleeper and the rail are always inseparable, so as not to lessen the strength, and also to facilitate the laying of the line. If the ground is too soft, the railway is supported by bowl sleepers of dished steel, Figs. 3 and 4, especially at the curves; but the necessity for using these is but seldom experienced. The sleepers are riveted cold. The rivets are of soft steel, and the pressure with which this riveting is effected is so intense that the sleepers cannot be separated from the rails, even after cutting off both heads of the rivets, unless by heavy blows of the hammer, the rivets being driven so thoroughly into the holes made in the rails and sleepers that they fill them up completely.

The jointing of the rails is excessively simple. The rail to the right hand is furnished with two fish-plates; that to the left with a small steel plate riveted underneath the rail and projecting 1¼ in. beyond it. It is only necessary to lay the lengths end to end with one another, making the rail which is furnished with the small plate lie between the two fish-plates, and the junction can at once be effected by fish-bolts. A single fish-bolt, passing through the holes in the fish-plates, and through an oval hole in the rail end, is sufficient for the purpose.

With this description of railway it does not matter whether the curves are to the right or to the left. The pair of rails are curved to a suitable radius, and can only need turning end for end to form a curve in the direction required. The rails weigh 9 lb., 14 lb., 19 lb., and 24 lb. per running yard, and are very similar to the rails used on the main railways of France, except that their base has a proportionally greater width. As to the strength of the rail, it is much greater in proportion to the load than would at first sight be thought; all narrow-gauge railways being formed on the principle of distributing the load over a large number of axles, and so reducing the amount on each wheel. For instance, the 9 lb. rail used for the portable railway easily bears a weight of half a ton for each pair of wheels.

The distance between the rails differs according to the purpose for which they are intended. The most usual gauges are 16in., 20 in., and 24in. The line of 16 in. gauge, with 9 lb. rails, although extremely light, is used very successfully in farming, and in the interior of workshops.

A length of 16 ft. 5 in. of 9 lb. steel rail, to 16 in. gauge, with sleepers, etc., scarcely weighs more than 1 cwt., and may therefore be readily carried by a man placing himself in the middle and taking a rail in each hand.

Those members of the Institution who recently visited the new port of Antwerp will recollect having seen there the portable railway which Messrs. Couvreux and Hersetit had in use; and as it was these works at the port of Antwerp that gave rise to the idea of this paper, it will be well to begin with a description of this style of contractor's plant.

The earth in such works may be shifted by hand, horsepower, or locomotive. For small works the railway of 16 in. gauge, with the 9 lb. rails, is commonly used, and the trucks carry double equilibrium tipping-boxes, containing 9 to 11 cubic feet. These wagons, having tipping-boxes without any mechanical appliances, are very serviceable; since the box, having neither door nor hinge, is not liable to need repairs.

This box keeps perfectly in equilibrium upon the most broken up roads. To tip it up to the right or the left, it must simply be pushed from the opposite side, and the contents are at once emptied clean out. In order that the bodies of the wagons may not touch at the top, when several are coupled together, each end of the wagon is furnished with a buffer, composed of a flat iron bar cranked, and furnished with a hanging hook.

Plant of this description is now being used in an important English undertaking at the port of Newhaven, where it is employed not only on the earthworks, but also for transporting the concrete manufactured with Mr. Carey's special concrete machine.

These little wagons, of from 9 to 11 cubic feet capacity, run along with the greatest ease, and a lad could propel one of them with its load for 300 yards at a cost of 3d. per cube yard. In earthworks the saving over the wheel-barrow is 80 per cent., for the cost of wagons propelled by hand comes to 0.1d. per cube yard, carried 10 yards, and to go this distance with a barrow costs ½d. A horse draws without difficulty, walking by the side of the line, a train of from eight to ten trucks on the level, or five on an incline of 7 per cent. (1 in 14).