In the heavy engines employed in transporting coal on the Reading Railway, and which burn anthracite coal, there are eight coupled wheels of 43 in. diameter, and the cylinders are 19 in. diameter and 22 in. stroke. The boiler is 46 in. diameter and contains 103 iron tubes, 24 in. external diameter and 14 feet long. The furnace is 7 ft. long, and the bars are cast in pairs and are made movable by a lever so that the clinker may be readily broken up. The ash pan is made to contain a few inches of water to prevent the bars from being burnt out. A good deal of the coal is said to be wasted in these engines from being carried up the chimney by the draught, and a good deal by falling through the bars of the grate. Upon the whole, anthracite coal cannot be said to have been very successfully introduced in locomotives. It is severe upon the furnace, and the evaporative efficacy reached does not appear to be more than 7 lbs. of water per pound of coal, which is a good deal less than is obtained with coke.

There are no buffers between the engine and tender of American locomotives, but a wedge is interposed between the abutting surfaces to obviate shocks. In the various carriages of the train, central buffers alone are used. The whistle is larger than that used on the English lines. Glass gauges are not found to stand, and four or five gauge cocks are employed. The feed pumps have air vessels both on the drawing and the forcing sides. The link motion is in universal use. The axle boxes are usually made close, and are supplied with oil, and provided with leather washers to keep the oil in. Slices of salt pork have been lately used for packing the axle boxes, and the result is stated to be satisfactory and economical. The boxes do not require to be packed or oiled more than once a month. The boxes are sometimes of bell metal, sometimes of a composition of 924 parts of zinc and 7 parts of copper, and sometimes are lined with, or wholly composed of soft metal.

To give toughness to the cast iron wheels, they require, after having been cast in a chill, to be annealed. The wheels, therefore, so soon as they are set, and while yet red hot, are transferred to pits which have been made very hot by anthracite fires. The pits are hermetically sealed, to prevent the admission of air, and after three days the wheels are taken out, when the annealing process is found to

E. Truck, or Bogie Frame, from the Centre of which the front part of Engine is supported. F. Lamp.

be completed. The annealing does not affect the chill of the tire, which is half an inch deep, as the operation of chilling takes place when the metal sets. It is necessary, however, with these chilled wheels, to be careful not to apply the brakes too suddenly, so as to occasion slipping on the rails, as the friction takes out the chill at that spot and causes a flat soft place to form on the wheel which destroys it altogether. Brake blocks of cast iron are used in some cases and are found to be preferable to wood. The brakes are set by winding a chain in connection with them on an upright barrel, having a hand wheel at the top. In cases of emergency, it has been proposed to work the brakes by a friction wheel, which may be instantly pressed down on the driving wheel of the engine. A cord is carried along the top of every carriage of the train to a large gong bell placed on the engine. This cord is formed in lengths equal to the length of a carriage, and the pieces are connected together by metal snaps. A small shaft led along the top of each carriage with square or triangular ends and sockets, and universal joints would be an equally simple arrangement. It is not found practically in America, that there is any trouble in connecting the cord to the new carriages when a change in the carriages takes place.

The American locomotive carriages are of much larger dimensions than those which are employed in this country. The bodies are commonly made about 45 ft. long, 9 ft. wide, and 7 ft. high. The carriages are open from end to end, and at the ends doors are placed, opening upon platforms protected by railings, and establishing a passage between one carriage and the next adjoining. From the platforms stairs descend, by means of which, passengers enter or leave the carriages. The seats are ranged on each side of a central passage, and the backs of the seats are made to turn either way. On the roof of the carriage ventilators are placed, and there is a stove to warm the carriage in winter and a supply of drinking water. To prevent the dust from rising, a canvass curtain has been introduced outside the wheels on some lines, extending from the carriage floor to the ground, whereby the dust is prevented from being sucked up by the motion of the train. In other cases jets of water propelled by a centrifugal pump, moved by a friction roller resting on one of the

wheels, have been introduced in an air space on each side of the carriage, through which the air is admitted; and the air is thus cooled and freed from dust by the same operation.

The carriage rests at each end on a truck or bogie with four wheels, and the wheels of each bogie are as far apart as the distance between the rails, so that the plan of such a truck forms a square. Indiarubber springs have been tried, but the result has not been satisfactory, and plate or volute springs are now usually employed.

In all the American locomotives, the internal fire box is considerably smaller at the top than the bottom, so that the sides are much inclined, whereby the escape of the steam from the surface of the metal is facilitated, and the overheating of the plate prevented. The fire boxes are almost universally of iron. The tubes of the boiler are generally of copper-few iron or brass tubes being in use, except that in engines using anthracite coal, iron tubes are used to diminish the wear caused by the hard particles of coal carried up by the draught, and which the copper cannot so well withstand. The general proportions of the American locomotives do not differ materially from those prevailing in England. On the whole, however, the blast pipes require to be smaller, and the draught more intense for engines burning wood, to maintain sufficient vividness of combustion; and the disposition now is to place the tubes farther apart than formerly. In some engines it has been found that an increased supply of steam was obtained by removing some of the central tubes, and the tubes are never placed closer than ths of an in. apart.

There is a separate blast pipe from each cylinder, and these pipes terminate at about the level of the lowest row of tubes. Suspended over these pipes, however, is a pipe called a "petticoat pipe," about 8 in. diameter, which reaches nearly to the base of the chimney, and this pipe being generally made conical, has a petticoat configuration. The object of this arrangement is to equalise the draught through the different rows of tubes, as when the blast pipe is carried up to the level of the top row of tubes the greatest draught will be through them.

ON THE ERECTION OF LOCOMOTIVES.

In erecting a 16 in. passenger engine at the Wolverton workshops, the boiler is first made, with the exception of the smoke box, which is left unfinished till the cylinders, which are of the class called inside cylinders, are fixed. The mode of procedure is then as follows: level the boiler both across and lengthways; draw a line on the bottom of the boiler, exactly in the centre, and from this line draw three more lines, one on the tube plate, another on the face of the fire box, and the third on the front of fire box. From these lines set off the centres and positions of all the brackets, cocks, &c. On the tube plate set off the holes for the cylinder ends, and the valve rod stuffing boxes, which have to be drilled out. On the face of the fire box set off points, which shall be prolongations of lines drawn through the centres of the cylinders, and if the cylinders come into their right positions, they must be made secure until the frames are fixed. In some workshops it is the practice to ascertain if the cylinders are in their right positions by means of a plank about of an in. thick, and 9 or 10 in. broad, except where it is made to fit accurately into the cylinders. The whole length of this board is a little more than the distance from the face of the fire-box to the bottom of the cylinders. This board traverses the axis of the cylinder, and it enables the parallelism of the cylinder, with the central line of the boiler to be at once ascertained, since the central line of the board will in such case come opposite to the point on the fire box, and by trying the board round in different positions, any divergence of the cylinder from the proper line can be readily discovered.

During the time occupied in fixing the cylinders, the motion plate and other brackets, ash pan, clack boxes, blow-off and gauge cocks, whistles, &c., may have been proceeded with. The frames which are supposed to be ready for being fixed, must now be got up and set to the proper distance horizontally from the face of cylinders or the valve ports, and care must be taken that they are set at right angles with the central line on the boiler, and also that their top edges are level. Meanwhile the regulator, handrail brackets, and other parts of the engine must be advanced towards completion. The frames in the case selected are of one-inch plate, welded into one

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solid piece. At first each frame consists of three pieces, and each piece is punched or slotted out to its proper shape, and all the holes which require to be left in it are drilled. The pieces are then laid on a level, with the centre line marked on each piece brought into its right position, and they are so retained during the welding process. The positions of the various points or centres are shown in the annexed diagram, fig. 472, in dotted lines. Kitson of Leeds has the

Fig. 472.

three rough pieces of the frame first welded together. The form of the frame is then drawn upon the rough plate, and the superfluous metal is then punched out by a machine provided with a proper table for facilitating the movement of such a large article. After two or three pairs of frames are thus punched, they are temporarily bolted together, and the edges are pared by a slotting machine with two moving heads. The guide blocks which are of wrought iron must then be fitted to the horn plates, great care being taken to place them at right angles with the frame, and to make them also in every respect of the same size, so that any box may, in case of accident, be transferred to another engine. Deficient accuracy in fitting the guide blocks at right angles with the frame is one main cause of the heating of the axles.

In the mean time the axle boxes should have been got ready for fitting into the slides. After the boxes have been cast, the first step is to fit the keep, which is generally made of cast iron. The boxes have then to be bored to suit the journals. They have next to be planed on the sides, and to this end two centres, one on either side, should be put in the hole of the axle box, which should then be laid on a surface plate, and, with the aid of a scribing block, the box should be set in such a position that the axis of the hole shall be parallel to the sides, and exactly in the centre of the box. The best way of treating the axle boxes after the holes have been bored out, is to have a mandril made to fill the hole, and it should form part of an L plate, so that it could be bolted to the planing machine table, and raised or depressed at pleasure. The box to be planed would be slipped upon the mandrel and set at the proper height, and when the tool got down to its proper distance from the table it would only have to be withdrawn, and the box turned over on the mandrel and planed down to the gauge. The only trouble in pursuing this course will be in setting the first box, but the time required for doing this will not materially exceed the time taken to set a box out in the ordinary The stud for holding the axle boxes may be made in this

manner.

shape,

and all the boxes required to be of the same size, will not require any setting, but simply fastening upon the stud, and will be sure to come from the machine with the axes of the hole parallel with the sides of the block.

In the early times of locomotive making, the common practice in boring out the axle boxes was, first to fit them in the horn plates, and then to bore them out in their places by means of a bar fitted with a cutter, which was driven either by hand or in any other convenient manner, and which was kept by wooden props or otherwise at right angles with the axes of the cylinders. In marine engines this course is still sometimes pursued, and in many workshops shafts are led! along the walls with appropriate pulleys, which, by means of a movable strap, will give motion to any pulley fixed on the end of

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the movable bar, employed to bore out any axle box or other bearing. In the case of locomotive axle boxes, however. this plan is abandoned, but the following modification of it is still very widely pursued: The axle boxes having been planed upon the sides and fitted into the slides, a shaft is put through the holes of the driving axle, and this shaft works in a socket, which, by means of four small screws, enables the shaft to be adjusted sideways, until it is brought exactly into the proper line the axle ought to occupy. A sharp pointed instrument or scriber is then placed in a hole, purposely formed to receive it in the shaft, and the shaft is turned slowly round, at the same time gently pressing the scriber up to the face of the box, when it describes a circle upon the outside of the box, slightly larger than the circle of the axle. A similar circle is then described upon the inside face of the axle box. Generally two shafts are employed at the same time, the position of the second shaft being adjusted from that one put through at the driving axle, and the circles proper for all the axles being described upon both faces of the several boxes by the aid of this apparatus, the boxes are removed from their places and bored out in a proper boring machine.

In boring the axle boxes in this manner there is some liability, unless great care is taken, of having them thicker on one side of the hole than at the other, and if it was required to introduce the boxes of any engine into another of the same class, which is sometimes required to be done when there are a number of engines in the workshops at the same time for various kinds of repairs, it may happen that the axle boxes are not such exact duplicates of one another as to enable this exchange to be effected without involving readjustments of the connecting rods, and even then the substitution would not be satisfactory. It is desirable, therefore, that all the axle boxes of each class of engine shall be precisely similar, and if care be taken in boring them in the manner described and in fitting the frames properly, no inconvenience from this cause need be apprehended.

The setting of the frames may be performed as follows:-Bolt them temporarily to the cylinder sides and fire box. At the fire box end wedges of hard wood may be interposed between the box side and frames, so as to keep them at the proper distance from the boiler until they are permanently fixed, when the wedges may be removed. The frames may be temporarily held together by long bolts passing from frame to frame. Place a centre point between the slides for receiving the axle boxes of each driving wheel.

The brackets for fixing and staying the frames must now be proceeded with, as also the motion plate, which both supports the guide bars and assists in supporting the frame. It is made of in. plate, with holes cut out for the eccentric and connecting rods to work through. It is fixed to the boiler by two 3 in. angle irons, bent to the sweep of the boiler, and going about one-third round, and riveted to the boiler within. rivets, at a pitch 24 in. apart. The plate is sometimes bolted to these angle iron brackets. There are stays, which pass from frame to frame, so as to make the whole more secure,-one immediately over the driving axle, and one at about 6 in. from the face of the fire box in the direction of the smoke box; also two others, one passing between the horn plates at the opposite sides of the engine at the trailing wheels, and the other at the leading wheels. The frames are also strengthened by the drag plates, which are of wrought iron, and which at this point of the construction may be attached. There is also a buffer plate, which passes from frame to frame, at the trailing end of the engine firmly riveted to the frame ends, with 3 in. angle irons and in. rivets.

The smoke box may now be fitted together, and the pistons tried into the cylinders, and the length of the piston rods tested, from side to side of the engine, so as to come exactly to the centres in the axle boxes, and if the straight edge cannot be put through the boxes, it may be placed in any other convenient position, plumbing down from the edge of the straight edge and from the centre of axle box on each side of the engine, and seeing that the two plumb lines on each side are the same distance asunder. A thin cord is now to be stretched beneath the boiler from the centre marked on the fire box to the centre marked on the tube plate, and a T or L square is to be applied so that one edge comes in the line of the straight edge in the axle boxes, and the other edge in the line of the cord stretched between the centres marked on the boiler, and the framing or the boiler is to

be so shifted that the cord and the edge of the square are out of winding with one another.

The position of the guide bars, as also of the reversing shaft, and of the brackets for the suspension links should now be determined, and those several parts should be fixed in their places. If the pistons are not ready at the time they are required, the guide bars may, nevertheless, be adjusted by setting them fair with a line passing through the centre of the cylinder. But it is the best plan to set them after the piston and piston rod have been inserted.* The cross head must be moved backwards and forwards, so as to see if the gland in the cylinder cover is free by raising or lowering the bars until that end is obtained. The gland should be an easy fit at every part of the stroke, but rather most so on the top side. The length of the inside connecting rod is got by setting the piston in the middle of its stroke, and measuring from the centre of the cross head shaft to the centre of the driving axle. It is usual to fix the pumps during the time that the valve gear is being fitted. The flanges by which the pumps are fixed are made a little thicker than is required for strength, so as to permit the pumps being properly set, without the flanges being too much weakened by accidental twists in the frame of the engine. The pump of a locomotive requires great care to fit it properly. The mode of procedure is as follows:-Cramp the pump to the frame side or motion plate, as the case may be. Place the ram and gland in, draw out the ram to its full stroke, and measure the distance at which it stands from the guide bars at both ends, and see how much it is from being parallel to the bars. If it be distant from the frame at the low end and at the other, then the amount to be chipped off the flange will be the difference between and 4, which is 4, multiplied by the total length of the pump, and that product divided by the length that the ram projected from the pump face. If this be chipped off, then the next time the pump is tried up it may be adjusted with little trouble. The wheels should now be placed under the engine. In some workshops there is a large travelling or other crane suited for lifting the engine, in which case the whole operation occupies about a couple of hours. Where there is no crane the engine is lifted by two screw jacks, applied alternately at each end of the locomotive. At the end of each lift a packing of wooden blocks is applied under the fire box at one end of the engine, and under the frames or cylinders at the other end, so as to prevent the engine from running down again when the screws are withdrawn. When the engine is raised to the requisite height, the wheels are run underneath it, and the operation of lowering is performed in the same manner as that of lifting, - the whole operation taking eight or ten hours, according to the number of men employed.

The next step is the setting of the valves. In the hole of the eccentric, place a centre, and draw a line passing through the two centres of the eccentric, that is the centre of the shaft and the centre of the eccentric pulley. Then draw another line parallel to the first, and distant the amount of lap and lead of the valve. From the point where this line cuts the circumference of the hole in the eccentric draw a line passing through the centre of the hole where the eccen tric is fixed on the shaft. When this last line is placed at right angles with the crank, the eccentric will have the required lead or advance of the crank. The length of the eccentric rods will be the distance from the centre of the die or block in the motion link when the valve is at half stroke, to the centre of the driving axle. When all the eccentric rods are on, the usual way of trying their length is to set the engine on the dead centres or at the ends of the stroke, and to see if the opening of the port is equal on both sides, or at each end of the stroke of the piston. If equal, the rods are of the correct length.

In trying the locomotive in the workshop under steam, it is usual to wedge the driving axle, by driving wedges between the bottom of the axle box and horn plate stay, and then to raise the whole engine upon the leading and trailing wheels, by means of wedges or packings inserted between the top of each box and the lower edge of the frame. In this manner the driving wheels are raised about 1 to 2 in. clear of the rails. Two wedges, with pointers in opposite directions

When the cylinders have inside covers the joints should now be made, for it is impos sible to make them when the guide bars are fixed without taking them down. The joint of the inside covers is made, generally, with red cement, but at some shops tallow is used for both the inside and outside cover, also the steam chest cover.

are drawn by two tie bolts under each of the leading and trailing wheels, which effectually locks the wheels, and prevents the engine from moving. When the outside rods are to be on the engine, it is generally entirely supported by the buffer beams resting upon solid packings of timber. Before lighting the fire care must be taken to see that all the check or split pins are in their places and are opened out, as serious results may arise from a bolt or pin working loose.

ON THE REPAIRS OF LOCOMOTIVES.

The general nature of the repairs of locomotives is the same in all classes of engines, but some forms of construction require much more frequent repairs than others. Some locomotives will run nine months before coming into the repair shops, and others only three months, although they are during this period taken into the running shed once or twice, and have the eccentric straps, inside and outside rods, and pistons and valves looked at and adjusted. The joints of the feed pipes very often require to be re made, which is done with wire gauze, lamp wick, and red lead. Some persons prefer canvas and cement. The steam chest and cylinder covers, and all the other large joints, when new and scraped to a fine surface, are made with tallow alone. When red lead is used to make the joints of the steam chest and cylinder covers, the surfaces soon become rough and uneven, thus rendering it necessary to place something more between the surfaces than red lead, and wire gauze is often used. Some persons make the joint.with red lead and tar band, which dries in. Others use cotton wick and red lead, which makes a better joint. The joints of the manhole, dome, and flange cocks, are usually made in the same way as the joints of the feed and steam pipes, namely, with wire gauze, lamp wick, and red lead, or cement and canvas.

The wheel tires and axle boxes are very troublesome parts of a locomotive and require frequent repair. The tires wear away rapidly at the flange, and the unequal wear of the tire on the circumference makes it of unequal diameter at different parts. The axle boxes wear in the slides and bearing, thereby giving the axles fore and aft and also end play, which greatly increases the instability of the engine. This evil is aggravated by the want of parallelism, which results from the unequal wear of the tires.

When an engine is brought into the workshop to undergo a thorough repair, a specification is drawn up by the engine driver and his fireman specifying the nature of the repairs required, but leaving it to the discretion of the foreman of the workshop to make such additional repairs as he may think advisable. The first operation is to have the engine wiped down, then it is lifted from the wheels either by screw jacks or by a travelling crane. The wheels having been rolled from under the engine, are sent forthwith to have new tires put on or the old ones turned should that be practicable, and refastened if they have worked loose. The engine is rested upon wooden blocks laid under the fire box and cylinders, or if the cylinders have to be taken down the blocks are then laid under the leading horn plates. Two men and a boy is the usual force employed to effect the repairs of an engine. If the cylinders have to be repaired, one man applies himself to the accomplishment of that part of the work while the other refaces the guide plates for the axle boxes. The connecting and eccentric rods with various parts of the rest of the valve motion are sent into the fitting shop to be there repaired. All the glands will generally require to be bushed anew and the cocks will require to have new plugs fitted or the old ones rectified. While the cylinders are off, the valve faces should be readjusted, and when the faces are worn very thin, new ones should be pinned on. These faces are sometimes of brass and sometimes of wrought iron or steel. In both cases they are fixed on by means of screws, diameter, having counter sunk necks.

In rejointing the cylinders together, the surfaces should both be first made true by the aid of a surface plate, by filing and scraping. Should the cylinders require to be bored out when they are taken down, this may be done by placing them in the boring lathe. But if the joints are in good condition and the cylinders require to be rebored without being removed from their places, the boring is accomplished by a portable boring machine consisting of a spindle fitted

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with a cutting bit. The spindle or boring bar is worked by means of suitable gearing, and is commonly turned by hand. One end of the spindle works in the piston stuffing box or gland and is guided by it. The block to which the cutting edge is attached is made to travel along the spindle by means of a screw let into a groove cut in the whole length of the spindle, and which screw is slowly turned round by suitable mechanism as in common boring mills. This machine may be moved to any point at which its services are required. When the cylinders are bored out, and thus rendered too thin, a liner of wrought iron is forged, and bored out and then turned on a mandril: it is made just to drive gently into the cylinder and stand flush with the end, so as to abut against the cover which holds it from moving; a couple of screws are also applied, one at either end screwed into the cylinder and heads counter sunk flush.

The guides for the axle boxes are filed according to the indications of a surface plate and worked square to each other. The boxes are found to acquire an amount of play fore and aft and end-ways ranging from1⁄2 to 4 full.

Before lining the axle boxes they should be put in their places, and lines should be drawn through the centres and trial be made to see if they are at right angles with the centre line upon the boiler, noting the side to which each packing has to be attached, to make the axle stand at right angles with the centre of the engine. The liners are invariably of brass, and are fastened in their places by brass or copper screws, screwed into the box and riveted at the other ends, forming deeply counter sunk heads. These liners should be planed or ground level on the side next to the box, and if the surface of the box has worked itself to an uneven surface, it should be planed previous to the application of the liner, so that the liner may bed well. The boxes should be a very good fit in the guides and should have no more freedom than that they can be just moved by a chisel bar. If they are allowed to pass with more play than this they will soon signify the defect by violent knocking and jolting. The bushes or bearings should be refitted with soft metal and fitted upon the journals. The frames should be minutely examined, both by the foreman and by the man who has charge of the engine, to see if there be any flaw discoverable, for the frame very often breaks in the middle of the fire box side, and across the driving horn plate. If a damaged part should be discovered a patch must be applied to it on both sides, if possible, such patch being well riveted with rivets, 읍 about 3 or 4 inches apart.

All the bolts in the frames and other parts of the engine should be examined, and those which are loose should be replaced by new The old bolts will be found in most cases to be almost cut in two. If the holes are out of shape they should be widened out and larger bolts should be inserted.

ones.

The stays of the fire box should be carefully examined, and if any of them have been leaking, which may easily be ascertained by observing the white mark left on the plate where the water or steam has oozed out, they must be drilled out. The heads may first be chipped off, and a small hole drilled in the centre of each faulty stay about inch deep and slightly squared out; and a square drift, or a piece of square iron, may then be inserted and the stay may thus be screwed out by the aid of a wrench.

The roof stays of the boiler should also be examined, and if any of the bolts have given way new ones may be introduced by screwing them in from the underside, or enlarging the hole, and driving up a bolt, with a copper washer between the head and plate, the other end being screwed for a nut. In both cases a loose collar should be placed between the edge of the stay and the fire box top. If there is room to put the bolts in from the top side it should be done so as to screw the nut on the end in the fire box, it being more easy to get at it when thus inserted.

The fire box will very often require repair at the corners and on the top of the shell immediately over the tube plate, and in case it cannot be got at to rivet a piece over the damaged part, a copper patch may be applied, fastened with copper screws, in. diameter, screwed into the boiler. The mud hole plugs should all be taken out, and if the threads on the plugs or in the holes are damaged the tap should be again inserted to repair the injury.

The pump clacks should be carefully examined; if requisite, should

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be turned up anew and reground in, and the feed and steam pipe should be examined, and if necessary remade.

The whistle, pressure gauge, and water gauges, should all be examined. The guide bars should be straightened and faced up, when they may be adjusted in the usual manner. The eccentric straps should be refitted on the eccentrics. The eccentrics themselves should be looked to, and if loose, new keys should be added or a set screw be introduced where there is none. Sometimes the lead of the eccentrics requires to be altered, when of course, the key has to be removed and a new one inserted; and the key bed must either be altered to suit the alteration, or a new key has to be fitted of the form proper to fit the key bed, when the bed in the eccentric and axle are no longer opposite one another. The eccentric rods when connected to the eccentric hoop by palms and bolts, are lengthened by inserting plates between the palm; and when the rod and hoop are in one, the rods are lengthened by being drawn. The connecting rods are altered in length by introducing packings behind the brasses, and by taking off or adding to the breadth of the cutter when that change is allowed by the nature of the rod ends; but where this is not practicable, the rods are lengthened or shortened by being drawn or staved, and the surfaces are again polished by being ground. If a crank should happen to be broken and has to be taken out, it should be well fastened together by plates and bolts before lifting the engine. The cranks generally break in the corner of the web. To prevent this, wrought iron straps 1 inch thick, and 3 inches broad are shrunk on, and the strength of the cranks is thus much increased.

With respect to the durability of the valves of locomotives and the manner in which they give way, the following facts have been furnished to us as the results of an extended experience:

"We find them broken in the root of the bend close to the buckle, and in some instances across the corners of the buckle. The size of valves for goods engines runs as shown in fig. 474. Lap 1 in. We set them with inch lead full port, at full throw of eccentric.

Fig. 474.

“I have never known the valve spindle to break, unless the valve has broken and stuck in the ports, but I have known the spindle to bend without the valve breaking. The length of time run by valves before being replaced by new ones is, in Wilson's engines, 12 months, but they require facing up every time they come into the shop, which is about every

six months. The faults of those valves and cylinders consist in being too soft.

66

'Stephenson's engines run about four years, and I have known them run as long as seven years. They are the best cylinders we have the metal is so hard that a file will scarcely touch it. The length of time run depends entirely upon the quality of the metal. I should imagine that the quality of the water used for evaporation, will also have an influence on the wear of the valve and seatings.

"In working a locomotive it is found that the eccentric rods get out of set, so as to throw a side strain on the link motion and the valve spindle, the latter being pressed against the gland on one side, producing great friction and heat, which may cause the spindle to bend, or it may be bent by the steam chest getting filled with water, from neglect in not opening the waste water cock; but I think the former cause is the most frequent.

"In an experiment I made, in 1856, on a valve frame or spindle 11 diameter, with the end which fits in the socket or cross head 14 inch diameter, socket 24 diameter, and thickness of cutter in., the spindle was suspended by the buckle, and the socket was loaded with a weight of 11 tons, which sheared the cutter, the spindle not sustaining any injury. Another cutter of the same dimensions, but tempered, was bent with a weight of 11 tons. All the valve spindles of the kind just referred to, and as made by Kitson of Leeds, break at the cutter."

It will not be expected that, in the limits to which these remarks must be restricted, we should be able to go into every detail connected with the locomotive engine. But in the foregoing exposition we do not know that we have omitted any point that is material. In the application of steel, instead of iron, in the construction of the engine and boiler, a considerable reduction of the weight may fairly be expected. Nevertheless it must not be supposed that the manufacture of steel has yet reached such a state of perfection as to enable it to be employed with perfect confidence, and some steel boilers have notoriously been failures. The surcharging of the steam is, in the present state of the matter, an improvement of doubtful advantage. But it is important to keep the cylinders very hot, and to heat the feed water to the boiling point by the waste steam, or otherwise, before it enters the boiler. As regards smoke burning, none of the plans yet introduced can be said to be successful, and the best expedient at present seems to be the use of coke and anthracite coal mixed in suitable proportions.