THE WESTINGHOUSE AUTOMATIC AIR BRAKE.

Figs. 3342, 3343 and 3344 represent the Westinghouse automatic air brake applied to an engine and tender, and in the following figures details of the construction of various parts are shown.

The pump governor, which is shown at g in Fig. 3326, of a modern freight locomotive, is shown in section in Fig. 3345.

The pump governor is employed for the purpose of cutting off the supply of steam to the pump when the air pressure in the train pipe exceeds a certain limit, say 70 lbs. per square inch.

Its operation is as follows:

When valve 10 is (by means of hand wheel 8) screwed home to its seat the steam is entirely shut off from the steam cylinder, but by operating wheel 8 to unscrew spindle 9, valve 10 is permitted to open and let the steam pass through a and b to the steam cylinder which operates, forcing air into the reservoir and thence into the train pipe. A pipe from the train pipe connects to the upper end of the pump governor, hence air from the train pipe passes around the stem 14 to the upper side of the thin diaphragm 18, which is held in its position by the spring 12 with a force sufficient to enable it to resist, without moving, a pressure of 70 lbs. per square inch. But when the pressure exceeds 70 lbs. per square inch it forces the diaphragm down, pushing down valve 13 and allowing the steam in a to pass up through valve 13 and out of the exhaust pipe 6. The steam pressure in a being thus reduced, that in b acts on the under side of the valve, causing it to rise and seat itself and thus cut off the supply of steam to the pump.When the pressure in the train pipe is diminished by the brakes being applied, the diaphragm is restored to the position it occupies in the figure by the action of the spring 16. Then valve 13 is seated by the spring 12, and the steam pressure accumulates on the upper end of valve 10, forcing it down and letting the steam from a into b and thence into the steam cylinder, starting it into action, which continues until the pressure in the train pipe exceeds 70 lbs. per square inch.

The use of this governor not only prevents the carrying of an excessive air pressure in the train pipe, which may result in entirely preventing the wheels from revolving and causing a flat place to wear on the wheel tire, but it also causes the accumulation of a surplus of air pressure in the main reservoir, while the brakes are applied, which insures the release of the brakes without delay. It also obviates the unnecessary working of the pump when the desired air pressure has been obtained.

A sectional view of the steam and air cylinders is shown in Fig. 3346, the construction being as follows:

Steam is distributed to the steam cylinder by means of a piston valve, composed of three pistons, marked 16, 14, and 20 respectively, the steam entering between pistons 16 and 14, and, in the positions in which the parts occupy in the figure, steam can pass through the bushing 18 and beneath the steam piston 7, propelling it upwards until the bottom of the hole in its piston rod strikes the end of rod 12, and raises it and valve 13. The chamber 23, in which valve 13 works, receives steam through a suitable port from the steam space between valves 14 and 16; and the steam from chamber 23, it is that (in the positions the parts occupy in the figure), acting on the area of the large valve piston 20, holds the valve down against the pressure on the bottom face of piston 14 of the valve. As soon, however, as the piston rod 7 strikes and raises rod 12 and valve 13, the steam is exhausted from the top of piston 20 of the valve, and the steam beneath piston 14 of the valve raises the valve, opening the lower port in the sleeve 18 for the exhaust, and piston 14 admits steam to the upper side of the steam piston 7. The construction of the air cylinder differs somewhat from that shown in the freight locomotive, Fig. 3326, this air pump corresponding with that shown on the engine and tender, Fig. 3342. A detail list of the parts may be given as follows:

A side view of the driving wheel brakes is shown in Fig. 3347 and an end view in Fig. 3348. The brakes are, it is seen, suspended by links so that their weight tends to keep them from the wheels. The brake piston rod carries at its end two links which attach to the arms attached to the brakes. The ends of these arms being curved roll together, the arrangement forming in effect a rolling toggle joint. The construction of the piston of the driving wheel brake is shown in Fig. 3349. The piston is made air tight by leather packing indicated by 11, held out by a spring 12. The piston rod packing, 7, is leather held in place by the cap 6 and the spring 8. The air for operating the brake enters below the piston.

LOCOMOTIVE RUNNING.

The engineer’s duty in running a locomotive is more arduous and requires more watchfulness than any other engine running, because of the peculiarities attending it. In the first place, the jolts and jars to which the engine is subject are liable to cause nuts, pins, etc., to come loose, and some of the parts to become disconnected and cause a breakdown of the engine.

This renders necessary a careful examination of the engine, which should be made both before and after each trip.

In the second place, we have that the amount of load the engine has to pull varies with every varying grade in the railroad track, and the variation is so great that on some descending grades the engine may require no steam whatever, while on ascending grades the utmost power attainable from the engine may be required. In firing, feeding the pumps, oiling the parts, and determining the depth of water in the boiler, the grade and the length of each grade has an important bearing, and so has the weather, since it is clear that between the heat of summer and the blizzards of winter there is a wide range of the conditions under which the engine runs.

In former times, from the less perfect construction of locomotives, the engineer’s duties were greatly enhanced from breakdowns, which are comparatively rare with modern locomotives, and there is promise that from improved construction and safeguards they will become less frequent in the future.

It is as important for the locomotive engineer to be familiar with the track as it is to be with the engine, and there is no field of engine driving or running in which more scope is permitted to the engineer to exercise judgment and skill in his management, so as to effect economy in fuel consumption.

The quality and size of the coal is another element that requires attention and observation on the part of the engineer, in order that his train may keep its time and the fuel consumption be kept down.

GETTING THE ENGINE READY.

The first thing to be done in getting ready for a trip is to see that there is sufficient water in the boiler, so that if there is not, there is time to supply the deficiency.

If the boiler is cold it may be that the condensation of the steam in cooling may have left a partial vacuum in the boiler, and it will be necessary in that case to open the top gauge cock and let in air so that the water will come to its proper level in the gauge glass. Similarly, in filling the boiler, it may be necessary to open a gauge cock to let the air out.

The lower cock of the gauge glass should be opened to let the steam blow through if there is pressure on the boiler, or to let a little water out if there is not.

The safety valve should next be examined and moved to see that it works properly and does not stick to its seat.

Before laying the fire the fire bars and ash pan should be cleared of ashes and clinkers, and the grate bars tried with the shaking levers to see that the grates will shake properly. It should be seen that the tubes, etc., are clear of ashes.

In laying a new fire an ample supply of lighting material should be used, disposing it so that the fire will light evenly and not in spots, and a good layer of wood should be evenly distributed over the bars, the thinnest pieces being at the bottom as they will light easiest, and it is necessary to light the fire at the bottom, so that the heat from the wood that is first lighted shall pass through that to be lighted.

The wood should be kept burning without coal until the lower stratum has ceased to blaze and covers the bars, while there is an even layer of blazing wood above it.

The quantity of coal to be fed at a time, and the depth of fire to be kept, depends upon the size of the coal, because the larger the coal the less it obstructs the draught, and the thicker the layer required in order to prevent currents of air from passing through without entering into combination with the gases from the coal.

If the coal is mixed, containing large lumps, they should be broken.

The first layer of coal should be enough to cover the fire to a depth of about two inches, which will permit of a good draught. This will get well alight while the wood is still serviceable, and a second layer may be applied of another two inches. The third feeding should be given with a view to have a greater depth of fire at the sides than at the middle of the fire box, because the cool sides of the box prevent perfect combustion, and currents of cold air are more apt to find their way through the sides than in the middle of the fire box.

Banking a fire consists of piling it up at the back half of the fire box and covering it up with green coal, so that it may keep alight and keep the boiler hot without increasing the steam pressure.

The air passing through the uncovered half of the fire bars prevents rapid combustion and a dead fire is maintained.

In starting up a banked fire, the first thing to do is to clean it of ashes, clinker, etc., shaking up the bars to see that they will work properly. The fire is then spread evenly over the bars, and wood fed to enliven the fire and promote the draught.

The blower or blast pipe is then set going, and coal gradually fed a little at a time, evenly distributed, covering those parts the most where the fire burns through the most brightly.

A steady fire is better than one that is forced, because the combustion is more perfect and less clinker is formed, hence less cleaning will be necessary, and the fire door will not be kept open so long to let in cold air. This is important because a steady temperature in the fire box promotes its durability, as well as giving a uniform boiler pressure. The strains placed upon a fire box by a fierce fire suddenly cooled by a heavy charge of coal or of cold air from an open fire door are highly destructive.

Furthermore, the greatest economy of fuel is attained by keeping the boiler pressure up, and using the steam expansively by hooking up the links to shorten the point of cut-off.

A safety valve steadily blowing off steam, whether the engine is running or not, is a sign of bad firing and wastefulness.

It is the fireman’s duty to attend to the fire, but nevertheless a careful engineer will be as much interested in proper firing as in his own duties, and as the engineer has more experience than the fireman, he is warranted in exercising an ordinary supervision on the firing, which will be welcome to an earnest or ambitious fireman.

The engineer should examine, with a wrench in hand, the bolts and nuts about the trucks and axle boxes, as these are apt to become loose and come off on the road. A proper construction would remedy this defect almost entirely, and by a proper construction is meant the more frequent employment of split pins, cotters, and other similar safety appliances now omitted for the sake of economy of manufacture.

Nothing in the future of the locomotive is more certain than improvement in this respect, and nothing is more urgently needed, as any engineer will become satisfied if he will gather up along a mile of ordinary railroad the nuts and washers that lay along the track.

The eccentric straps and the pins in the link motion require an examination, which may be done while oiling the parts of the engine.

The oiling requires careful attention; first the cups themselves sometimes become loose, an argument in favor of having, wherever possible, the cups solid on the parts, as done in European practice.

Oil holes are apt to get choked by gumming, which is that the oil in time forms into a brown gummy substance that fills the oil hole. Perfect lubrication does not imply wasteful lubrication by any means, but a wasteful use of oil is probably less expensive than insufficient lubrication.

A thorough engineer will use no more oil than is necessary; he will leave nothing to conjecture or chance, but know from personal inspection that his engine is in complete working order, and to this end the lubrication of the working parts is a vital element.

After having oiled the eccentric straps, the link motion and the reversing gear beneath the engine, the reversing lever and the parts above the frame must be oiled, and the reversing lever moved back and forth several times, from end to end of the sector or quadrant, so as to distribute the oil throughout the joints and working surfaces.

The axle boxes require careful attention in oiling. In English practice, tallow is packed in the corners of the cavities of the top of the box, so that if the box should begin to heat the tallow will melt, and afford extra lubrication with a heavier lubricant than usual, which will often stop the heating.

The connecting and coupling rods then require attention, the cups being filled and the lubrication adjusted.

When steam is up the gauge glass should be blown through again, and it will be found that the water stands higher in the glass than it did before the boiler was under pressure.

The packing of the piston and of the pump glands, if the engine has pumps, should be known to be properly set up, bearing in mind that a leaky pump gland lets air into the pump and impairs its action.

The sand box should contain dry sand, as wet sand will not feed properly.

If steam is raising too rapidly, close the lower damper to reduce the consumption of fuel and save blowing off steam through the safety valve, which should always be avoided as much as possible.

Before starting the engine, open the cylinder cocks and keep them open until the sound discloses that dry steam, and not steam and water, is issuing.

Open the throttle enough to start the engine easily and not with a jump, and be prepared to shut off steam instantly if a blow in any part of the engine should indicate an obstruction to its working.

In starting a train, the reversing lever is put in the end forward notch and the cylinder cocks opened. Then the throttle is opened a little at first, so as to avoid starting with a violent shock that might break the couplings.

If in starting (or in ascending gradients) the wheels are forced to slip, the sand lever should be operated, a slight sprinkling of sand serving better than a heavy one. If the sand is damp, it will fall in lumps and not distribute evenly as it should do, while at the same time a great deal more sand will be found necessary.

When the train is fairly under way, the aim should be to maintain full boiler pressure, so as to keep up the required speed with the links hooked up to work the steam as expansively as possible, bearing in mind that the higher up the links are hooked the more expansively the steam is used, and that therefore less steam is used to do the work and the boiler pressure can be kept up easier.

To understand this clearly, let it be supposed that the steam pressure in the boiler is 90 lbs. per square inch, and that the piston area is 400 inches, and the total pressure impelling the piston will be 36,000 lbs.; if this follows the piston for 22 inches, the power becomes 792,000 inch lbs. per stroke.

Now suppose the pressure is 150 lbs. per square inch, and this multiplied by the piston area (400) gives 60,000 lbs. impelling the piston, and this would require to follow the piston but 13.2 inches in order to give 792,000 inch lbs. In the one case we have 22 inches, and in the other 13.2 inches of the cylinder to fill with steam. Of course it will take more fuel under the heat of firing to keep the pressure up to the 150 lbs.; but on the other hand, when the steam is cut off in the cylinder there will be 160 lbs. per square inch in it, and all the work that this does in expanding is gained during the rest of the stroke, so that the required amount of power would be obtained by cutting off earlier than at 13 inches.

The water should, under ordinary conditions, be kept at an uniform level in the boiler. Steam can of course be made quicker with a small than with a large quantity of water, but the smaller the quantity of water the more the steam pressure is liable to fluctuate, and the closer the firing must be attended to.

Furthermore, the more water there is in the boiler, the greater the safety, because the longer the boiler can go without feeding, and, if the pumps or injectors, as the case may be, should act imperfectly, there is more time to get them working properly.

In testing the water level, the gauge glass alone is not to be entirely depended upon, hence the gauge cocks should be opened. The water should not be allowed to go below the middle gauge cock.

It is obvious that when the water is below a certain gauge cock, the gauge glass only can give any information as to how far it is below it, hence it must be used for this purpose.

When using it, it should be blown through by opening its lower cock, and if there is any doubt about its showing the proper water level it should be blown through two or three times, watching the level of the water in the glass at each trial.

A constant boiler feeding is the best, as it is more conducive to a uniform boiler pressure and temperature.

The fire should be fed in small charges, the fire door being kept open as little as possible, because a high temperature in the firebox is necessary to perfect combustion. If heavy charges of coal are given at once, then for some time the fire box will be cooled, and then, as the fire burns through, a fierce heat will be generated. This alternate heating and cooling is very destructive to the fire box and the tubes, as it causes an expansion and contraction that rack the joints and seams.

There are several ways of firing, each having its advocate. Upon the following points, however, there is no dispute. First, a slow combustion is the most perfect, because it produces less clinker, which saves fuel and also saves a large amount of fire cleaning and therefore of admission of cold air to the fire box. A high temperature is necessary to combustion, and the temperature of the fuel is most difficult to keep up at the sides of the fire box.

By light and frequent firing the bright fire will never be covered up, hence the temperature will be maintained. This favors an even distribution over a large surface of the fire of each shovelful of coal. But if at any point the draught is lifting the fire, and small bright pieces of fire are lifting up, it is an evidence that the fire is thinnest there or else that the bars are cleanest there. In either case, an extra amount of coal is required at that spot.

Some engineers will charge one side of the fire box lightly and then the other, this being done so as to keep up the temperature in the fire box. Others will fire first the front and then the back of the box, which answers the same purpose, but in no case should the charge be heavy.

A fireman may become so accustomed to the road and his engine, that under some conditions he may fire when he reaches certain points on the road, regulating it like clockwork.

On a trip from Philadelphia to Reading, on an engine having a Wooten fire box (whose special feature is a large fire box, which enables slow combustion), the firing was conducted as follows:

The fire was was not fed or touched until just before reaching Bridgeport, 18 miles from Philadelphia, when a thin layer of coal was spread evenly on the fire. Eleven miles were then made without opening the fire door, the next firing taking place just before reaching Phoenixville.

Ten miles were run before the next firing, which occurred just before arriving at Pottstown.

The next firing occurred at Bordenboro’, three miles from Pottstown. The remaining 8 miles were made without firing. The steam pressure did not vary more than 10 lbs. per square inch during the trip.

On a trip from New York to Philadelphia by the lightning express train the firing was conducted as follows:

The coal was anthracite and in lumps from 5 to 7 inches in diameter; at one end it reached up to the level of the fire door, while at the tube plate end of the fire box it was about 6 inches deep.

The grate bars were constructed to shake in three sections, and shaking the bars to clear out the fire caused it to feed forward of itself, and the combustion of the coal caused it to break up into lumps about 2 inches in diameter at the tube plate, where the fire was much brighter than at the fire door end. The steam pressure varied about 10 lbs. during the trip.

We now come to the best times to fire, to feed, and to oil the valves, and this depends on the level of the road.

On a level road these matters could be attended to with regularity, but as the engine has most work to do in ascending inclines, it is necessary to prepare for such emergencies: First, by having a good fire prepared, so that the fire door may be kept closed as much as possible while the engine is ascending; second, by having plenty of water in the boiler, so as to keep steam, without feeding any more than possible when the engine is calling for more steam, by reason of the reversing lever being put over towards full gear.

The speed is kept well up before reaching the incline, and the reversing lever moved forward a notch or two at a time to maintain the speed, while at the same time moving the sand lever to feed the sand as soon as the engine speed shows signs of reducing.

ACCIDENTS ON THE ROAD.

The accidents to which the locomotive is most liable when running upon the road, and the course to be pursued by the engineer to enable him to take the engine to the depot or complete the trip, are as follows:

Knocking out the Front Cylinder Head or Cover.—This arises from various causes, such as a breakage of a connecting rod strap, or of a piston rod or cross head. It is the practice of some locomotive builders to cut in the cylinder cover flange a small groove close to the part that fits the cylinder bore, so that the cover shall break out in the form of a disc, leaving the cover, flange, bolts, and nuts intact, and diminishing the liability to break the cylinder itself as well as the cover.The provisional remedy for this accident is to take off the connecting rod (on the side of the broken cover) and also the valve motion, either at the rock shaft arm or by taking down the eccentric rod straps. Then place the valve in the centre of its travel so that it shall cover and enclose both the cylinder steam ports and leave the exhaust port open. Then block the cross head firmly on the forward centre, and go ahead with the other cylinder.

Heating of Piston Rods.—This the engineer can often discover by sight, or by smelling it from the cab. The remedy is to stop the engine and slack back the gland until the steam from the engine cylinder leaks freely through the packing. Then apply a little extra lubrication or water while running slowly.

Breaking of a Piston Rod.—If the piston rod breaks, but does not knock out the cylinder head or cover, pursue the same course as directed for breaking the cylinder cover, taking the additional precaution to block the piston, which may be done by fitting pieces of wood between the guide bars, making the pieces long enough to fit between the cross head and guide yoke.

The cylinder or waste water cocks on the side of the accident must also be opened, to prevent any leakage of steam past the slide valve from getting into the cylinder and driving the piston against the cylinder cover, and breaking the cylinder cover or even the cylinder itself.

If the piston rod breaks from the cross head, it is safest to remove it from the cylinder, though this is unnecessary, if it be securely blocked against the cylinder head so that it cannot move, though steam may leak in on either side of it.

Breaking a Crank Pin.—This is a somewhat frequent accident, but seldom takes place on both sides of the engine at once.

The remedy is to take off all the parallel or coupling rods, and if it is the crank pin on the driving wheels which breaks, take off the connecting rod also, and securely block the cross head, disconnecting the valve motion as before directed, and opening the cylinder waste water cocks. In the case of this accident occurring, it is absolutely essential to take off the parallel rods on both sides of the engine, or otherwise the crank pins on the other side are apt to break.

Throwing Off a Wheel Tire.—In this case the best plan is to block the tireless wheel entirely clear of the track, which may be done by putting a block of wood into the oil cellar of the driving box, and then tow the engine to the repair shop; for if the engine is run to the shop, and the wheel touches the rail, it will impair its diameter for the proper size of tire.

Throwing Off a Driving Wheel.—This is not a common accident, but nevertheless it sometimes occurs; they break usually just outside of the driving axle box. In this case take out the driving box and fit in its place a block of wood affording journal bearing for the axle. Let this block rest on the pedestal cap, holding the axle up in the centre of the pedestal. Then secure the piston and disconnect the valve gearing and open the cylinder cocks as before, and the engine can be run slowly to the repair shop without danger of further accident, or, if convenient, it can be towed by another engine.

Breaking a Spring Or Spring Hanger.—Lift the engine with the jacks until the driving wheel axle box is about in the centre of the pedestal, and put any convenient piece of iron across the top of the driving axle box and between it and the engine frame, thus taking the weight of the engine on the frame instead of on the spring. Place also a block of iron between the end of the equalizing bar and the top of the engine frame, so as to prevent the movement of the equalizing bar, and to allow the spring at the other end of the equalizing bar to operate without moving the said bar. Every engineer should carry in his tool box pieces of metal suitable for this purpose, because this is a frequent accident. It does not, however, materially affect the working of the engine, and should not delay a train more than a few minutes.

Bursted Flues and Tubes.—These are usually plugged by tapering a piece of pine wood and driving it into the bursted tube by means of an iron bar. Taper iron plugs are often carried, and then driven into the end of the tube after the wooden one has been driven in. To enable this job to be done, it is necessary to thickly cover the fire with green coal, which operates to cool the tubes and prevent the loss of the water in the boiler. Sometimes careful engineers prepare for use pine plugs turned slightly taper, and a little slack, for the inside of the tube. In case of leak, this plug is inserted in the flue, and driven along it until it covers the fracture, the expansion due to its saturation causing it to become locked in the tube.

Slipping of Eccentrics.—Place the reverse lever in the forward notch of the sector. Place the crank on its forward dead centre, as near as can be judged by the eye, and loosen the set screw of the forward eccentric, that is to say, the eccentric which connects to the upper end of the link. Move that eccentric round upon the axle until the slide valve leaves the steam port at the front end of the cylinder open to the amount of required valve lead. In moving the eccentric round upon the shaft, move it in the direction in which it will rotate when the engine is running forward, so as to allow for and take up any lost motion there may be in the eccentric straps, in the eccentric rod eyes and bolts, and in the other working parts of the valve gear; for if the eccentric was moved backward, all such lost motion would operate to vitiate the set of the valve. The eccentric being placed as directed fastens its set screw securely.

If the backward eccentric is the loose one, throw the reverse lever to the backward notch of the sector, lifting the link up so that the eccentric connected to the lower end of the link may be approximately adjusted by moving it around upon the axle in the direction in which it will rotate when the engine is running backward, until the back cylinder port is open to the amount of the valve lead. Another very ready plan of temporarily adjusting the eccentrics is as follows: Place the reverse lever in the end notch forward, and place the engine crank or driving crank pin as near on a dead centre as the eye will direct, and open both the cylinder waste water cocks. Then disconnect the slide valve spindle from the rocker arm, and move the slide valve spindle until the opening of the cylinder steam port corresponding to the end of the cylinder at which the piston stands will be shown by steam blowing through the waste water cock at that end of the cylinder; the throttle valve being opened but a trifle, to allow a small steam supply to enter the steam chest and cylinder, for if much steam is admitted, it may pass through a leak in the piston and blow through both the waste water cylinder cocks.

The position of the valve being thus determined, the eccentric must be moved upon the driving axle until the valve spindle will connect with the rocker arm without being moved, or moving the valve at all.

Hot Axle Boxes.—If not convenient to reduce the speed of the engine, or if that and free lubrication do not cool the box, a plentiful supply of cold water should be administered, it being well to have at hand a small hose pipe, by means of which water from the tender tank can be used. If the brasses have Babbitt metal in them and it should melt, it is better, if possible, to cool the axle box while the engine is moving, which will injure the journal less than if the journal is stopped to cool the box, because in the latter case the brass or box is apt to become soldered to the journal of the axle, and when the engine is again started, the cutting or abrasion will recommence with extreme violence.

Breaking a Lifting Link Or the Saddle Pin That Connects The Slot Link To the Reverse Shaft.—Cut a piece of wood and tie it into the slot of the link, over the link block or die, making it of a length to keep the link in the position for hauling the train. Then fasten another piece of wood in the link slot beneath the sliding block or die, thus securing that die in the proper position for the engine to go ahead. In this case, the engineer must be careful in stopping, as he cannot reverse the engine on the crippled side.

Secondary accidents are almost sure to occur if a disconnected piston is not securely blocked in the cylinder, or from blocking the piston aright and attempting to let the slide valve run, or from attempting to run with the parallel rods on one side only disconnected. There are numerous accidents, which only common sense and a familiarity with the locomotive can provide a temporary remedy for, but those here enumerated are by far the most common.