A tube 2 inches in diameter and 12 feet long would have the following surface: Multiply the diameter 2 by the fixed number 3.1416 which equals 6.2832, and this multiplied by the length of the flue in inches, which is 144, equals 904 plus square inches. A flue 4 inches in diameter would have twice that surface, or 1,808 plus square inches, but the 4-inch tube occupies the space of four 2-inch tubes and there would be a loss of heating surface of the difference between 3,616 plus (equals 4× 904 plus) and 1.808 plus, the surface of the 4-inch tube, or a loss of 1,808 plus square inches of heating surface.

While the blaze does not live long after entering the flues the heat that is passing through them to the atmosphere, and which otherwise would be a total loss, by this means is largely utilized. The feed water entering the boiler at the boiler checks near the front end of the boiler, and while warmed a certain degree by the steam from the boiler uniting with it, is still lower in temperature than the gases passing through the flues and it absorbs their heat as they pass each other. The water as it passes back toward the firebox continues to absorb heat from the escaping gases in the tubes and grows hotter and hotter until when it reaches the sheets where it will be subjected to the greatest amount of heat it is almost ready to be converted into steam, and it does not cool the sheets that are in direct contact with the fire as it would if the water was passed from the tank directly to the rear portion of the boiler.

If one could see the interior of a locomotive boiler when a heavy demand was being made on its steam furnishing capacity the sight would be one to be remembered. There would be the solid body of water at the front of the boiler gradually growing warmer and expanding in response to the heat it had absorbed, and next to the firebox would be a great mass of seething bubbles exploding constantly into the invisible vapor, which is ordinarily denoted as steam, and rising to the top of the boiler to pass out and do the work for which it had been created. Like the interior of the firebox the change would be constant and rapid.

To meet the increased demand of combustion to supply larger cylinders the question of increased grate area has received much attention from locomotive designers and builders. It was recognized that the deep box between the frames had

grate surface could not be increased any farther in that direction. The shallow box had reached the limit of width and length, and what is commonly spoken of as the trailer, or a locomotive with a small independent driver or enlarged truck wheel, whichever you choose to call it, over which the firebox may extend has been the result of this consideration. This gives the extra needed grate surface and in this type of engine the fire is brought much closer to the tubes and crown sheet than in the deep box and, therefore, other things being equal, they should have better steaming qualities and undoubtedly do, when one considers the extra demand made on them for steam production. W. L. FRENCH.

Testing the New York Engineer's Brake Valve, Model 1902.

Owing to the modifications made in the construction of the New York Engineer's Brake Valve, the method of testing the 1902 model is somewhat different from that recommended for the older VaughnMcKee brake valve, the change in method of testing, of course, being due to the modifications introduced.

When making a thorough test to ascertain the condition of the different valves in the 1902 model, the first valve to receive attention should be the main slide valve 114 A, which is shown, together with the other modified parts of the 1902 model, in Figs. 1, 2, 3, 4 and 5, and to which the reader is referred.

The main slide valve 114 A controls the communication between the main reservoir and the train pipe, and also between the train pipe and the atmosphere. The communication between the main reservoir and the train pipe should be perfectly controlled, and also the communication. between the train pipe and the atmosphere.

Therefore, to test for leakage past valve 114 A, place the handle 123 of the valve in lap position, and close the brake valve cut-out cock, in the train pipe, below it.

Having done this, start the pump, and charge the main reservoir and chamber, B, Fig. 1, with full main reservoir pressure. While the pump is accumulating the pressure in chamber B, observe the black hand (train pipe) on the air gauge, and note if there is any perceptible increase in train pipe pressure or a blow at exhaust passage C. If there is, the main slide valve is leaking; and the rapidity

with which pressure increases in chamber A or the train pipe indicates the degree of leakage past the valve.

The above method for testing the main slide valve applies, as will be readily understood, when the brake system is without pressure, and the pump is started to supply pressure, after the handle of the brake valve is placed on lap.

Should the brake system be already charged, and it be desired to test the main slide valve, the following is the method that should be used:

Close the brake valve cut-out cock as before, and place the handle of the brake valve in the emergency position. This will empty the train pipe, and cause the

gine, so that any slight leakage into it quickly increases the pressure therein, and makes it easily perceptible on the air gauge.

The next thing to ascertain is, whether the brake valve will automatically lap the service port F or not in a service application. If it will not, the failure to do so may be due to one, or several combined, of the following causes: Leakage from the supplementary reservoir and its connections, both at the reservoir and at the brake valve connection to passage H; leakage through back cap gasket 167; past packing leather 107 and packing ring 3; past ball check valve 184; and possibly at either or both of the places where port

black hand on the air gauge to fall to zero, or, as some say, to the peg. Then move the handle back to lap position. This will permit the pressure behind piston 104 A, in chamber D and the supplementary reservoir, to escape to the atmosphere, thus removing the possibility of leakage past this piston into train pipe chamber A, which might be mistaken for main reservoir leakage past main slide valve 114 A if piston 104 A leaked. Any pressure that is now indicated by the black hand on the air gauge is caused by the main reservoir air leaking past the main slide valve into chamber A.

The reason for closing the brake valve cut-out cock when testing the main slide valve is to reduce the volume of the train pipe, making it very small compared to that of the whole train pipe on the en

O passes from the valve body 101 A into the valve cover 115 A, as indicated in Figs. 1, 2 and 5.

To test for any leakage that may be present at the supplementary reservoir connections, both at the reservoir and at the brake valve, at the back cap gasket 167, or from port O, along the joint which the valve cover makes with the valve body, all that is necessary to do is, while all parts of the brake valve are charged with air, to coat the unions, joints, etc., with soapsuds or kerosene, when any leakage will be quickly indicated by the air bubbles, which will arise.

To test for leakage past ball check valve 184, packing ring 3 and packing leather 107 combined or singly, close the brake valve cut-out cock (to reduce train pipe volume), and move the handle of the

voir. Pulling the handle of the brake valve back to lap position, after air ceases to flow from passage C, and hearing no air escape at exhaust passage C, is a further proof of leakage past these parts.

To be able to tell whether the leak is past the ball check 184 or the packing leather 107 and packing ring 3, would require long experience in testing these parts; but then it would be of no practical value to us as, if any one of these parts is leaking, the whole piston must be

Fig. 3. Cross Section-New York Engineer's Brake Valve, Model 1902

If valve 180 leaks, move the handle to service position and back again once or twice and the leak will cease unless something about the valve is loose and out of place.

Should the small graduating, or cut-off, valve 110 leak it will permit train pipe air to escape to the atmosphere through exhaust passage C, in service applications, after it has moved far enough to cover port F. To test this valve have all brakes released, and the train pipe fully charged.

Fig. 4. Face of Main Slide Valve-New York Engineer's Brake Valve, Model 1902

110 entirely covers port F, so that all air that leaks past cut-off valve 110 enters port F, and escapes to the atmosphere through port G and exhaust passage C.

After a little experience in testing the 1902 model brake valve for leaks according to the above instructions, it will be found quite an easy matter to locate a defective valve or, if a combination of leaks exists at the same time, to tell which valves are at fault.

The excess pressure valve 97 may leak sometimes, and if it does the effect it will have on the operation of the pump will depend somewhat on the way the pump governor is piped to the brake valve.

If

enough to keep the train pipe pressure below seventy pounds or whatever pressure the governor is adjusted for, and then note if the pump starts to work and increases the main reservoir pressure to near 90 pounds, or to 20 pounds more than the train pipe pressure. If the pump governor is piped to chamber A, place the handle of the brake valve on lap position, and note whether the pump starts to work promptly at its usual rate of speed until full main reservoir pressure is obtained. If it does, a leaky excess pressure valve is indicated.

With the pump governor piped to chamber E, of the brake valve, and you are unable to obtain excess pressure, with the handle in running, or in lap, position, it is likely that the excess pressure valve is leaking sufficiently to keep chamber E charged to the limit of pressure for which the governor is adjusted, causing it to operate continuously, and so hold the pump throttled down.

And the same is likely true if the pump governor is piped to chamber A, and you are able to obtain full main reservoir pressure with the handle in lap position, but can not obtain any excess pressure with it in running position.

When testing the excess pressure valve care should be taken to know that the pump governor is working properly, as if there should be leakage past the dia

the governor is piped to chamber E, just forward of the excess pressure valve 97, it will prevent the pump from accumulating excess pressure in the main reservoir, at all times; but if piped to chamber A it will prevent the accumulation of excess only while the handle is in release, and in running position. To determine whether it is leakage past this valve that is holding the pump down in speed or not, place the handle in running position, open one of the angle-cocks on the engine, just

phragm air valve 13 it will produce an effect similar to a leaky excess pressure valve, and you might be deceived in thinking the valve at fault.

The condition of the brake valve cutout cock with regard to leakage may be ascertained by closing it, and opening the angle-cock at the rear of the tender, letting all air escape from the train pipe, below the cut-out cock; and by releasing all air from the auxiliaries through the release valves. Then immerse the end of

After a hard, six-mile climb, we pulled into Summit siding, to meet "everything on the road," as White Line George said. He was braking ahead, and after letting us in, stayed and set up the switch, so as to catch the cabcose and eat his lunch. Dooley Dunn came down out of the cupola, and the two began dropping eggs into a bucket of hot water on the stove. I was dead-heading over the road and picking up a few air brake points, as I usually do when I ride with Tim Grogan. He had gone down to the telegraph office, and I caught the opportunity to get the boys started.

"Say, George," I inquired, "how did Timothy get along on passenger, last month?"

"Oh, all right, I reckon; they can't throw him none now. He done got initiated last summer on them Lakeside excursion trains-you all heard about Grogan bringin' that nigger Sunday-school train back to Corning without his air a workin', an' me an' Dooley, there, a tryin' to do the armstrong stunt? Well, it were this way: They give us one of them suburban injines, with a cowsnatcher on both ends, an' old Peggy Grimes. Peggy's first show at the main line in eight year, an' he's a givin' the coons a hay ride fer their money 'round them bone breakin' curves this side a Sundown, a gettin' their religion an' natural cussedness sorta mixed up, but when old Peggy comes a cayoodlin so gaily out onto the straight track, what you all a guessin' he sees? It were a house on the track."

Dooley let a couple of eggs fall on the floor, and both brakemen lay back yelling with laughter.

"Fireman says Peggy looks straight at that house, probably thinkin' he's got 'em agin, till fireboy yells, an' then Peggy gives her the quick-business an' stops with the pilot nosed right under this yere

navigator's kitchen where some females is a gettin' dinner-no, it weren't the Bender family; 'twere some corn-fed Hoosiers, a tryin' to move their house over the crossin', an' hadn't sense enough to flagdidn't figger on no trains what weren't scheduled. An' it took all the diplomacy of the crew to keep them skeered niggers from makin' a mighty rough housewhich the same were not long remainin' on the right-of-way.

"This yere little diversion spiles the day for the niggers, an' for us, too. Peggy don't see nothin' wrong with the injine, an' when we get to the Lake we cut her off an' run 'round the train, an' couple to it from the pilot. He had shut off his pump an' didn't start it again till nigh on to leavin' time, an' when he did we found the brake train pipe broke, back of the pilot, atween the cut-out cock behind the steam chest, an' the pilot hose; that's the reason it weren't noticed afore -hadn't been no pressure there, an' it broke when we hit that shack.

"Well, Grogan don't know what t'ell, but he's equal to any old occasion, an' says 'Well, well, Peggy, get a fix on that; ain't got much time,' but Peggy's some dubious, an' finally says it's all off-have to brake by hand; an' he shets the cut-out cock.

"That's leavin' him all right with his driver and tender brake; I see Grogan now gettin' red an' sorta puffin' out, an' I says 'Pap, don't you all know that every passenger crew on the road is supposed to carry a pair of combination hose, with brake couplin' on one end an' a signal couplin' on the other? If we had a pair we'd be all right-which we ain't.'

"Now I don't know; I'm makin' a bluff to queer Grogan; it's the first time he knows they was such things; but he makes his face sharp as a dime's worth of cheese an' says 'Mister Grimes, get your commodation hose an' you won't have any trouble in fixin' that, a-tall. The brakes are in proper condition on my keers an' I expect you to connect with 'em soon as possible.'

"That hits Peggy below the belt, but he was educated in the same alley with Grogan, an' he hollers to the fireman'Hay, son, look in the box an' get that consolidation hose, an' be quick.'

"Well, the fireboy ain't got no understudy, so he goes a fishin' an' drags out a hose as he ain't seen none like it afore, with two couplin's, one painted black an' the other red, an' he hops down an' delivers the goods afore Grogan has time to get away.