Early American Laconialives. —The earliest Baldti. in engine was the "Old Ironsides," built in 1832 (pi 99, Jig. 1), a four-cylinder engine of English type, and weighing in miming order a little over five tons. The cylinders were 9;4 by 18 inches, and were attached horizontally to the sides of the smoke-box, which was D-shaped and recessed to allow the centre lines of the cylinders to be in line with the centre of the crank. The valve-motion for each cylinder was a single loose eccentric placed on the axle between the crank and the hub of the wheel. On the inside of the eccentric was a half-circular slot, running halfway around; the stop, which was fastened to the axle at the arm of the crank, terminated in a pin which projected into the slot. The engine was reversed by changing the position of the eccentric on the axle by a lever worked from the foot board. Subsequently, this form of valve-motion was changed to a circular fixed eccentric, with rock-shafts having arms above and below, and the eccentric straps had each a forked rod, with a hook or an upper and lower latch or pin, at their ends to engage with the upper or the lower arm of the rock-shaft. The cylinders exhausted against each other at first for the reason that the exhaust-pipes were not properly arranged, a defect that was afterward remedied by turning each exhaust-pipe upward into the chimney, substantially as is now done.
Boilers of early American locomotives were similar to the boiler of Stephenson's " Planet " (fig. 4)—that is, they had a semi-cylindrical top, flush, or nearly so, with the top of the barrel, and also had a square, or nearly square, horizontal section of the fire-box below the barrel. About 1837, Bury of England made the top of the furnace hemispherical, and the horizontal section below the waist was D-shaped, with the flat part in front. This form of boiler was very soon adopted in America 3). Coal (first used by the Baltimore and Ohio Railroad) required larger fire boxes than wood, and the hemispherical top was succeeded by a semi cylindrical, type, the crown-sheets being stayed by crown-bars running eithLr lcilAtilwise or crosswise. These semi-cylindrical tops, which were at first flush with the tops of the barrels, were followed by the " wagon top" (p1. 6, 7), the semi-cylindrical furnace-tops cooling higher than the top of the barrel, giving more steam-room and allowing more tubes to be used, and also affording better facilities for construction, inspection, and repairs. Baldwin adhered to the dome until 185o. For the use of anthracite, which required longer boilers than bitu minous coal, there was produced the Milholland type (Jigs. I, 2), which had a fire-box top sloping down from the barrel, and whose crown-sheet was screw-stayed. This was first introduced on the Philadelphia and Reading road. The Belpairc fire-box (p1. 75,figs. 3, 4), having a flat top as high as the cylindrical part of the barrel, is used upon some American roads. The smoke-boxes were not "extended" until about 1859, and in that year also there was added the deflector, which had an adjustable piece at its lower edge. The telescopic or adjustable "petticoat pipe"
was introduced about 1862.
The is one of the most important minor accessories of the locomotive, by reason of its great influence in preventing destruction of property along the line. About the first device was a wire " bonnet " placed over the whole stack; this was followed by a conical " defleetor " over the smoke-pipe proper. There have been so many various combina tions of cones and wire netting that it would be impossible to mention them all here. One of the few departures from these, however, consists in the additibn of a water-tank below the ordinary diagonal deflector, against which the sparks are driven and thrown down into the water, while the gases of combustion make a turn around the edge of the plate and go up the stack. Another type had a number of spirally-arranged screw-blades through which the current of gases had to pass, and the sparks, being thrown against the sides of these blades, were stopped in their upward course and made to fall back into the " front end." The extinguished sparks found in the tank at the end of a run show what has been prevented from going up the stack and out into the air. The fact that the material which is collected from the various spark-arresters is fairly combustible shows that there would be economy in their use. Figure 2 (fii. ioo) shows a spark-arrester for bituminous coal, and Figure one for wood.
Luttgens proposes an arrangement of damper by which the effect of the exhaust might be diminished by admitting air to the base of the stack when desired.
Heaters for locomotives have been repeatedly tried, but have not met with success or favor. One of the earliest, which was car ried under the front end of the boiler, was about the same ill general design as the ordinary horizontal multitnbular heater for stationary boilers.
iron is the material of which nearly all locomotive grates are made ill the United States, and this has been the case almost since the introduction of railroading here. Cleaning-grates are necessary for grades of bituminous coal, which have a tendency to " clink." Some of these grates have projecting side-lugs cast on each bar, the lugs of one bar pro jecting between those of the other, the cleaning being done by a slight upward-and-downward movement of each bar. In the finger-bar type the bars have a rocking motion upon axes lying across the fire-box, and the fingers are made to project into the fire 74, figs. 3, 4). There are also employed wide flat bars rocking upon journals at the sides, each whole bar acting as a wide finger. The water-tube grate, which consists of length wise tubes through thimbles from which they can be removed (figs. i, 2), is very common for anthracite. A solid bar takes the place of every fourth tube. Water-grates were used in the Milholland boiler.