20 Hanna stokers-overfeed type.

365 Crawford stokers-underfeed type.
600 Street stokers-overfeed type.

The 200 stokers applied at one time or another and later removed were not of these makes, with a few minor exceptions.

Before proceeding further with the general aspects of the subject, I should like to have you familiar with the details of these machines and some of the locomotives on which they are in use.

This is a plan view of the Barnum underfeed stoker. This was one of the stokers applied to locomotives experimentally and later on removed. One of the other slides will show the locomotive to which this stoker was applied. This stoker is of the underfeed type, having two or more stoking troughs placed longitudinally of the firebox. This drawing shows seven of the stoking troughs, but only three or four were used in the actual installations. The troughs were supplied with cast-steel helicoid screws, the flights of which were reduced in size at different points in their length, each diameter being about two feet long, and at the offset, where the reduction in flight took place, deflectors or partial partitions were provided, with an aperture equal only to the next reduced diameter of the flight of the screw. The effect of the use of these deflectors was to cause the coal to be lifted up out of the stoking troughs and forced over on to the grate areas at each side, and, of course, part of the coal was carried on through the reduced openings in the partitions until the next deflector was reached, where more coal was deducted from the quantity being forced along in troughs, and this continued until part of the coal had been carried to the extreme forward end of the firebox and forced up out of the trough by the bottom being slightly inclined upward. These stokers were operated by the use of two double-acting steam engines, one placed on each side of the locomotive at the end of the cross shaft. The screws were driven with worm drive, the worms being on the cross shaft and the worm wheels being at the back end of the cast-steel screws. Separate crushers of ample capacity were placed on the locomotive tender to prepare the coal.

Seven or eight of these stokers were applied and at least four or five of them saw considerable service with quite a number of

different kinds of fuel and on locomotives of different types, at least one each being applied to a Switch, a Prairie, a Mikado, and a Decapod type of locomotive.

The results in service were quite satisfactory when the conditions existed which were favorable to the use of this kind of a stoking machine, and many successful trips were made with these stokers, taking the average of which it could probably be said that

75 per cent. of the coal burned on the trips made was fired by the stoker. The difficulty with this particular machine was probably more from mechanical shortcomings than from any inherent defects in the general scheme, although the results were not equally satisfactory with all kinds of coal used. It will be readily appreciated that, with the method used in firing with this stoker, there would not be the flexibility of control of the fire that will be noted with other stokers which will be shown and described.

This is a general plan view drawing showing the forward part of the conveying mechanism of the Gee overfeed scatter type of stoker and also the movable directing wings which are placed above the firing plate at the bottom part of the ordinary fire door. One of these stokers has been applied to a consolidation locomotive on the Pennsylvania Railroad, and is in operation in regular service to-day, firing the locomotive successfully. A crushing mechanism is placed at the back part of the conveyor of this

stoker, which also serves as a measuring or feeding device to start the coal into the forwarding means of the conveyor.

This view also shows a cross-section of the forwarding vanes of the conveyor. These are not made all in one piece, but are practically fingers which drop back of the coal in the backward movement of the reciprocating conveyor and serve to push part, or all, of the coal in their vicinity forward, to be engaged by the next succeeding set of fingers in the following action of the conveyor. The reciprocating action of this type of conveyor accomplishes the purpose not only of forwarding the coal but of partially measuring it and serving it to the firing plate in separate charges, and the steam blasts are operated in timed relation to the forwarding of these separate charges of fuel, and serve as plungers to inject the coal into the firebox in very much the same manner as it would be fired with a scoop.

The direction of these separate charges of fuel to the different parts of the firebox is accomplished by the movement of the wings, in relation to which the jets are also controlled, so that when the wings are pointed toward the left-hand side of the firebox the jet on that side is shut off and the right-hand jet serves to force the charge of fuel in conjunction with the wings over to the left-hand side of the firebox, and so on.

This is a photograph showing the general view of this stoker and with the deck of the tender and locomotive removed, so that the conveyor can be seen almost through its length. The crushing mechanism is just back of that part of the conveyor shown in the lower margin of the photograph. The position of the stoking mechanism itself, just below the fire door, can be readily observed in this view.

This stoker is operated by means of a steam cylinder placed at the side of the locomotive and attached to the frame just below the fireman's seat-box. The connection between this operating steam cylinder and stoker is by means of a cross shaft with the necessary arms and connections to give the conveyor and elevating mechanism the reciprocating action required by this particular design of forwarding means.

The individual characteristics of this particular stoker are the firing of the coal over the fuel bed in separate charges, representing very nearly the general scheme of hand firing and the necessary intermittent action needed to permit each charge of fuel to be consumed before another is placed in the same location in the firebox.

This stoker is firing a locomotive successfully, but has not been in service long enough to warrant any conclusions as to its commercial possibilities, only one of them having been put into service to date.

This is a general view of the Standard stoker showing arrangement of conveyor, jets, and grates. This stoker is also of the overfeed scatter type, but it has the peculiarity of firing the locomotive by putting the coal into the firebox by conveying it to

a point just below the back section of the grate area and elevating it by a vertical screw placed in a firing pot in the middle of the back part of the firebox. The distribution of the coal over the grate area is by steam jets, the nozzles for which are placed so as to come in the midst of the body of coal just as it reaches the top of the vertical screw, and the distribution is secured by having the jets pointed toward different parts of the grate area. There are no movable or stationary mechanical directing means to assist the steam jets in distributing the coal as with other stokers.

This stoker is one of those designed to supply fuel at a continuous rate over the entire grate area as compared with the intermittent action of the Gee stoker, which fires the coal in separate charges, as just described.

The Standard stoker also has arrangements for crushing or preparing the coal, this being accomplished by the use of a crushing zone at the forward end of the heavy cast-steel helicoid screw shown in the left-hand section of this general view. The necessary flexibility for the movement between locomotive and tender is secured by the ball joint actions, also plainly shown in the view. The power motor which operates this stoker is a small, highspeed steam turbine on the left-hand side of the locomotive, and connection is made to the stoker through a train of gears with suitable reversing mechanism required for the clearing of the stoker from foreign matter or clogs of any description.

Suitable arrangements are provided for adjusting the jets to different degrees of force and also to shut one or more of them off when it is desired to stop the forcing of coal to any given part of the firebox. The general action of the jets is intermittent, being controlled by an operating valve moved mechanically by the arm and rod connection shown.

It might occur to you that the action of the jets being intermittent would result in firing separate charges of fuel to the grate area. This, however, is not actually the case, as the action of the jets is graduated so that the building up of the blast to maximum and decreasing in force to the minimum serves the purpose of waving the coal over the grate area by the use of the increasing and diminishing forces of the jets, and the valve controlling the jets begins to open almost immediately after each jet action, so