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.

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 puting 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 far 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 mechani

cal 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.

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.

Some seventy-five of these stokers have been applied to locomotives to date, and are firing the locomotives successfully.

This is a drawing showing the general arrangement of the Hanna overfeed scatter type locomotive stoker. The peculiar

characteristic of this stoker is the use of a combination of movable mechanical directing means and continuously operating steam jets for

distributing the coal over the grate area. It also has means for crushing the coal preparatory to forwarding it to the elevating and firing means.

The driving motor is a twin-cylinder, double-acting steam engine placed on the locomotive tender, usually in one of the forward ends of the water space. The operating routine is to have the coal passed to the crusher through the opening in the deck of tender, and after being crushed the coal is forwarded by a cast-steel helicoid screw to a receptacle at the base of the elevating means, which is another cast-steel screw placed in the vertical casing just at the left of the ordinary fire door of a locomotive. At the top of the elevating means is a large elbow, or goose-neck, through which the coal is forced by the pressure of the vertical elevating screw and finally falls by gravity over the directing vanes, or wings, to the firing plate placed inside of the regular firing door of the locomotive.

of the Hanna stoker.

This photographic view shows the firing plate, above which will be noted the main nozzles of the firing jets placed in fan-shaped arrangement, and above these jets will be seen the ridge plate and movable mechanical means or directing wings, which serve to assist the jets in distributing the coal over the grate area. Just below the main jets is a long slot in the casting at the level of the firing plate, and this can just be seen in the view.

This delivery of the coal to one side of the firebox for a short time and the similar delivery in turn to the other side would make it proper to classify this stoker with those of the intermittent firing. type, as a charge or "fire" is, in a partial sense at least, delivered to the different sides of the firebox and allowed to burn until the cycle of mechanical movement brings another delivery of fuel. The jets are constantly in action, the mechanical directing means are also continually in motion, but the delivery of the fuel is intermittent an arrangement just opposite from that of most stokers of the overfeed type.

The fan-shaped arrangement of main jets serves also as a fork, or set of fingers, to partially separate the coarser lumps of coal from the fine slack, which latter drops to the firing plate and is forced to the grate area by the low-pressure steam emitted from the long slot just mentioned; the larger particles are more violently forced by the steam jets to other parts of the grate area.

Approximately seventy-five of these stokers have been applied to locomotives to date, about fifty of which of the latest design are in daily service and firing locomotives successfully. About twenty of the earlier forms of this stoker, with which the fireman was required to shovel the coal into the hopper below the elevating means of the stoker proper, were applied to locomotives, but found to be either not practical or of sufficient advantage to warrant their continued use. Those at present in service, however, are giving good satisfaction.

This is a drawing showing the general arrangement of the Crawford mechanical underfeed stoker as in use on a large number of Consolidation and Pacific type locomotives on the Pennsylvania Lines West.

This stoker was designed and developed by Mr. D. F. Crawford, General Superintendent Motive Power, Pennsylvania Lines West, and, as it was one of the first stokers to be applied to locomotives other than in an experimental way, it is of special interest in connection with the subject of the evening.

As explained earlier in this paper, the different stokers which have been developed have each individual characteristics as to mechanical design and method of handling the fire. This stoker is the foremost representative of the underfeed principle of firing; it has been in continual operation for the past four or five years, and well illustrates what can be done in the matter of successfully firing locomotives in that way.

The Crawford stoker is designed on the theory that the use, more or less completely, of the coking or gas producer process, during the progress of combustion, contributes toward economy and reduces the amount of black smoke usually made by a locomotive when working at or near its maximum output, and to secure this coking of the coal the fuel must be supplied to the fire from the bottom upwardly, hence the term underfeed stoker.