Locomotive AT&SF 940

Transcribed from Railway Age of May 30, 1902

Page 2

VALVES AND CYLINDERS

The main steam valves are of the piston type, 13 inches diameter, both valves being connected to a continuos valve rod actuated by an indirect movement imparted by the usual link motion and extension bar. The valves are hollow throughout their centers. The valve governing the steam admission to the high-pressure cylinder has four heads so arranged in relation to the ports that internal admission is obtained. the valve controlling the admission to the low-pressure cyllinder is of the ordinary piston form, with outside admission, the ports being arranged in the usual manner employed on simple cylinders. The cylinder and valve diagram shows clearly the course of the steam through the valves and cylinders, and a further explanation on this point deemed unnecessary.

TRANSVERSE SECTION AND PLAN OF CYLINDERS.

The high pressure steam is brought to the cylinder saddle by the usual steam pipes, the passageway in the saddle however, terminating at the forward end at a point on a line opposite the center of the high-pressure cylinder. An elbow conveys the steam from the saddle to the high-pressure cylinder, where it enters at the point shown in the cross-section plan of the cylinders. The ordinary form of ball joint is used to make this connection. In the tandem arrangement of cylinders, as generally used in locomotives practiec, it is necessary to remove the front cylinder, in many instances, in order that proper repairs may be made. In the present design a very novel and practical arrangement of details at this connection has been employed to facilitate the removal of the forward cylinder, which also allows for the necessary movement due to expansion. The front head of the low-pressure cylinder is held in place by the high-pressure cylinder by studs passing through the flanges cast on the rear of the high -pressure cylinders. An auxilary casting is bolted to this head, which to all intents and pruposes forms the rear cylinder head of the high -pressure cylinder. The construction of these two castings is such that a pocket is formed between the two cylinders, which permits of using a special packing designed to fit in this space. The whole is held securely together by the studs before mentioned.

STEAM CHEST VALVES

The manner of connecting the steam chest or recievber at this point is accomplished by cutting the bushing into two seperate parts. The bushing of the high -pressure cylinder which is helld in place in the usual way, projects from the inner face a sufficent distance to enter the steam chest on the low-pressure cylinder. A stuffing box and gland are used on this end of the bushing, packed with ordinary hemp and held in place by the combination gland studs, as can be plainly seennn on the drawing. This allows for expansion at this point and also provides a very convenient way of making this connection. The exhaust on the low-pressure cylinder is connected to the the cylinder saddles in the same manner, the stuffing box being provided for in the saddle. Thus, these connections are readily detachable , and to further facilitate the removal of this cylinder stationaary cranes are provided on each side of the smokebox. It is thereby possible to remove the high-pressure cylinder at any time necessity may require. This would seem to be a particuularly useful appliance on this design of engine.

END ELEVATIONS OF HIGH AND LOW PRESSURE CYLINDERS

One relief valve is screwed into the front steam chest head is used for the low-presure cylinder. Relief and saftey vavles which lead into the steam passageway to the high-pressure cylinder are provided for that cylinder. The by-pass vavle used on this engine is a form of plug vavle which is shown in detail and is secured to the high-pressure cylinder on its upper face, the location showing on the plan of the cylinders. This valve is operated from the cab in tue usualy Manner.

PASSAGE OF STEAM THROUGH CYLINDERS.

To previous page, to next page