The connections through the automatic brake-valve, as established in the different positions of the rotaryvalve handle, will be made plainer in the views subsequently to be given that will represent the rotary valve as transparent, and in the course of the description the reader will be referred back to this plate occasionally. The highest plane of the middle piece of the brakevalve body, 3, forms the seat of the rotary valve, and this casting is catalogued in whole as ROTARY-VALVE SEAT. The lower portion of the brake-valve proper -piece 2-is called BOTTOM CASE, and contains the EQUALIZING-DISCHARGE PISTON AND VALVE, 15. The three large gaskets making the joints between the three sections of the brake-valve proper, and the pipe bracket, are named as follows: 17, UPPER GASKET; 18, MIDDLE GASKET; and 19, LOWER GASKET. The large cavity in the center of the rotary-valve seat, marked EX, opens to the atmosphere through the large exhaust port leading out through the back side of the brake-valve body (this port is shown in dotted lines in the upper, plan, view).

To lubricate the rotary valve, remove OIL PLUG 29 before main-reservoir pressure is pumped up, and pour a little high-grade machine oil in the hole; it will fill the small recess around the inside of the top case at the converging edges of the rotary valve and seat. With this brake-valve, it is also possible to keep the

Details of H-6 Brake-Valve

leather KEY-WASHER, 8, soft and well lubricated, by removing handle lock-nut 14 and dropping some machine oil into the hole that is drilled down through the center of the ROTARY-VALVE KEY, 7; the oil fills the transverse port that is drilled clear through the handle. key, and when main-reservoir pressure is off the rotary valve it seeps down between the washer and bearing surfaces of the rotary-valve key and top case, lubricating a point that has usually been neglected, and that when dry and gummy offers a greater resistance to the turning movement, sometimes, than a dirty rotary valve does.

Rotary-valve spring 30 holds the rotary valve and the key apart from each other, and to their seats, in the absence of main-reservoir pressure in the brake-valve, and this has the good effect of keeping dirt and scale from being blown on the seats when the pump is started. The HANDLE, 9, contains LATCH, II, which fits into notches in the quadrant of the top case, so located as to indicate the different positions of the brake-valve handle; HANDLE-LATCH SPRING IO forces the latch against the quadrant with sufficient pressure to indicate each position.

In referring to Fig. 22, it will be noticed that the removal of the four long bolts that go through the brakevalve as a whole will not permit the separation of the parts of the brake-valve proper. The plan view of the rotary-valve seat in Fig. 23 shows the location of these

bolt-ends and nuts, 27, which must be taken off to remove the brake-valve proper from the pipe bracket; but to take apart the body sections of the brake-valve, for cleaning, oiling, etc., the cap screws, 28, must be removed, and these are shown as the two, plain, hexagon screw-heads, exactly opposite each other in the flange of the top case.

THE EQUALIZING-DISCHARGE VALVE.-If the engineman was to make all reductions of brake-pipe pressure directly through the rotary valve to the atmosphere, as he does in the emergency position, he would have to exercise an almost impossible skill to discharge the pressure rapidly enough with a long train, to get the pistons beyond the leakage grooves in the brake cylinders, and yet not fast enough to cause the quick-action triple valves to respond with their emergency action. The EQUALIZING-DISCHARGE VALVE, that has been an integral part of all Westinghouse brake-valves. manufactured since 1890, automatically discharges the brake-pipe pressure during service applications at a rate of flow that is partly predetermined in the construction of the brake-valve, and partly governed by the volume of brake-pipe air that is being reduced; the number of brake-pipe pressure-pounds of the reduction is determined by the length of time the brake-valve handle is permitted to remain in the service-application position-with the older brake-valves, about 5 pounds per second.

Equalizing-Discharge Feature

In Fig. 23 the lower view of the brake-valve shows the equalizing-discharge mechanism very plainly; there is but one operating piece, the EQUALIZING PISTON, 15, with its PACKING RING, 16, the lower end of the piston stem forming the VALVE. Under the piston is brakepipe pressure, and under the valve is atmospheric air in the "exhaust fitting." Above the piston is the air of CHAMBER D, which in the running position of the brake-valve is connected to brake-pipe pressure, and the pressures thus being equal on the top and bottom sides of the piston (at this time), it remains in the position shown with the valve seated.

(Although the per-square-inch pressures are equal on both surfaces of the piston, there is more pressure on the top than on the under side by just the area of the valve at the end of the stem that is exposed to the atmosphere; this slight difference in forces insures the proper seating of the valve.)

There must be substance to work on, always, and chamber D must have volume-something near a cubic foot of it—as well as pressure; but, to make it of that size the brake-valve would take up too much room in the cab; so, chamber D is made as small as possiblecontaining room merely for the necessary "lift" of the piston and another chamber is provided elsewhere (usually outside the cab, under the running board), called the equalizing reservoir, in size 10-inch by 141

inch (formerly made 10-inch by 12-inch), which is in permanent connection with chamber D by a 3-inch pipe leading from the lower union of the GAUGE AND EQUALIZING-RESERVOIR TEE, 21; and to the upper union of this tee, or fitting, 21, is connected the 1-inch pipe to the large duplex gauge, the pressure of chamber D and equalizing reservoir registering by the black hand.

The legend "black hand, equalizing reservoir,” is on the face of this gauge in the No. 6 equipment; in all previous locomotive-brake equipments the legend read “black hand, train line” (brake pipe), because, in the running position of the brake-valve the equalizingreservoir and brake-pipe pressures are always the same, and previous to the No. 6 equipment there was no other means of gauging the brake-pipe pressure.

Very few of the pipe connections and ports in the brake-valve are to be seen in Fig. 23. The feed-valve pipe connects to the pipe bracket as shown in the preceding piping diagrams, and its 70-pounds pressure (brown) comes up through port d in the rotary-valve seat (upper view, Fig. 23), flowing into cavity f in the face of the rotary valve, which, as is seen in the lower view, is also in register with brake-pipe port b in the seat; the brake-pipe connection to the pipe bracket is nearly under port c in the rotary-valve seat with which it is directly connected: note this in the upper view,