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pressure head of the duplex pump-governor, and the reasons for this connection will appear in the explanation of the SF-4 pump-governor.
The reducing-valve pipe leading from the reducing valve to the independent brake-valve, has a branchpipe connection with the train air-signal system, when used. In this branch pipe is placed a combined strainer, check-valve, and choke-fitting: the check-valve to prevent return flow of the signal-line pressure when an application by the independent brake-valve is made, and which would cause the air-signal whistle to sound; the strainer to prevent dirt from lodging in the checkvalve; and the choke-fitting to so reduce the rapidity of air supply to the signal line that the opening of the car discharge-valve can reduce the pressure in the line and cause the air whistle to blow.
The distributing valve has five pipe connections (see Figs. 2 A and 2 B), made through the end of the doublechamber reservoir, three on the left and two on the right; only one of them (the middle one on the left) enters either of the chambers of the reservoir, and they are all directly related to the valve section, being ported through the large, round gasket between the faces of the reservoir and valve sections of the distributing valve. The pipe connections being made to the reservoir section, it enables the removal of the valve section for exchange or repair without having to disconnect any pipe
Fig. 2 A.—No. 6 Distributing Valve, Left Side, showing the Pipe
Connections. MR, to main reservoir; 2, application-cylinder
pipe; 4, distributing-valve release-pipe. Fig. 2 B.—No. 6 Distributing Valve, Right Side. CYLS, brake
cylinder pipe (branching to all brake cylinders of engine and tender); BP, distributing-valve branch of the brake pipe.
Brake-Cylinder Cut-Out Cocks unions. Of the three pipes on the left, the upper is the supply from the main reservoir; the intermediate is the application-cylinder pipe, leading to the independent and the automatic brake-valves; and the lower is the distributing-valve release pipe, leading through the independent brake-valve, when the handle is in running position, to the automatic brake-valve and through it, also, when in running position, to the atmosphere, as shown in Fig. 1 by the continuity of color. Of the two on the right, the lower is the brake-pipe branch connection, and the upper is the brake cylinder pipe, branching to all brake cylinders on the engine and tender. In this pipe are placed cocks for cutting out, individually, the brake cylinders when necessary, one each for the tender and engine truck-brake cylinders, and one cock to cut out both driver-brake cylinders at once, as it is inadvisable to operate the driver brake on one side of the engine only; and in the engine truck and tender brake-cylinder cut-out cocks are placed choke-fittings to prevent serious loss of main-reservoir air and the release of the other locomotive brakes during a stop, in case of burst brake-cylinder hose. Each one of the pieces of the E-T equipment referred to in this description of the piping arrangement will be explained in detail, and with accompanying illustrations, further along. The TWO DUPLEX AIR-GAUGES (see Figs. 3 A and
3 B) are connected as follows: Gauge No. 1; red hand to main-reservoir pipe under the automatic brakevalve; black hand to gauge-pipe tee of the automatic brake-valve; this gauge is piped correspondingly the same as the original duplex gauge of the automaticbrake equipment with which we have been familiar
Fig. 3 A.-Large Duplex Gauge. (Corresponding to the one duplex
gauge used in former equipments.) Fig. 3 B.-Small Duplex Gauge. (Corresponding to the brake cyl
inder gauge used in former equipments of the E-T brake, but with a second pointer added to show brake-pipe pressure direct.)
for years, but the inscription on the dial is more strictly accurate, for instead of the legend “black hand train line” —meaning brake-pipe pressure—it now says BLACK HAND EQUALIZING RESERVOIR, which pressure it records and always has recorded. Gauge No. 2; red hand to
The Two Duplex Air-Gauges the brake-cylinder pipe; black hand to the brake pipe below the double-heading cock; thus, for the first time, in connection with the equalizing-discharge automatic brake-valve a gauge is supplied that directly indicates the pressure in the brake pipe at all times, regardless of the position of the brake-valve handle, and is of special benefit on the secondary engines in double-heading whose double-heading cocks are closed.
The amount of reduction to be made during an automatic application, however, is indicated by the black hand of gauge No. I, as the E-T equipment does not require any change in the governing of automaticbrake applications at either service or emergency reductions.
The automatic brake-valve connections, other than those already mentioned, are the brake pipe, the pipe to the equalizing reservoir (sometimes referred to as the chamber D reservoir), and the lower connection to the excess-pressure head of the pump-governor.
Before beginning on a detailed description of the operation, and the construction of the operating parts, of the No. 6 E-T equipment, it is desired that it shall be positively understood that the underlying principles governing its action are just the same as those of all previous equipments of the automatic air-brake. Instead of a triple valve and auxiliary reservoir for each of the engine and tender equipments the parts men