passes into the heating pipes of the car, through the cut-out valve, and back to the regulator which it re-enters at the port marked on the cut "entrance to outlet chamber," flowing down to the "outlet chamber" where it heats and expands the thermostatic diaphragm E and causes the valve S to be forced toward a closed position-closing it, in fact, when live steam at 212 degrees has blown on the diaphragm for a moment.

But, as soon as the valve S closes, the passage of steam to the diaphragm ceases, and necessarily the temperature of 212 degrees that surrounded the diaphragm when live steam was blowing around it immediately starts to fall

and the diaphragm begins to contract; by the time the temperature around the diaphragm has dropped to about 200 degrees the liquid within it has accordingly lost part of its expansive force, due to the drop in temperature, the diaphragm has contracted a little and this permits valve S to open slightly, again admitting steam to the heating pipes.

Steam will now continue to pass into and through the heating pipes in sufficient quantity to provide a temperature around the diaphragm, at the outlet, slightly above 200 degrees; if the temperature at the outlet drops below 200 degrees, the diaphragm will contract and open up the valve S, which will instantly let in steam from the train pipe until the outlet gets its 200 degrees of temperature. This temperature of approximately 200 degrees

REGULATOR

TO NO I COIL

at the outlet underneath the car assures a temperature of 210 degrees to the outlet pipe just inside the car, and about 212 degrees to the heating coil in the car.

After the steam reaches the diaphragm and bas heated it to the point where it has completely closed the valve S, it takes about one-half minute for it to cool to 200 degrees, let in steam again, and adjust itself to a point where it will continue indefinitely to let just enough steam pass through the valve S to maintain a constant temperature of slightly more than 200 degrees around itself; this condition will remain as long as steam is in the train pipe and regardless of what the train-pipe pressure may be.

The difference between the 212 degrees temperature of the heating pipes inside the car and the 200 degrees temperature at the thermostat at the very outlet of the apparatus is because of the casing containing the thermostat having been purposely made quite open at the bottom immediately under the

FROM NOI COIL

No. 122 Valve (No. 1 Style)

No. 122 Valve (No. 2 Style)

Fig. 7 Sectional Plan View of Two Connected Cut-Out Valves; in Multiple
Regulation (Chicago Car Heating Co.)

Note.-The drainage hole shown in No. 2 style is the only difference between that and
No. 1 style, except shape of the outside of body.

thermostat, to avoid clogging the outlet with ice and to permit of the prompt cooling action of the air coming in contact with the thermostat.

When steam first enters the cold apparatus, of course the diaphragm E is cold and in a contracted condition, and the valve S is wide open, therefore steam from the train pipe blows straight through the valve S and through the heating pipes until it reaches the diaphragm E in the outlet, when immediately the expansion of the diaphragm and its operation of the valve S reduces the supply to strictly atmospheric pressure.

The reason that no appreciable pressure is present in the radiating pipes during the short time the train-pipe pressure is blowing freely through the automatic valve S before the diaphragm E becomes heated, is because the high-pressure passage through the valve disc N is purposely reduced to % of an inch in diameter, and as the radiating pipes are usually not smaller than 11⁄2 inches, they have therefore about sixteen times the area of the steam passage through the disc N.

6. Multiple Regulation.-Reference has been made to the use of more than two coils, or sets of heating pipes, in a car-more than two coils frequently being placed on each side of a car; any one or all of the coils may have the

Fig. 8. Plan View of Vapor Heating Equipment of a Coach; Multiple Regulation (Chicago Car Heating Co.)

Two separately controlled coils of two pipes each are used on each side of the car. This arrangement of heating surface and cut-out valves permits of the exact regulation of the temperature in car in the following proportions of the total heating capacity of the system: 25%, 50%, 75% or 100%.

vapor cut in or cut out, as the temperature of the car may require; there is a cut-out valve for each of these coils, but however many coils and cut-out valves there may be, only the usual number of vapor regulators is necessary- one on each side of the car, to furnish the vapor for all coils on its side. Where one regulator supplies vapor for two or more coils it is termed multiple regulation. It is best described by reference first to the plan view in section of the "multiple" arrangement of the cut-out valves for one side of the car. See Fig. 7. Two cut-out valves are here shown, to govern the supply of vapor to two individual sets of heating pipes; the cut-out valves are shown to be close together, but this need not be the case, although they must be connected directly with each other by a single pipe, attached as shown in the cut.

Assuming that both coils are to be used: vapor from the regulator enters the left-hand cut-out valve from below, as indicated, flowing in the usual direction to the first set of the heating coils as the arrows point-and after circulation returning as usual to the right-hand chambers of the cut-out valve body; but here the difference from the single-coil style appears; instead of the vapor being discharged from this point (by way of the regulator), it flows through the connecting pipe to the common receiving chamber of the right-hand cut-out valve, and, in the course traced by the arrows, to and through the second set of heating pipes, or coils, returning to the chambers of the right-hand cutout valve marked in the cut "to regulator," from which the vapor and water of condensation is discharged in the usual manner.

Suppose the weather has moderated and we wish to shut off vapor from the coil connecting with the left

hand cut-out valve; by closing that valve its connecting coil will be cut out, as has previously been explained, but the one-fourth turn of the winged valve diverts the vapor immediately through the direct connection pipe to the receiving chamber of the right-hand cut-out vaive, from which the vapor will be supplied to the heating pipes of the second coil, as understood; or, the lefthand coil may be operated and the right-hand cut-out valve be closed, and it can be seen on the cut that the discharge from the coils supplied through the left-hand cut-out valve would pass in a short-circuit through the right-hand

Fig. 9. Sectional Plan View of Three Connected Cut-Out Valves; Multiple
Regulation. Combination Parallel and Series.

cut-out valve and to the regulator for final discharge, without entering the second coil; or, again, both cut-out valves may be closed, and there will be a complete short-circuit through both cut-out valves, in practically the same way as described in cutting out the single-coil system. The drainage hole indicated in the middle wall of the right-hand cut-out valve is provided to get rid of the excess of condensation from the first coil and prevent its being carried with the vapor into the second set of heating pipes.

Fig. 8 is a plan view of the usual arrangement of the valves and piping for multiple regulation on coaches and chair cars. Cars with several compart

ments may have any number of heating coils, but all supplied from the two regulators, only.

Fig. 9 represents a unit of three cut-out valves, governing three individual heating coils-referred to as in "combination parallel and series." The cutout valves are the same as already described, and the arrows on the cut will enable the observer to follow the courses of the vapor; the arrangement is clever in the several different combinations that are possible.

As the cut-out valve has ports available on both sides, front and bottom, it is possible to use a number of heating sets in any location and provide for their convenient control by various arrangements and connections of the cut-out valves.

Examination Questions and Answers.

TRAIN STEAM AND HOT-WATER HEATING.

(PART 4, SECTION 2.)

1. Q.-What standards used in all system of present-day train heating by steam on American railroads are made practically alike?

A. The train pipe, hose and hose couplings, the inside diameter of train pipe and hose, location of train-pipe ends and the contact faces and connecting ports of hose couplings. (Art. 1.)

2. Q.-Why are these standards adhered to?
A. For convenience in the interchange of cars.

(Art. 1.)

3. Q.-In the "straight" vapor heating equipment of the Chicago Car Heating Co., how is the vapor admitted from the train pipe to, or cut off from, each coil or set of pipes?

A. By a single valve. (Art. 2.)

4. Q. Are there any other devices within the car for operating this style of train heating?

A.-No, the two vapor cut-out valves, one on each side of the aisle, are the only man-operated valves in the entire heating equipment of the car, excepting the common end or train-pipe valves. (Art. 2.)

5. Q. How is the heating vapor admitted to either or both sets of coils? A. The handles of either or both vapor cut-out valves are turned fully to the open position. (Art. 2.)

6. Q.-If it is desired that one of the coils remain cold, what should be the position of the valve handle?

A.—It should remain fully in the position marked "shut." (Art. 2.)

7. Q.-Why, with this system of vapor heating, is there no ordinary possibility of the heating pipes freezing up in extremely cold weather after the source of steam supply has been cut off?

A. Because the outlet from the heating pipes is always open to the atmosphere. (Art. 3.)

8. Q.-When the train pipe is charged with steam, and it is desired to throw any particular heating coil out of service to lessen the temperature of the car, does closing the cut-out valve stop the operation of the vapor regulating valve, and if not, what is the effect?

A.—No, the route of the vapor is simply short-circuited by cutting off connections from the pipes leading to and from the heating coils with the cut-out valve, and a short inter-connection is established in the cut-out valve from one to another of the two pipes leading to the regulator, thereby confining the circulation practically to the pipes underneath the car. (Art. 3.)