Internal Combustion Engines direct connected or with belt drive are particularly adapted to operating centrifugal pumps, especially for railway water service. Considering power costs alone it is undoubtedly the most economical power that can be used, except where cost of attendance may be eliminated through automatic electric drive.

The Steam Turbine has proven a satisfactory method of operating centrifugal pumps in some cases but there are but few points where it could be used in railway water service. By an adjustment of the governor, the speed of the turbine can be readily altered to suit the varied demands made upon the pump. The steam turbine is efficient under partial loads.

The use of the steam engine for driving centrifugal pumps used in railway water service is limited and could be operated economically only where the exhaust steam was required for other purposes or perhaps where steam was available without the necessity for constructing a boiler plant.

Efficient Methods of Installation

To obtain efficient operation a special study must be made of each particular installation. Conditions under which pumping units operate vary to considerable extent and no set rules may be laid down to fit all conditions. The following suggestions are offered as applicable to general conditions covering centrifugal installations.

A certified characteristic curve of the pump at the speed recommended by the manufacturers should be furnished and studied carefully, special attention being given the following points:

(1) The unloading or non-overload feature in which the power is not increased materially should the head be reduced.

(2) The efficiency at various heads.

The horizontal, split casing type with enclosed impeller is recommended where conditions are adapted to its use as it presents the most accessible form of construction for inspection and repairs.

The bearings should be of the ring oiling type and provided with drip pockets connected to a drain to carry away the slight leakage that should be permitted through the stuffing boxes and glands.

A flexible coupling should be used on all direct connected units to connect the pump with the prime mover as this type of coupling permits for slight inaccuracies in the alinement of the shafts and insures cool bearings.

A check and gate valve should be placed on the discharge line near the pump. The check valve is to protect the pump from water hammer; the gate valve to regulate the discharge of the pump and to permit its removal without emptying the discharge line.

If a centrifugal pump is required to draw water from a single driven well, the suction pipe should be dropped down inside the well casing and the top of the casing should not be closed but left open, so that the air can have free access to the surface of the water.

The pump should be placed as near to the source of supply as possible, especially when operating with a suction lift.

In order to keep the suction line full of water, a foot valve should always be installed on the end of the suction pipe.

General Practice

The general practice is best represented by use of belt driven pumps with internal combustion engine using oil for fuel. Depending upon the cost of fuel as compared to cost of power, the internal combustion fuel oil engine or electric motor is preferable as power unit. Transmission other than belting has not been generally used by Railways. Silent chain drive appears to have an advantage in compactness of units and low transmission losses, but is largely offset by excessive first cost for the smaller installations. The use of indirect connected centrifugal pump usually arises from the necessity of putting the pump within reasonable suction lift of supply and keeping the prime mover, particularly, electric motors above possible extreme floods.

STANDARDS

C. R. KNOWLES, Chairman; R. C. BARDWELL, Sub-Committee.

During the past year the Committee has given careful consideration to the adoption of standard specifications covering cast iron water pipe and special castings, and standard specifications for hydrants and valves. The conclusion reached was that the standard specifications of the American Water Works Association were complete in every detail and so well established that practically all cast iron pipe specials, valves and hydrants now used by railroads were furnished under these specifications. Therefore, upon the recommendation of the Standardization Committee, the Board of Direction instructed the Committee to present these specifications to the Association for approval.

Tables of sizes, classification, and illustrations may be obtained in pamphlet form from the Secretary of the American Water Works Association, 153 West 71st Street, New York City.

The specifications follow:

STANDARDS FOR CAST IRON WATER PIPE

(Adopted by the American Water Works Association May 12, 1908. Reprinted by

permission.)

STANDARDS FOR HYDRANTS AND VALVES

(Adopted by the American Water Works Association June 24, 1912. Revised June 9, 1916. Reprinted by permission.)

STANDARD SPECIFICATIONS FOR CAST IRON PIPE AND SPECIAL CASTINGS

Description of Pipes.

Section 1. The pipes shall be made with hub and spigot joints and shall accurately conform to the dimensions given in Tables Nos. 1 and 2. They shall be straight and shall be true circles in section, with their inner and outer surfaces concentric, and shall be of the specified dimensions in outside diameter. They shall be at least 12 ft. in length, exclusive of socket.

Pipes with thickness and weight intermediate between the classes in Table No. 2 shall be made of the same outside diameter as the next heavier class. Pipes with thickness and weight less than shown by Table No. 2 shall be made of the same outside diameter as the Class A pipe; and pipes with thickness and weight more than shown by Table No. 2 shall be made of the same outside diameter as the Class D pipe.

All pipes having the same outside diameter shall have the same inside diameter at both ends. The inside diameter of the lighter pipes

of each standard outside diameter shall be gradually increased for a distance of about 6 inches from each of the pipe so as to obtain the required standard thickness and weight for each size and class of pipe.

For pipes of each size from 4-inch to 24-inch inclusive, there shall be two standards of outside diameter, and for pipes from 30-inch to 60-inch inclusive, there shall be four standards of outside diameter, as shown by Table No. 1.

For pipes 4-inch to 12-inch inclusive, one class of special castings shall be furnished, made from Class D pattern. Those having spigot ends shall have outside diameters of spigot ends midway between the two standards of outside diameter as shown by Table No. 1, and shall be tapered back for a distance of 6 inches.

For pipes from 14-inch to 24-inch inclusive, two classes of special castings shall be furnished; Class B special castings with Classes A and B pipe, and Class D special castings with Classes C and D pipes; the former shall have cast on them the letters "AB" and the latter "CD." For pipes 30-inch to 60-inch inclusive, four classes of special castings shall be furnished, one for each class of pipe, and shall have cast on them the letter of the class to which they belong.

Allowable Variation in Diameter of Pipes and Sockets.

Section 2. Especial care shall be taken to have the sockets of the required size. The sockets and spigots will be tested by circular gauges, and no pipe will be received which is defective in joint-room from any cause. The diameters of the sockets and the outside diameters of the spigot ends of the pipes shall not vary from the standard dimensions by more than .06 of an inch for pipes 16 inches or less in diameter; .08 of an inch for 18-inch, 20-inch and 24-inch pipes; .10 of an inch for 30-inch, 36-inch and 42-inch pipes; .12 of an inch for 48-inch, and .15 of an inch for 54-inch and 60-inch pipes.

Allowable Variation in Thickness.

Section 3. For pipes whose standard thickness is less than 1 inch, the thickness of metal in the body of the pipe shall not be more than .08 of an inch less than the standard thickness, and for pipes whose standard thickness is 1 inch or more, the variation shall not exceed .10 of an inch, except that for spaces not exceeding 8 inches in length in any direction, variations from the standard thickness of .02 of an inch in excess of the allowance above given shall be permitted. For special castings of standard patterns a variation of 50 per cent greater than allowed for straight pipes shall be permitted.

Defective Spigots May Be Cut.

Section 4. Defective spigot ends on pipes 12 inches or more in diameter may be cut off in a lathe and a half-round wrought-iron band shrunk into a groove cut in the end of the pipe. Not more than 12 per cent of the total number of accepted pipes of each size shall be cut and

banded, and no pipe shall be banded which is less than 11 feet in length, exclusive of the socket.

In case the length of a pipe differs from 12 feet, the standard weight of the pipe given in Table No. 2 shall be modified in accordance therewith.

Special Castings.

Section 5. All special castings shall be made in accordance with the cuts and the dimensions given in the tables forming a part of these specifications.

The diameters of the sockets and the external diameters of the spigot ends of the special castings shall not vary from the standard dimensions by more than .12 of an inch for castings 16 inches or less in diameter; .15 of an inch for 18-inch, 20-inch and 24-inch; .20 of an inch for 30-inch, 36-inch and 42-inch and 24 of an inch for 48-inch, 54-inch and 60-inch. These variations apply only to special castings made from standard patterns.

The flanges on all manhole castings and manhole covers shall be faced true and smooth, and drilled to receive bolts of the sizes given in the tables. The manufacturer shall furnish and deliver all bolts for bolting on the manhole covers, the bolts to be of the sizes shown on plans and made of the best quality of mild steel, with hexagonal heads and nuts and sound, well-fitting threads.

Marking.

Section 6. Every pipe and special casting shall have distinctly cast upon it the initials of the maker's name. When cast especially to order, each pipe larger than 4-inch may also have cast upon it figures showing the year in which it was cast and a number signifying the order in point of time in which it was cast, the figures denoting the year being above and the number below, thus:

etc., also any initials, not exceeding four, which may be required by the purchaser. The letters and figures shall be cast on the outside and shall not be less than 2 inches in length and % of an inch in relief for pipes 8 inches in diameter and larger. For smaller sizes of pipes the letters may be 1 inch in length. The weight and the class letter shall be conspicuously painted in white in the inside of each pipe and special casting after the coating has become hard.

Allowable Percentage of Variation in Weight.

Section 7. No pipe shall be accepted the weight of which shall be less than the standard weight by more than 5 per cent for pipes, 16 inches or less in diameter, and 4 per cent for pipes more than 16 inches in diameter, and no excess above the standard weight of more than the given percentage for the several sizes shall be paid for. The total weight to