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Assembling Steel.

camber until all tension chord splices are fully riveted and all other truss connections pinned and bolted. Rivets in splices of butt joints in compression members shall not be driven until the span has been swung. Splices and field connections shall have one-half of the holes filled with bolts and cylindrical erection pins (half bolts and half pins) before riveting. Splices and connections carrying traffic during erection shall have three-fourths of the holes so filled.

Fitting up bolts shall be of the same nominal diameter as the rivets, and the cylindrical erection pins shall be 3b-inch larger. Riveting.

. 14. Riveting preferably shall be done with pneumatic riveters and buckers. Rivets larger than 78-inch in diameter shall not be driven by hand. Connections shall be accurately and securely fitted up before the rivets are driven. Light drifting will be permitted to draw the parts together, but drifting to match unfair holes will not be permitted. Unfair holes shall be reamed or drilled. Rivets shall be heated to a light cherry color, and in driving shall be upset to completely fill the holes. Heads shall be full and symmetrical, concentric with the shank, and shall have full bearing all around. They shall be the same shape and size as the heads of the shop rivets. Rivets shall be tight and shall grip the connected parts securely together. No recupping or caulking will be permitted. Rivets shall not be overheated or burned. In removing rivets, the surrounding metal shall not be injured; if necessary, such rivets shall be drilled out. Cup faced dollies, fitting the head closely to insure good bearing, shall be used.

Bolted Connections.

15. In bolted connections, bolts shall be drawn up tight and threads burred so that nuts cannot become loose.

Pin Connections.

16. Pilot and driving nuts shall be used in driving pins. They will be furnished by the Company and shall be returned to the Company on completion of the work. Pin nuts shall be screwed up tight and threads burred so that the nuts cannot become loose.

Deck.

17. Where so specified, the ties, guard timbers, guard rails, fire decking, concrete decking, waterproofing, ballast, and deck planking, and the track rails and tie plates, shall be placed by the Contractor. The timber deck, untreated, shall be framed and placed in accordance with the Company's plans. The ties shall be framed to give a full and even bearing on the girders and under the rails. The guard timbers shall be dapped and framed to a snug fit over the ties and fastened as shown on the plans. If treated timber is used, the Company will deliver it properly framed to the Contractor. If necessary to do any framing or cutting of treated timber, the resulting surfaces shall be given a brush treatment with wood preservative, as directed by the Engineer. Where concrete decking is used, or waterproofing is required, the specifications therefor will be furnished by the Company.

Misfits.

18. Corrections of minor misfits and a reasonable amount of reaming will be considered as a legitimate part of the erection. Any error in shop work which prevents the proper assembling and fitting up of parts by the moderate use of drift pins, and a moderate amount of reaming and slight chipping or cutting shall immediately be reported to the Inspector, and his approval of the method of correction obtained. The correction shall be made in the presence of the Inspector, who will check the time expended. The Contractor shall render within thirty days an itemized bill for such work of correction for the approval of the Engineer.

Painting

19. Heads of field rivets shall be painted by the Contractor. This painting shall not be done until the Inspector has examined the rivets and found them satisfactory. The tops of stringers and girders which are to carry ties shall be given one coat of field paint.

If the field painting is to be done by the Contractor, the specifications therefor will be furnished by the Company. Removal of Old Structure and Falsework.

20. The Contractor shall dismantle the old structure and falsework and load the material on cars for shipment, or pile it neatly at a site immediately adjacent to the tracks, at a convenient elevation for future handling, as directed by the Engineer. When the old structure is of iron or steel and is to be used again, it shall be dismantled without unnecessary damage and the parts match-marked.

21. The Contractor shall remove the piling to the surface of the ground and all debris and refuse resulting from his work, leaving the site in good condition. Superintendence and Workmen.

22. During the entire progress of the work the Contractor shall have a competent foreman or superintendent in personal charge of the work. Instructions given to the foreman or superintendent shall be considered as given to the Contractor. All work shall be done by skilled, competent workmen.

Interference With Traffic.

23. The Contractor shall conduct his work in such a manner that the track, while in service, will be safe and clear for the passage of trains. Tracks shall be disturbed or removed for the prosecution of the work during such times only as allowed by the Company. While the Contractor is actively engaged in the erection, trains will be required to approach the bridge prepared to come to a stop before crossing and will proceed only on signal. During the time the Contractor operates his equipment on the tracks or has occasion to make the tracks unsafe for the operation of trains, his operations will be in charge of a conductor or pilot who will arrange and control the train movements.

Company Equipment.

24. When the agreement provides that the Company shall furnish equipment to the Contractor, such as flat cars, water cars, bunk cars, etc., the Contractor shall repair all damage to such equipment furnished for his use and return it in as good condition as when he received it.

Work Train Service.

25. When under the contract work train or engine serviee is furnished the Contractor without charge, the Contractor shall state in his bid the number of days such service will be required. Any excess over the time specified in this bid shall be paid for by the Contractor at the Company's schedule of rates.

Risk.

26. The Contractor shall be responsible for loss of or damage to materials and for all damage to persons or property and for casualties of every description caused by his operations during the progress of the work. Injuries or losses due to events beyond the control of the Contractor shall not be borne by him unless they occurred because of his dilatory methods in handling the work, extending the time beyond the time limit designated in the contract.

Inspection.

27. The work shall be subject at all times to inspection by the Engineer.

Laws and Permits.

28. The Contractor shall comply with Federal, State and local laws, regulations and ordinances, and shall obtain at his own expense the necessary permits for his operations.

SPECIFICATIONS FOR MOVABLE RAILWAY BRIDGES—1922

BURTON R. LEFFLER, Chairman;
W. S. BOUTON,
M. F. CLEMENTS,
O. F. DALSTROM,
THOMAS EARLE,
R. L. HUNTLEY,

P. G. LANG, JR.,
ALBERT REICHMANN,
I. L. SIMMONS,
I. F. STERN,
J. A. L. WADDELL,

Sub-Committee.

FOREWORD

The purpose of the Committee which wrote these specifications was to formulate specific and detailed rules for the design and manufacture of movable railway bridges, as a guide to both the designer and the shop, rather than to confine the specifications to a statement of principles or to limit them to rules defining the duties of the contractor. The intention was to describe the best general practice in the accepted types now in use for standard American and Canadian railways and to advance the causes of good design and workmanship. The requirements of light and branch railways and foreign practice have not been considered.

The specifications in preliminary form were printed in Bulletin No. 204 and in the Proceedings, Vol. 19, and discussions and suggestions were invited.' The discussions received were printed in Bulletin No. 228 in 1920. These, together with later written and verbal discussions, were considered by the Committee in the final revision.

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Contents Section Subject

Information to be given Bidders.
1 Proposals and General Requirements.
2 General Features of Design.....
3 Loads, Unit Stresses, and Proportioning of Parts.
4 Details of Design
5 Wire Ropes and Attachments.
6 Power Equipment:

a. General Requirements
b. Steam
c. Internal Combustion

d. Electric 7 Materials:

a. Cast Steel
b. Forged Steel
c. Tool Steel
d. Bronzes

Babbitt Metal
8 Workmanship
9 Erection

Index.

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e.

Information to Be Given Bidders

Articles A copy of the contract form.....

102 Will there be separate contracts for the different parts of the superstructure?

102 The normal time for opening the bridge after the ends are released (for both main and auxiliary powers)......

103 The house for the operator and for the signal devices shall be built by whom? ..

107 Warning lights required.

109 Will the Company furnish the deck and track material?.

113-; The type of movable bridge to be used....

201 Shall the auxiliary power be hand or mechanical?.

204 Kind of heating apparatus to be installed by the Company.. 207 Shall an overhead crane be installed in the machinery house?.. 207 The type of center to be used in swing bridges....

210 Design for rail-end connections....

401 Company specifications for concrete.

409 Kind of power to be used.....

601 Kind of electrical control (manual or automatic)

605 Method of operating service brake...

606 Shall a whistle or an electric horn be installed?.

607 Number of boilers and kind of fuel......

610 Height of boiler stack, if fixed by ordinance or special conditions... 610 Is river water fit for boiler use?.....

613 Kind of fuel for internal combustion engines..

615 Electric power service characteristics..

627-628 Data for submarine cables.....

664 Electric lighting service available..

666

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