APPENDIX D CROSSING REGULATIONS 207 



of rails or other wires must be given for every 20 ft. or fraction thereof additional 

 length of span. The words " low-tension," as here used, to mean conductors for 

 telegraph, telephone, and kindred signal work, as well as conductors connected with 

 grounded secondary circuits of transformers below 350 volts. 



Kb All primary conductors, ungrounded secondaries, and railway feeders to be 

 maintained at least 30 ft. above the top of rail except where special provisions are 

 made for trolley wires. 



Kc High-tension conductors, those between which a potential of 10,000 volts or 

 over is employed, to be maintained at least 35 ft. above the top of rail. 



L Clearances. 'Safe clearances between all conductors to be maintained at all 

 times. The following distances to be provided wherever possible; at least 3 ft. clear- 

 ance from low-tension wires; at least 5 ft. between low-tension wires, primaries, 

 ungrounded secondaries, and railway feeders employing less than 10,000 volts; at 

 least 10 ft. between high-tension wires and all other lines. 



M Guy wires. 'Guy wires at railway crossings to be at least as strong as 7-strand 

 No. 1'6 'Stub's or New British 'Standard gauge galvanized steel wire, and to be clearly 

 indicated as guy wire on the drawing accompanying the application. One or more 

 strain insulators to be placed in all guy wires; the lowest strain insulator to be not 

 less than 8 ft. above the ground. 



Na Wires and other conductors. Where open telephone, telegraph, signal or 

 kindred low-tension wires are strung across a railway this stretch to consist of 

 copper wire, or copper-clad steel wire, not less than No. 13 New British Standard 

 .gauge, -09'2 in. in diameter. Wire is to be securely tied to insulators by a tie wire not 

 less than 20 in. in length and of the same diameter as the line wire, 



Nb Where No. 9 iB.W.G., or larger, galvanized iron or steel wire is employed in 

 a circuit, and where there is no danger of deterioration from smoke or other gases, 

 the use of this wire may be continued at the crossing. 



Nc Where a number of ru'bber-covered wires are strung across a railway they 

 may be made up into a cable by being twisted on each other or otherwise held together 

 and the whole securely fastened to the poles. 



Nd Wires or other conductors for the transmission of electrical energy for pur- 

 poses other than telegraph^ telephone, or kindred low-tension signal work, to be com- 

 posed of at least seven strands of material having a combined tensile strength equiva- 

 lent to or greater than iNo. 4 B. & S. gauge hard-drawn copper wire. These con- 

 ductors to be maintained above low-tension wires at the crossing, to be free from 

 joints or splices, and to extend at least one full span of line beyond the poles or 

 towers at each side of the railway. 



Ne Wires or other -conductors subject to potentials of 10,000 volts or over, to be 

 reinforced by clamps, servings, wrappings, or other protection at the insulators to 

 the satisfaction of the Engineer of the Board. 



Nf Conductors for other than low-tension work to have a factor of safety of 2 

 when covered with ice or sleet to a depth of 1 in. and subjected to a wind pressure 

 of 8 pounds per square ft. on the ice-covered diameter. 



Ng All conductors to be dead-ended or so fastened to their supporting insulators 

 at each side of the crossing that they cannot slip through their fastenings. 



Positions of wires. Wires or conductors of low potential to 'be erected and 

 maintained below those of higher potential which may be attached to the same poles 

 or towers. 



P Trolley wires. Trolley wires at railway crossings to be provided with a trolley 

 guard so arranged as to keep the trolley wheel or other rolling, sliding or scraping 

 device in electrical contact. The trolley wire, trolley guard, and their supports to be 

 maintained at least 22 ft. 6 in. above the top of the rails. 



