. The Street railway journal . for a newpole line, or $ Adding the expense of re-aligningspan wires, $240 per mile, will give a total expenditure at the end of thirty-three years of $3,522, and with a deprecia-tion per year of $ The comparison now stands: Total cost of steel polesfor thirty-three years, $2,, and lor wooden poles,$3,522. This gives a difference in favor of the steel polesof $1, per mile. The depreciation rate of $74-37for steel poles and $ f°r the wooden poles gives adifference of $ per annum per mile. If interest wascharged against the inve
. The Street railway journal . for a newpole line, or $ Adding the expense of re-aligningspan wires, $240 per mile, will give a total expenditure at the end of thirty-three years of $3,522, and with a deprecia-tion per year of $ The comparison now stands: Total cost of steel polesfor thirty-three years, $2,, and lor wooden poles,$3,522. This gives a difference in favor of the steel polesof $1, per mile. The depreciation rate of $74-37for steel poles and $ f°r the wooden poles gives adifference of $ per annum per mile. If interest wascharged against the invested amounts for the term of lifeof property, it would reduce somewhat the showing infavor of the steel pole, but in any method of figuring therelative values from an investment standpoint the show-ing is greatly in favor of the iron pole line. From an en-gineers standpoint the superiority of the iron pole presentsmany advantages besides the lasting qualities, which di-rectly affect the operation of the road. The item of re-. FIG. 1.—WOODEN POLES AND METHODS OF TESTING equipping and renewing, which involves the adjustmentof span wires and trolley wires, is directly contingent onthe removal of poles, and should properly be chargedagainst the wooden pole line, since it is obviated by the useof iron poles. The expense of keeping a trolley line tautand in good alignment, which insures the trolley keepingcontact with the trolley wire, is largely dependent uponthe rigidity of the pole line, and it is well known that eightyears ago iron poles were manufactured in order to gainthese results. As previously stated, however, certain local conditionsmay be favorable to the use of wooden poles, and the es-sential features of a good wooden pole line will now beconsidered. WHAT CONSTITUTES A GOOD WOODEN POLE LINE Wooden poles are divided into classes dependent ontheir form, growth and symmetry. The woods usuallychosen are chestnut, hard pine and cedar. As a rule, the 278 STREET RAILWAY JOU
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
