Assuming the life of heart pine poles to be twelve years (instead of twenty years), I will base a comparative proposition on that basis, taking the interest on each investment and carry it through to the expiration of thirty years. Heart pine poles for one mile of span wire construction, 104 poles to the mile, at 84.50 each, would cost $468.00, also suitable labor and material for erecting at $2.50 per pole, $260.00, or a total first cost of $728.00; to this must be added interest for thirty years at five per cent. per annum, 81,092.00, making the first investment at the end of thirty years, $1,820.00. At the expiration of twelve years the construction must be renewed at a cost of $728.00, and to this must be added interest for eighteen years at five per cent. per annum, $655.20, making the second investment at the end of thirty years cost $1,382.20.

At the expiration of twenty-four years the construction will be renewed

for the third time at a cost of $728.00, and to this will be added the interest for six years at five per cent. per annum, $218.40, making the third investment at the end of thirty years cost 8946.40, a grand total for wooden pole construction of $4,149.60.

The difference between total costs of steel and wooden pole construction, for a period of thirty years, would be $920.40 per mile, which would be more than a liberal allowance for changing span wires and other work; but assuming it would take this amount, we would stand even at the end of thirty years, and still have six years more paid for on wooden pole construction. If steel span poles are used, I would recommend for the average span of forty feet a pole weighing about seven hundred pounds made in two parts. The lower section to be constructed of six-inch extra heavy, and the upper section of five-inch standard steel pipe swaged at the joint for a distance of eighteen inches; such a pole to be twenty-eight feet long, eighteen feet for the lower and ten feet for the upper section, and provided with a cast iron and wooden pole top for the attachment of the span wires. Such poles should be provided with a wood filling to fit the bottom of the lower half to prevent it from sinking, and should be set six feet in the ground, with a rake of ten inches from the perpendicular to allow

for being straightened when under strain. The average size of the hole to be dug would be twenty inches in diameter with a depth of a little over six feet, requiring (after the pole is inserted) a mixture of about onehalf cubic yards of concrete, composed of one part of Portland cement, two parts of sharp sand, and four parts of broken rock. The cement should be given at least three days in order to set firmly before attaching the span wires. Whenever it is practicable to allow poles to bear 'against the curbing this should be taken advantage of, as it affords an efficient stay to assist the pole in resisting the strain. Should it not be possible to secure use of the curb (or paving) a good sized rock, having a bearing surface of about one square foot, would assist very much and keep the pressure from cracking the cement.

If wooden poles are used where it is necessary to make neat appearing and substantial construction, I would recommend for the average span of forty feet, a long leaf yellow pine pole dressed and chamfered, thirty feet long, sawed square, 11 inches by 11 inches at the base, and 7 inches by 7 inches at the point, free from sap, rot or knots, and corners evenly chamfered one and one-half inches, beginning at a point fourteen feet from the base, and terminating in an octagonal form and roofed evenly for a space of three inches.

In setting wooden poles where concrete is not used (and I do not consider it necessary), a great deal depends upon the soil encountered. While it is necessary to use very little prepared material for filling in some localities, it will take a quantity in others. I will mention what would be required in a soil of a medium clayey character which would probably meet the average condition. Poles should be set six feet in the ground with a rake of twelve inches from the perpendicular to allow for being straightened when under strain, and the hole should be dug to a vertical depth of six feet (or more, if necessary, to allow the pole to stand a given height above the track) in the ground and should be about two feet square at the top and not less than eighteen inches at the bottom. Where it is practicable to allow poles to bear against the curbing (or paving) this should be taken advantage of, and it will not be necessary to use other material near the surface as in iron pole construction, but it will be necessary to place substantial bearing at the heel to prevent the pole from pressing through the earth. For this purpose a small quantity of coarse broken stone or brick-bats will answer every purpose, and where this is not easily obtainable, and the earth is soft, a piece of plank twelve inches wide by three inches thick, by four feet long, sharpened and driven in the earth to a depth of about two feet at the back and base of the pole, will give good results.

Whenever it is necessary to erect poles in the absence of substantial material at the surface, such as paving or curbing, I would recommend that the base of the pole be well rammed with broken rock for a distance of eighteen inches, taking pains that the greater quantity is placed at the back where the presure is greatest, and leaving a small quantity in front where no pressure takes place. The space to within twenty inches of the top may be filled with earth taken from the hole and well

rammed. To prevent the pole from yielding at the surface a breast plank of oak (or cypress) timber 3 inches by 12 inches by 6 feet should be placed and spiked in front of and at right angles to the pole about eight inches under the surface of the ground, which would make a suitable bearing surface, and resist the span wire strain. About twenty inches from the top and in front of the breast plank, the hole should be filled and well rammed with the same material as is used at the base of

the pole. The necessary quantity of broken rock required would be about two-tenths of a cubic yard to a pole.

Poles of wood or steel which may be used for holding strains at curves should necessarily be heavier than those used for straight line construction, and should also be set at a greater depth in the ground. Steel poles of proper dimensions for curve construction should be made in two joints and constructed on the same principle as the straight line pole, excepting with heavier dimensions of pipe. A steel pole for curve construction should be twenty-nine feet long, made of six inch and seven inch extra heavy pipe, the larger section to be nineteen feet long, and the smaller section to be ten feet long, and made to weigh 1050 lbs. Such poles should be set seven feet in the ground, and raked ten inches from the perpendicular in a direction radiating from the central point of curve where the strain is required. The filling necessary would be the same as specified for straight line iron pole construction.

Wooden poles for curve construction, should be made similar to those specified heretofore for straight line construction, excepting the dimensions of such poles should be thirty-one feet long by 14 inches by 14 inches at the butt, 9 inches by 9 inches at the top, chamfered from a point fourteen feet from the base to the point terminating in an octagonal form and roofed evenly for a space of three inches. Such poles should be set seven feet in the ground and raked twelve inches from perpendicular in a direction radiating from the center of the curvature where strain is required. The hole should then be entirely filled with about seven-tenths of a cubic yard of broken rock and well rammed.

The holes for eyebolts should be bored in wooden poles before their erection and should be bored so that the bolt will incline slightly downward towards the eye to prevent the water from flowing in and rotting the top of the pole. The correct location for eyebolt holes would be determined by the height at which the trolley wire is to be placed. Twenty-two feet from the base of the pole would be correct, assuming that we allow two feet for drop in the earbody and ear and also dip in

the span,which would make the height of trolley wire about twenty feet. To facilitate the setting of poles to a uniform height it is a good plan to place grade stakes near the location selected for poles, indicating a given height relative to the grade of the track.

Center pole construction is required in many locations and may be more adaptable than other methods, but I consider span construction better owing to its flexibility and being less unsightly. There are now on the market appliances for making bracket suspensions flexible which are an im

provement over the old type of rigid construction. One of the most practical with which I am familiar is an attachment to receive a short span of flexible wire and the ordinary straight line hangers.

Poles used for center and bracket construction should be made according to the same specifications as those used for span construction, except that an ornamental pole top would be required for the steel pole instead of an insulated one. Much can be spent on ornamentations on center and bracket construction, but it always occurred to me that the most practical is ornamental enough, and places the cost where it will do the most good. For the bracket arm a 11⁄2-inch pipe of the required length, attached to a malleable iron collar, made in halves, and encir

cling the pole, and supported by truss rods leading from the end and center of the arm to near the top, makes an excellent and neat appearing construction.

Wherever guard wires are required, it will be necessary to leave about two feet additional space on the top of the pole above where the trolley span wires are attached, for the attachment of the guard wire span. It would hardly be practicable to provide an insulated pole top to provide for both span wires, so the trolley span would be supported by means of a wrought iron clamp collar encircling the pole at the proper point, and provided with suitable insulating fastening. I do not especially approve of this method of construction (as I do not favor guard wires), but I would recommend it where it is compulsory to erect guard wires.

All poles should be painted with one coat before their erection, as it affords better opportunities to carefully apply the priming coat, and at less expense than after the poles are set. A paint of dark green, composed of a graphite mixture, I find to wear well, and although it costs more than some other paints it has better lasting qualities, especially in iron work. A second coat of this paint after the poles are erected will cover marred places made necessary in setting, and will look well and last for at least two years.

Span wires necessary for trolley suspension should be of flexible steel, five-sixteenths inch in diameter, composed of seven strands of No. 12 galvanized wire, and when under strain with conditions of pole setting as I have stated, would have a tension of about 750 lbs. when erected. I have allowed eighteen inches for sag in the span, but it probably would not be over twelve inches at the time the wire is first suspended; yet it will gradually sag more as the wire stretches and the poles spring or yield in the ground; so that if a forty-foot span is attached twentytwo feet above the rail surface, the trolley wire within the course of a year would measure approximately twenty feet above the rail.

Where wooden poles are used (or wooden pole tops for steel poles), the ordinary % by 12-inch eye bolt, threaded about four inches, answers every purpose for the attachment of the span wires, and other more expensive devices used for the same purpose are not necessary. Poles, when properly set, will bear a given strain on the span wires for many years without much yielding, consequently an adjustable device is rarely if ever used. Hard drawn copper trolley wire, of No. 1-0 B. & S. gauge, has been found to be the most practical dimension of wire, and is generally considered a standard for most trolley construction; therefore, overhead appliances are made of various manufacture to meet such requirements. There has been a trolley wire recently manufactured in the form of a figure 8, which is now in use on some roads, and has given very good results. Where this wire is used it leaves a perfectly unobstructed surface for the trolley wheel, and gives greater current-carrying capacity; but in modern construction the hanging appliances have reached such a degree of perfection that the round wire can be used with equally as good results; and as the trolley wires on