Handbook of construction plant, its cost and efficiency
Dana, Richard Turner, 1876-1928
TABLE 10 Height in Feet Above Efficiency of Corn-Sea Level Barometer. Inches pressor, Per Cent 0.30 100.0 500 29.42 98.4 1,000 28.85 96.9 1,500 28.34 95.5 2,000 27.78 94.0 3,000 26.74 91.1 4,000 25.70 88.1 6,000 23.83 82.8 7,000 22.93 80.2 8,000 22.04 77.5 9,000 21.22 75.1 10,000 20.43 72.7 12,000 18.92 68.0 Add P I"3 TH^H^IM'CC' S w'^Sio nf w J^S'-1 P H £ |§ 1 * otqno o B d B o 1 CO LO t- O5 i-l CO < M o tiQ n ol *Q EH <D >SSftt! 0 H.2 pq CQ Q •S'c+e-Ss:! |_(K o>W ^5o5oc3fc- •gg-4->3o G'P .S |C*^ W| fp^o^^^c «fe*3 Eg « "-"• ^; g H S joousoooooo J^^^JU PH ll«P § * <M c^ e<i e<i co eo .3 P Suissead -UIOO JO 'UIBIQ -«v ' ilf!° i K PQ 3 ti M *, O CO CO O fr- ? eo'2lo'St^o6aidTH'Seo'ui^: ^ O W o K t~ H O -B <OOOIOC~M< <oeo <o^«o SG^" Q) WJ M< EM ••_(,J5 n o HH Oo^oooooooooo H cS fe »fl CO PERPENDICULAR HEIGHT, IN FEET, TO WHICH THE WATER IS TO BE PUMPED Air pre'ure at pump Cubic ft. of free air per gal. of water. Air pre'ure at pump Cubic ft. of free air per gal. of water. sis CD "0*0 3.J-; Air pre'ure at pump Cubic ft. of free air per gal. of water. Air pre'ure at pump Cubic ft. of free air per gal. of water. Air pre'ure at pump Cubic ft. of free air per gal. of water. +S SH CD 1 ^ CD c o °k£ft 1 1C t"— tN. »C 00 CO o f2 o §3 Tf CO  CO CN »C CM 12 1C O rH ^ CO 00 1C CO CO s CO Tf rt< 1C CM GO Tf CN co CO OS rH CO CO CM 1C »C 00 00 CM CO GO 00 00 O CM co 1 CO rH CO CN O CO rH CM o »c CO CM CO CO CN ** S S 3 0-csi § 13 >> O CD •*-• 1 CO CO OS 00 OS 00 rH CO rH CO CO CM O CO CM CM CM 1C CM 00 0 CO CM 00 OS OS *C CM t - rH 5 00 O 1C 3 w ~ CM N § CN O cc 0 ^ 00 CO 00 1C 00 rH CO OS CO CO CO rH CO ic oo CM B O OS CO CO O t> CM >C 1C O <N CM % ~ g % CN TH CO CO CO 0 CO 1C CO <N 00 OS rH 00 ^ OS 1C rH i5f! S 1C O CO •* CO <N o 1C CO SCM >C 00 iC CO OS 00 CO CM CM O I* 4n rH CD -rJ 0) H-J '-H ID Ci 00 •O -y 3 ftrC C 01 '11 § 1C OS CN 00 CO O 00 CM OS t^ rH CO 1C CO ^ s CO « CM ^H § 0 b- 3 0 00 r^ OS rH »C CO t~ CM CO rH >c ic o CN CO rH 0 CO O CO 00 00 O ^ « CO 0 s 1C 1C rt« l> O CM CM iC CM CO s CO O O i. Asbestos building felt and sheathing in less than ton lots costs 3½c per pound for the light material weighing from 6 to 30 pounds per 100 sq. ft., 4c per pound is charged for the heavy asbestos weighing from 45 to 56 pounds per 100 sq. ft. Mill board is made in standard sheets, 40x40 ins., and 41x40 ins. It varies in thickness from 1-32 to % in. and in weight from 2 to 27 lbs. per sheet. The net price in 100-pound lots is 5c per pound. Transite, asbestos wood, used for fireproofing, ventilators and smoke jackets, comes in standard sheets, 36x48 ins. and 42x96 ins. The  .28 .32 .36 .40 .44 .48 .52 .56 .64 .72 .80 Asbestos cements are used for covering boilers, domes, fittings, etc., and all irregular surfaces, and may be used over asbestos air cell boiler blocks, when it makes an excellent covering. When mixed with water to a consistency of mortar and applied with a trowel, it forms a light porous coating which is the most efficient non-conductor. The cost of this cement is $33.00 per ton. HANDBOOK OF CONSTRUCTION PLANT ASPHALT PLANTS ASPHALT MIXING PLANTS A semi-portable asphalt mixing plant (Fig. 15) designed to meet the requirements of paving contractors and municipal street repair work consists of a double drum dryer with cold material elevator. The dried materials are delivered into a hopper and thereby conveyed to the hot material elevator, from which they are discharged directly into the revolving screen which is located above the hot material bin. This bin is supported in a tower and from it the hot materials are delivered to a measuring box in which the materials may be either measured or weighed. The melting tanks (of one thousand gallons capacity each) are arranged in a battery of six and are provided with suitable covers, and from them the asphalt is conveyed to the bucket by the dipping process. This bucket is arranged with trolley track and each batch of asphalt Can be weighed. The mixer is provided with two sets of shafts which may be easily interchanged for mixing either binder or topping. The power plant consists of a locomotive type boiler with a 50 h.p. engine mounted thereon. The engine and boiler are mounted on skids and there are no heavy foundations necessary, thereby making the plant easy to remove. The plant has 1,000 square yards per day capacity; total weight, 63 tons; price, f.o.b. Buffalo, N.Y., $10,500. An asphalt mixer was used in Lincoln Park, Chicago, during 1910 to construct an asphalt surfaced driveway. The road was 40 ft. wide x 4,631 ft. long, and had 2 inches of asphalt on an 8 in. base of crushed stone. The total amount of asphalt was 22,318 sq. yds. The material was mixed in an asphalt mixer in the following proportions: Lbs. 1 part torpedo sand 16s 1 part bank sand 165 3 parts i^-in. stone 594 Asphalt gi Total 7 cu. ft. or 1 box 921 The total costs were as follows: Labor on stone, per sq. yd $0.498 Labor on asphalt, per sq. yd 352 Stone for base, per sq. yd 394 Asphalt material 394 Total per square yard $1.638 Labor cost of curb, per lin. ft 64 Material cost of curb, per lin. ft 21 Total cost of curb $0.85 These costs include all repairs to the plant. But no depreciation. The cost of the plant was as follows: Link Belt Co., asphalt mixer $5,590 Gasoline tractor 1,200 6-ton roller 1,800 15-ton roller 1,500 Asphalt tanks and tools 1,000 Total value of plant $11,090 ASPHALT REPAIR PLANTS The municipal asphalt repair plant of Indianapolis, Ind., is described in Engineering and Contracting, Vol. XXXI, No. 4. The plant has a capacity of 1,200 square yards of 2 in. asphalt per day, and cost $15,525. The total cost, including one 5-ton steam roller, four dump wagons, five wagons, office building, roller, stone dust and tool sheds, all tools necessary, and the preparation of the yard was $20,557.68. From June 16 to December 31, 1908, 101,743 square yards of surface mixture were turned out at a total cost of about 64 cents per square yard. One day was lost on account of rain, four days waiting for material and seven hours for repairs to plant. The cost of material used was, for California asphalt $23 per ton, for Trinidad asphalt $29 per ton, for limestone dust $3 per ton, for residuum oil (average) 5 cents per gallon, and for sand 90 cents per cubic yard. The municipal asphalt repair plant of New Orleans, La., was erected on a lot 175 ft. x 260 ft., and covers about 1,500 square feet of ground. The cost of plant was as follows: Demolition of old garbage plant buildings $475.00 Asphalt plant — Warren Bros. Asphalt Paving Co.'s contract, $16,862.50; city alterations and additions, $2,736.50; 19,599.00 Yard fences and gates $859.00 Switch tracks 1,189.00 Yard pavements and drains 6,721.00 Tower tank and filter 1,330.00 Water pipes and outlets 1,015.00 Waterhouse and platform 1,471.00 Asphalt shed 289.00 Blacksmith shop and equipment 222.00 Stable, rolling pen and wagon shed 5,311.00 Stone crusher and storage bin 1,966.00 Yard material bins 332.00 Office and store room building 5,509.00 Landing bins and roads 1,432.00 Lighting 352.00 General cleaning of premises 298.00 Total $48,370.00 In addition to 134 tools of various kinds included in the contract price, the plant is furnished with the following: 1 Rolled-mounted platform scales; 1 4-wheel hand truck; 12 wheelbarrows, 18 shovels; 10 axes; 6 picks; 8 crowbars; 8 sledge hammers; and a number of small tools. The shed tools consist of the following: 2 tool boxes; 18 street barriers; 1 8-ton steam roller; 1 3%-ton steam roller; 1 1,000-lb. hand roller; 1 fire wagon; 1 mixing kettle; 18 asphalt irons; 66 asphalt axes; 107 picks; 18 mattocks; 142 shovels; 24 wheelbarrows; 6 axes; 200 ft. of hose; 6 sledge hammers; 8 chisels; 10 iron bars; and other small tools. The testing laboratory is equipped with cement testing apparatus, oil testers, brick testers, etc. In addition, 17 mules, 3 horses, 8 sets harness, halters, blankets, etc., for the stable, and 10 wagons, 8 carts, 2 farm wagons, 1 float dray and 1 buggy were purchased. This equipment cost as follows: Live stock, harness and stable equipment $6,197.00 Rolling stock and equipment $3,180.00 Plant tools $837.00 Street tools $5,492.00 Office furniture $447.00 Laboratory equipment $1,490.00 Total $17,643.00 Additional equipment was as follows: 1 7-ton steam road roller $1,113.00 1 steel road grading machine $150.00 1 700-gallon capacity road sprinkler $396.00 Rolling stock $1,000-22 Railroad plows with extra points Wheel scrapers $140.00 Harness $139.00 Live stock $1,700.00 Total $4,704.00 ASPHALT PLANTS 33 From September 1, 1906, to August 31, 1907, supplies cost as follows: Av. Unit Cost Total Asphalt, 465.99 tons $18.50 $8,561 Fluxing oil,  River sand, 1,779 cu. yds.1.64 2,920 Tchefuncta River sand, 250 cu. 5 ds.1.60 400 Mineral dust, 321 tons. 5.50 1,764 River gravel, 554 cu. yds... 2,27 1,272 Cement, 1,936 bbls 2.04 3,944 Coal, 389 tons 2.84 1,105 Clay gravel, 3,178 cu. yds 1.50 4,786 New small granite blocks, 3,240.07 227 Old small granite blocks, 4,600.04 184 New building brick, 9,000 98 Old building brick, 8,500 25 Pine wood, 49% cords 5.68 283 Oak wood, 41% cords 6.74 280 Lake shells, 3,618 cu. yds 1.46 5.04 Brickbats, 696 cu. yds 1.48 1,032 Cast iron, 32,924 lbs 1,289 Drain pipes and Ys 3,026 lin. ft 979 Laboratory supplies Office supplies, stamps, etc 436 Engineers' supplies 606 Oats, 122,172 lbs 015 1,820 Bran, 6,600 lbs 016 66 Hay, 39 % tons 24.72 983 Stable supplies 309 Blacksmith supplies 87 $43,309 During the same period of time the plant turned out 88,947 cubic feet of wear surface which equals 49,415 square yards of 2-inch pavement. The largest day's run was 205 boxes of wearing surface mixture. One box, or 9 cubic feet, will lay 5 square yards of 2-inch pavement. 34 HANDBOOK OF CONSTRUCTION PLANT AUTOMOBILES These are of two main classes, those for transporting men, and those for materials and supplies. Passenger Cars. For use of a superintendent, the passenger automobile, enabling him to go from place to place with speed and convenience, is practically indispensable. Their first cost is known to almost everyone who reads the papers, but the cost of operation, which is the important feature, seems to be a mystery to owners until a few months after they have had their cars in commission. The medium-priced car, say from $1,200 to $1,800 for a five-passenger touring car equipped, is worth at the end of its first year a little less than two-thirds of its first cost if in proper repair, newly painted and usually with two new tires. After the first year, the rate of depreciation is a little less, say, 25 percent of the original cost when new. It is reasonably safe to figure about as follows for a standard American car: Depreciation per year 25 %-40 % Interest 6 % Repairs and painting 10%-20% Storage (garage) (if in cities) 15% -30% (Less in country) Gas oline and oil, 10,000 miles 5%-15% These figures are intended to represent average conditions, and may easily be exceeded by careless handling or rough usage, and, on the other hand, may be too high for certain conditions. The very high priced cars will not depreciate as fast as 25 percent, while the very low ones may depreciate faster than 40 percent. If given less than average use, the repair bill will be low, and the gasoline and oil costs will be reduced in proportion. If not used at all, but stored at a minimum rate of 5 percent, the above costs will foot up to 36 percent of the cost of the car new, while with very moderate usage 50 percent would seem none too high. The proper unit for gasoline cost is that of the car mile, but here it has been assumed to be on the basis of gasoline at 15 cents per gallon and twelve car miles per gallon of gasoline. I have allowed 1.5 cent per mile for oil, making 1.5 cents per mile in All, or $150 for 10,000 miles, which would be 10 percent of the first cost of a $1,500 car. If the average $1,500 car is used 200 days in the year, averaging fifty miles per day, its daily cost on the above basis will be $6.45, which, allowing for chauffeur and overhead expenses, checks with the ordinary rental charges. The automobile manufacturing industry at present (1912) is growing faster than the demand for cars, with a rapidly decreasing price for standard cars, at the same time that competition is keeping up the quality of the marketable cars. There will be, therefore, a smaller demand and lower prices for second-hand cars; hence the figures for depreciation will in the future tend to increase. The price of gasoline is not likely to be lowered, but is gradually advancing, and repair and storage rates tend to increase with the lapse of time. Consequently, the total percentage for annual maintenance cost, in terms of the selling price, is likely to grow from year to year the country over, the selling prices tending to steadily decline until they reach a standard cost of production plus standard. overhead charges and reasonable profits. At the present writing, 1914, they are still at a considerable distance from this standard point. Many figures of "sworn statements" as to repair costs have been published in the interests of the manufacturers of cars. These may be useful as advertising matter, but they are hardly a safe guide when financing a purchase. Freight Cars, Trucks. The value of an automobile truck for handling materials and supplies depends on a good many factors that are often not familiar to a contractor, especially when he has no data except those furnished him (for nothing) by the willing salesman. The motor truck has certain marked characteristics that place it in a distinct class by itself. When comparing it with two-horse wagons, these peculiarities must be considered to avoid an erroneous conclusion. The common unit of possible comparison is the ton of "live load" transported. The cost of loading and unloading may be assumed to be the same with motors as with horses. The essential factors are, therefore, as follows: W=net live load in tons, average, M=dead load of vehicle in tons, S=speed loaded in feet per minute, K=speed empty in feet per minute, D=distance of haul in feet, one way, L=lost time in one average round trip, waiting to load and unload, breakdowns, etc., in minutes, F= fixed charges per working day, such as interest, D=depreciation, S=storage, O=operating expenses per working day, such as R=repairs, m=number of minutes in the working day, R=transportation cost per ton. n,.*~a n=number of round trips per working day of m minutes. Then we have the following formulae: (1) H = time in minutes for a loaded trip, S — = time in minutes for an empty trip, H (2) LH — = actual non-productive time per round trip, KS (3) LH — = total average time for one round trip. This in L+— (1+ — ) the majority of cases must be either an integral number or an integral plus, since the truck must usually tie up for the night at one end of the trip. Average load transported per day, in tons. R = cost of transportation per ton for mw distance D W — = weight of load divided by weight of vehicle, and TUT, „. = live  eight factors composing the quantity R, and these seven formulas give us all the essential relations for determining the economic policy to be pursued for any given conditions from which the values of the eight factors can be determined. Several of these may be taken as standard, while two, namely, the practicable net load and the distance of haul, will vary with the nature of the work and the hourly conditions on the work. To make proper comparisons between an automobile truck and other means of transportation, the cost curves for each method should be plotted and the costs thus readily be estimated. Automobiles range in price from $500 for a 700-pound delivery wagon to $6,000 for a 7-ton truck. Prices as given are usually for the chassis alone and do not include the body, which latter may be had in a variety of forms at little above actual cost. Some types of body are very ingeniously designed and the removable body is of especial interest. This is made separate and of a size to suit the work it has to perform, and is mounted on rollers and can be removed from the chassis and rolled onto a hand truck or other support and while it is being loaded or unloaded the chassis is performing its work with another body of the same type. This is very valuable on short hauls, or where material which is difficult to handle is being carried, where the loading charge would be a large part of the total. Mr. Charles L. Gow, in a paper read before the Boston Society of Civil Engineers, cites an instance where the 5-14-mile road from the railroad to the work was in such bad condition and of such steep grades that 2-horse and sometimes 4-horse wagons were unable to make more than two trips per day, carrying 3,000 pounds. A steam traction engine failed of greater success on account of the bad roads and because the steep grades going up hill caused the steam dome to be flooded and going down caused the crown sheet to be uncovered. A gasoline traction engine failed because of the presence of sandy patches in the road which destroyed the tractive force of the wheels. A 2-ton 38.5 horsepower automobile truck was introduced with great success, making six trips per day over a longer but better road. However, the use of the truck on the steep, icy roads became too dangerous and was stopped during the winter. Mr. Gow says: "It is highly probable that had two of these trucks been purchased..." Aged at the beginning of the work great saving would have been effected in the cost of handling materials. Forbes & Wallace put a gasoline machine in service May 1, 1909, to deliver bundles from their department store. The result of eight months' use is as follows: Total number of bundles delivered 2,700 Expense including storage, oil, parts and labor $368.00 Tires and repairs 217.00 Gasoline 119.00 Registration 10.00 Wages 559.00 Total $1,273.00 Depreciation, 33 1/3% per annum. Cost of delivering bundles by automobile, $2.50, by horse, 9 8/10c. Four Overland delivery cars were used by the United States Mail Service at Indianapolis for eighteen months. Each car replaced three horse-driven wagons and covered sixty to seventy-five miles a day. During the winter of 1910 in New York City, a motor truck carried ten cubic yards of snow, as compared with five cubic yards carried by an ordinary contractor's wagon. The return trip from the unloading point to the dock took the motor truck on an average forty minutes, while the best record trip with a two-horse truck was one hour and twenty minutes. At the rate of 36 cents per cubic yard, the motor truck earned $7.20, while the best of its horse-drawn competitors earned $1.80. A New York contractor hauls heavy stone to the crusher and broken stone away from it. A 3-ton motor truck in one and a half days does the work that five teams took two days to accomplish. In New York City, a 5-ton truck delivered 963 tons of coal in twenty-six working days with no delay from breakdowns; it A averaged twenty-eight miles per day and thirty-seven tons per day. A 10-ton truck delivered eighty-four tons a day and covered two and a half miles on each gallon of gasoline. An industrial concern on Staten Island used one 3-ton gasoline truck, one 3-horse truck and one 2-horse truck over a round trip of twenty miles. The horse-drawn trucks made one trip each and the motor truck two trips per day. The 3-horse truck hauled by 2 tons at a cost of $10.03, the 2-horse truck hauled three tons at a cost of $13.40. The Chicago Public Library has been using six 1-ton gasoline wagons to deliver books to their branches. They were installed in November, 1904, and the following statement was estimated to April, 1909. Drivers' wages $4,000.00 Machine work $117.01 Gasoline 939.23 Parts replaced 1,304.02 Oil and grease 450.15 Tires 968.97 Parts 35.02 Waste 52.44 Painting 199.00 Supplies 210.78 Interest at 6% 1,080.00 Washing 600.00 Storage 800.00 Insurance 90.00 Total $10,846.62 Average miles per day, 33; average cost per ton mile, 18c. This service formerly cost 20c per ton mile with horse drawn wagons. The Manz Engraving Company replaced four double teams with one 3-ton truck which made two trips daily on a round trip of more than fourteen miles. Five gallons of gasoline were used per day. In the Boston American Economy and Reliability contest, held in October, 1910, for motor trucks, the cost of gasoline and cylinder In order to operate oil per ton mile ranged from $0.0068 to $0.0892 and for the twenty-eight cars the average was $0.026, with gasoline costing 16 cents and oil costing 50 cents per gallon. Standard speeds for motor trucks were formally adopted at a convention of the National Association of Automobile Manufac- turers held in 1912. Those speeds, as reported in the Power Wagon of Chicago are as follows: TABLE 16 Load Miles Load Miles Rating per Hour Rating per Hour ton 16 4% ton 9^ 15 14 13 7 12 8 11 9 I0y2 10 10 TYPES OF TRUCKS There are several types of motor dump trucks for use by contractors and others who handle material in bulk. These trucks are so made that the body, together with its load of from three to ten tons, can be raised at the front end and the load slid out or else raised vertically to a sufficient height to permit chutes to be used. One of these trucks has a body that is raised at the front end by a pair of chains moved by a train of gears driven from the transmission set of the truck. Another is simi- larly operated, except that the chains are wound up on the AUTOMOBILES 39 drums, which are worm driven from the primary shaft just back of the clutch. There is also a dump truck that is operated by compressed air. A valve on the dash is opened to admit compressed air to a long vertical steel cylinder behind the seat. This raises a plunger whose rod is connected to the top of the front end of the body, thus hoisting the body with the load. Releasing the air from the cylinder allows the body to settle back to normal position. The compressor is operated by the vehicle engine. A new and valuable feature of some of the dump trucks are the automatic tail boards with which they are equipped. These are hung on trunnions at the top and so connected to a system of toggle arms at the lower corners that they open automatically as the front end of the body is elevated, thus enabling the driver to dump the load without leaving his seat. Upon lowering the body, the tail board closes and is locked into position. Besides the trucks suitable for general contractors and builders' hauling, illustrated in Figs. 17 to 22A, there are a variety of trucks for special purposes, such as hauling lumber, refuse removal, and for department purposes. In what follows, I give such data as have been collected on the cost of motor truck operation. Costs of motor truck operation specifically for contract work are somewhat rare, but they have been obtained in two cases which follow. Operating costs as compiled by manufacturers and as given for other lines of work than contractors' hauling are, however, Nearly as serviceable, and a number of examples follow. Manufacturers' Averages. From data made public by manufacturers and covering often several years of operation, the following averages have been compiled: A tabulation compiled by one motor truck builder shows that the daily cost of a two-ton truck that averages 70 miles a day is $10.60; that of a three-ton machine averaging 62 miles a day, $12.20; of a four-ton truck averaging 55 miles a day, $13.80, and of a five-ton truck averaging 50 miles a day, $15. Another company has compiled a similar cost table covering a period of more than six years. This shows the average daily cost of running a one-ton truck to be $8.07, of a two-ton truck $10.25, a three-ton truck $11.30, five-ton truck $14.80, seven-ton truck $16.45, and of a ten-ton truck $18.50 a day. The figures given for the trucks of one to ten tons capacity include all items properly chargeable to the hauling service, both actual running expenses and overhead expenses. Drivers' wages are figured at $16 to $22 per week, gasoline at 12 cents a gallon, oil at 30 cents; garage at $225 to $300 a year; tires at $275 for a one-ton machine to $1,650 for a ten-ton truck; overhauling and general repairing at $300 to $550; depreciation at 15 percent; interest at 5 percent, and fire and liability insurance at $150 to $240 per annum. One of the electric commercial vehicle companies furnishes Establishing the general average operating costs for the three models which it makes. Fixed charges on the delivery wagon amount to $303 a year for interest and depreciation on non-weary parts; maintenance for maximum service to $389 a year, and garaging, including charging current to $108. This amounts to $800 a year, or $2.66 per working day, not including drivers' wages. At $15 a week, wages would bring the total daily cost to $5.16. On the same basis, the total cost of running the light truck is $5.63 a day and that of running the heavy truck $6.91 a day. Larger and heavier makes of electric trucks cost from $7 to $8 a day to operate. Contractors' Cost of Hauling- Blasted Rock. The following data on motor truck work hauling blasted rock are furnished by the Charles P. Boland Company, engineers and contractors of Troy, N. Y. The contract called for the excavation and removal of 23,000 cubic yards of rock. The rock was blasted and hauled in two 3-ton trucks. These were equipped with patent dumping bodies and were used continuously, day and night shifts. The excavated material was hauled in some cases a distance of one and a half miles. The records show that these trucks carried about twice the amount usually hauled in a vacuum dump wagon and made the trip to the dumping ground and return in just half the time required for a team to make it. Experience proved that it was necessary to keep the trucks continuously on the move in order to work them economically, and with this idea in mind, large steel bottom dump buckets were used in loading the trucks; thus no time was lost in loading, as several buckets were full at all. times and the operation of reloading the trucks took only the time required to hoist the buckets over the trucks. The actual loading operation required but a few minutes. In the hauling of materials from the freight house to the building site, the records show that hauling cement cost about 1 1/2 cents per bag, or 30 cents per ton. Eighty bags were carried on each trip and eight trips were required to unload a car containing 640 bags. Increased efficiency was obtained by having at least six laborers to do the loading, as little time is lost if the loading force is large enough. The average record of each car of cement from the freight house to the site of operations, a distance of about 1 1/2 miles, was as follows: 6 Laborers, 6 hrs. each day, at 16c $5.76 1 Chauffeur, 6 hrs. each day, at 25c $1.50 Fuel, oil, etc $55 Percentage of maintenance charge $1.00 Total $8.8.1 Referring to their experience on this work, the contractors write as follows: In the care of an automobile truck, our experience has taught us that it is economical to keep every part well lubricated at 41 Fig. 17. Fierce-Arrow 5-Ton Truck with Hydraulic Hoist. Fig. 17A. Fierce-Arrow 5-Ton Truck, High Level Tipping Body. 42 HANDBOOK OF CONSTRUCTION PLANT Fig. 18. Packard Dump Truck. Fig. 18A. Packard 5-Ton Dump Truck. AUTOMOBILES 43 Fig. 19. White 3-Ton Truck. Fig. 19A. White 5-Ton Truck. 44 HANDBOOK OF CONSTRUCTION PLANT Fig. 20A. Mack 7½-Ton Automatic Dump Truck. Fig. 20A. Saurer 6½-Ton Truck with Wood Hydraulic Hoist. AUTOMOBILES 45 Fig. 21. Peerless 5-Ton Rear Dump Truck. Fig. 22A. Kissel Kar 3½-Ton Truck with Hydraulic Hoist. 46 HANDBOOK OF CONSTRUCTION PLANT Fig. 22. Garford 5-Ton Dump Truck. Fig. 22A. Knox Tractor with Trailer. AUTOMOBILES All times. A cheap or an inferior grade of oil should not be used, as the carbon forming qualities of a cheap oil more than offset the saving in the price. Where more than one truck is in use at least one chauffeur should be employed who is a thoroughly practical man. This will enable one to have each truck carefully looked over each day and any disarrangement corrected before damage is done. We have had little or no trouble with these trucks. The main expense in connection with the maintenance of the trucks is the wear and tear on tires. We are now using a wire mesh tire made by the Diamond Rubber Company which seems to give us good service. The company referred to sells these tires on a guaranteed mileage basis, and if renewals are necessary before the mileage is completed, a replacement is made by them and an adjustment made on the basis of the mileage obtained. Owners' Reports on Costs of Motor Truck Operation. The following data on the cost of operating motor trucks are condensed from a paper by L. R. Button before the American Gas Institute: Electric Trucks. One company reporting five 1-ton trucks (all of one make) one and one-half years old, one %-ton truck, and one 2-ton truck, in use only a few months, furnishes the following operating costs. Total mileage of the seven cars, 39,507 miles: Cost. Total Per mile Battery maintenance $95,028 Chain and sprockets 146,58 Chassis repairs 54,09 Current 282,38  $0.098 Insurance $ 539.90 $0.014 Battery maintenance accrued 984.57 0.025 Tires depreciation accrued 199.08 0.005 Depreciation at 10 per cent 2,054.00 0.052 Interest at 8 per cent 1,739.40 0.044 Total cost $9,411.82 $0.238 The following figures are given on a 2-ton electric truck covering two years' service: Total Cost cost per mile Current at 2 % cts. per k-w h $ 253.88 $0.0275 Labor for maintenance 486.78 0.0528 Maintenance and repairs 1,130.04 Total expense $1,870.70 $0.2028 Miles traveled, 9,225. This truck is reported out of service for maintenance in the two years, 12 % per cent of the working hours. The same company reports the following summary of Expense on a 1,000-pound electric truck, covering a period of two and a half years' service — total mileage, 10,274. Total Cost cost per mile Interest on $1,668 at 6% $250.20 $0.0244 10% depreciation on the value of wagon 244.20 0.0237 Maintenance and depreciation of batteries 601.02 0.0586 Tires and repairs 210.00 0.0204 Wagon expense, repairs 145.12 0.0142 Miscellaneous charges 48.54 0.0047 Total expense $1,499.08 $0.1460 It will be noted that the owner of this vehicle suggests different depreciation values on various parts of an electric machine. He divides it as follows: First, depreciation on wagon; second, depreciation on tires; third, depreciation on batteries. These expenses are complete, because the expense is included up to the point where the truck has a new set of tires, and is in good condition except that the wagon needs painting. It also had a new battery installed during the past year. Valuable information (Table 17) on the operation of electric vehicles Can be obtained by consulting the Report of the Committee on Electric Vehicles, National Electric Light Association, June, 1911. TABLE 17— COST OF OPERATING 1,500-LB. AND 3,000-LB. CAPACITY DELIVERY WAGONS. -Average Cost- Fixed Charges and Per mile. General Expense month Total Cents Drivers' salary $65.00 $5,687.50 $9.0 Supervision 5.22 456.75 0.7 Garage rent 5.18 453.25 0.7 Wheel tax 2.67 233.62 0.4 Washing, oiling, etc 13.00 1,137.50 1.8 Interest at 5%, taxes at 1.5%, and insurance at 5% on total cost of wagon 14.58 1,275.65 2.0 Depreciation: Batteries, 66% per year on $255 14.17 1,239.87 2.0 Tires, 100% per year on $225.60 18.80 1,645.00 2.6 Balance of wagon, 10% per year 15.99 1,399.13 2.2 Total general expense and fixed charges. $154.61 $13,528.27 0.0078 3d Car. 15,651 Miles. 2,000 Yrs. Use, Total Cost cost per mile $154.60 $0.010 34.27 0.002 243.48 0.016 76.43 0.005 $352.74 $0.037 $404.71 $0.0332 $508.78 $0.033 One company reports the use by salesmen of three cars costing $750 each. Being low-priced cars and covering only from 500 to 800 miles per month, the depreciation was high. The amount charged for depreciation was the actual amount, because the cars were sold at the end of the year and the loss was known. The operating expense on the first car was 4.8 cents per mile; on the second, 10 cents per mile; on the third, 10 cents per mile. If these cars were used by only one salesman, it would indicate that the cost was unusually high. A well-known company in another line of business, having salesmen in various parts of the country, furnished fourteen of its men with runabout cars costing $1,000 each. The cars average four months' operation; mileage of car 3,830. Item of expense: Gasoline, oil and grease, repairs to motor, depreciation, 25 percent per annum. Total cost per mile, 14.9 cents. Gasoline Trucks, 1,000 Founds Capacity. Cost of operating five 1,000-pound trucks of a well-known make, costing $750 each, with large wheels and solid tires: Cost Mileage per mile Truck No. 12,000 0.0926 Truck No. 13,210 0.042 Truck No. 14 3,160 0.045 Truck No. 15 3,924 0.045 The cost of the above trucks includes gasoline, oil and grease, tire repairs. and sundries. The average is very uniform, except with car No. 1, the additional expense originating from a broken motor caused by an inexperienced driver learning to operate. The different companies operating these trucks all state that the depreciation cost is very high. In most cases, the truck can only be kept in use a few months or a year and traded in for a new one. At least 50 percent depreciation should be charged the first year. A practically similar experience was reported by a company with a truck of the same capacity and low cost, built by a different concern. One Ton Trucks. Three companies report on the use of 1-ton trucks of different makes. Company No. 1 reports on two 1-ton trucks; total mileage, 18,550; cost per mile, 10 cents. This includes gasoline, oil, tires and motor repairs. The opinion of the owner is that the depreciation is 33 1-3 percent per year. Company No. 2 reports on three 1-ton trucks. The report covers gasoline, oil, tires and repairs. The owner estimates depreciation 15 percent. Truck No. 1, 6,060 miles; cost per mile, 11 cents; truck No. 2, 6,300 miles; cost per mile, 10 cents; truck No. 3, 8,000 miles; cost per mile, 8.6 cents. Company No. 3 reports on the operation of one 1-ton truck. The expenses on 2,600 miles are as follows: Total Cost cost per mile Gasoline, at 11 cts. per gal...: $ 34.05 $0013 Oil, at 50 cts. per gallon...: $ Gal C 8.45 0.003 Tires (accrued) 48.00 0018 Repairs, none. Total $ 90.50 $0.034 The item of tires mentioned above was owing to the rear tires being too light. They were removed and 1 inch heavier solid tires installed, at the above cost. The motor is of the two-cycle type. One and One-half Ton Trucks. Only one company has reported on a truck of this capacity and similar make. The report covers a total of 11,150 miles and the truck was in use fourteen months. Total Cost cost per mile Gasoline, at 15 cts., 7 mill, per gal $ 236.70 $0.0212 Oil, at 35 cts. per gal 35.00 0.0031 Tires and repairs 150.00 0.0134 35.10 0.0031 Total expense $ 456.80 $0.0408 The owner believes 12½ per cent depreciation should be charged on this truck. Its makers have reports from the owners of hundreds of these cars and claim the operating costs to average 8 cents per mile, made up as follows: Five per cent interest on investment; depreciation, 25 per cent; gasoline, oil, tires, motor repairs and maintenance, 70 per cent. Two Ton Trucks. From the reports received only three companies are using the same make. One of the three furnishes detailed costs of operation, which report is very complete. Truck was owned fourteen months, or 352 working days; days in use, 227; days idle for repairs, 75, or 21 per cent. The owner reports that, although this car has been On the market for several years, an unusual amount of time was lost because of poor service rendered by the manufacturers and agent, owing to delays in obtaining repair parts. When parts were received, they either did not fit the machine or were not perfect. Time lost was due as follows, in days: To springs, 5; to tires and wheels, 13; to motor, 33; to transmission, 15; to radiator, 9. The mileage was 11,300; gallons gasoline used, 2,250, or 5 miles per gallon; miles traveled daily, 41. A summary of the operating expense of this truck is shown as follows: AUTOMOBILES Total Cost cost per mile Gasoline $ 298.23 $0.0265 Oil 100.41 0.0089 Tires and repairs 432.98 0.0384 Car repair and sundries 370.22 0.0328 Labor, cleaning, etc 514.27 0.0456 Total $1,716.00 $0.1522 Standing Expense. 