3d. Equipment at station and rolling stock.
The rolling stock would be in each case approximately the same. Consisting of cars of equal seating capacity, the difference of cost would be the necessary attachments for the mechanical systems.
I believe, however, that the mechanical system is bound to work material changes in car construction, in fact it is almost imperative. In all probability a car with 15 to 20 per cent. greater seating capacity than the horse car can be constructed on a different plan for the price given for the electric car. This price, it must be noted, is the one for attachment of motor to the present horse car. The horse cars produced to-day are most carefully planned, thoroughly built, and admirably adapted to their service, but the inexorable law of progress decrees their extinction, for something better.
Motive power. To represent clearly the costs, etc., of the three systems under this head, let us assume a road. Take, if you please, a double line 6 miles long, and operating 24 cars with speed of 6 miles an hour, and running 20 hours out of 24. This would call for 48 horses on the track and 192 horses in the stables, or a total of 240 horses; at $160, counting harness, etc., this would cost $38,400.
With electricity we will proceed as follows: The weight of car with 30 passengers and motor attachments would be about 9,000 lb. It is easily calculated that to propel the same at the specified rate on a level would take about 1.75 horse power, a total of 42 horse power. To make allowances for grades we can calculate that, if the entire road was one gradient of three per cent., each car would take about 6.4 horse power, or since only 12 are going up, a total of 76.8 horse power. It will be fair now to take the average of these two, or 59.4 horse power for an average road. Allowing 35 per cent. loss from engine to work done in actually propelling car, we would have to have 91.3 horse power. Allowing a good safety factor, it would be well to put in a 150 horse power plant. This would cost complete $7,000; necessary dynamos, $3,500. Among these figures should be counted cost of conductor of sufficient size to allow of but three per cent. in energy to overcome its resistance. This I have calculated using a potential of 600 volts; and find that the total cost of six miles copper conductor is $16,000 with above conditions.
The total cost is now seen to be $26,500.
As to cables, since the recovery of energy available for tractive purposes is but 35 percent., then the engine of 169 horse power represents what must be had. Allowing a generous factor of safety, let us say that a 250 is all sufficient. This would cost complete and erected about $12,000. The cable would cost $15.000, and gears, etc., $8,000, making a total of $35,000.
The ratio of the three systems stands: Electricity, 1; cable, 1.09; horse, 1.45.
4th. Construction of tramway.
Figures upon this point must necessarily be either averages or approximations. The nature of the locality socially, naturally, and we grieve to say it, politically, has a strong influence upon its construction. Estimating on single track only, a horse road would cost as an average $9,000 per mile. With electricity we have several methods we can avail ourselves of: Surface, costing about $10,000; overhead double conductor, $15.696; underground, $23,500.
With cable but one method, the underground, is possible. This cost is variously estimated at from $30,000 to $110,000 per mile; however, the latter figure is excessive. A fair average would be $35,000.
The ratio of constructions could be fairly placed as follows, putting electricity as 1, by taking the average of the three methods at $16,732: Horse road, 0.53; cable, 2.09.
Unquestionably a great majority of roads of the past have not been constructions of engineering, and of all places requiring care, skill, and engineering, the street roads are the places.
5th. Cost of operation.
A fair figure for cost of one horse for one year is $220.
For electricity, allowing 35 per cent. loss in transmission, etc., 1.54 horsepower would be the work done by engine to get 1 horse power on the track. There are to-day plenty of steam plants producing 1 horse power for work at from $30 to $50 per annum. Take the average, $40. With electricity then $65 would well represent the price of producing 1.54 horsepower.
With cable these figures would hold true, but more work is required. A greater loss is entailed. Since but 32 per cent. is recovered, the figure for 1 horse power on the track would be 2.86 horse power. At the above rates this would be $110 per horse power per year.
Our ratio here is: Electricity, 1; cables, 1.71; horses, 3.38.
This is by no means the whole of the story, for just here must we compute the depreciation and hence repairs due to time. Let us take the road figured on heretofore, and make three tables.
In the following I have under each system taken the estimated costs, allowed a fair per cent. for depreciation, summed up and obtained the ratios.
Any figure then like interest, etc., which would not affect ratios, I have omitted.
|Conductors, 1 per cent.||$160.00|
|Engine and dynamos, 5 per cent.||525.00|
|Cars, 10 per cent.||5,280.00|
|Roadway, 10 per cent.||2,007.00|
|Horses and appurtenances, 20 per cent.||$7,780.00|
|Cars, 10 per cent.||2,880.00|
|Roadway, etc., 10 per cent.||3,500.00|
|Cable, 50 per cent.||$7,500.00|
|Engine and boiler, etc., 5 per cent.||1,000.00|
|Cars, 10 per cent.||4,320.00|
|Roadway, 10 per cent.||3,500.00|
These totals put in ratio are as follows: Electricity, 1; cable, 2.04; and horses, 1.47.
Placing all the ratios obtained in a table, we have the following:
|Construction of tramway.||1||0.53||2.09|
|Motors, cars, etc.||1||1.63||1.21|
Now this table must stand by itself for what it represents, and no more. It will be noted that I have not introduced the subject of men. This would unquestionably show favorably for both electricity and cable. Again, note, please, that this table does not represent your profits exactly as per ratios. I have to get them operated the same number of cars and under the same headway. Now with either electricity or cable a higher rate of speed can be maintained with but a very small proportionate increase of cost. This means quicker time, more trips, and greater receipts.
Evidently, as a financial investment, even if cost of maintenance and operating is greater, the cable is to be preferred to horses.
How is it with electricity? The ratios of expenses, etc., stand for themselves, the law of speed is far simpler than with cable, bringing even greater receipts, and again in practice the saving of coal in proportion to work done on track day or night is immensely more economical than with the cable. This point will be touched upon later.
6th. Individual characteristics and advantages.
Under this head a few of the salient features of each system will be mentioned. As the possibilities and limitations of the horse railroad system are, however, so well known, it is needless to go over them. I therefore will confine myself to the electric and cable systems.
With electricity single track lines, crooked streets, all descriptions of turnouts, crossings, branches, etc., are as easy to construct and operate as with horses. With the cable system they are either impossible or enormously expensive.
With electricity the line is not a unit, so that the complete stoppage of the whole line is absolutely impossible. With cable it is a unit and it is possible.
With electricity the life of the conductor is infinite; with cable, two years.
With electricity, and the improvements now being made in traction wheels, etc., the heaviest grades are as easily surmounted as with the cable; although it is true that for grades exceptional in character, such as 20 per cent. grades or over, I should be willing to give the contract to cable.
With electricity any speed can be attained by the individual cars. They are absolutely independent. Lost time can be made up, etc. With cable the cars are dependent upon speed of cable. Lost time cannot be made up except on down grades.
With electricity work done by engine is synchronous with work done on the track at any time of the day or night, with the loss of 35 per cent. due to the conversions in each case. In other words, for every horse power of useful work done on track the engine does 1.54 horse power. This ratio is constant. It makes no difference whether 1 or 100 horse power of work is necessary on the track, the engine has but to do 35 per cent. in excess.
With cable, if 1 horse power of work is all that is required on the track, the engine may be doing 25 horse power to get that amount there through the gears and cable. With heavier loads this is somewhat diminished, but about the very best figure that can be put forth is but 35 per cent. recovery, with 65 per cent. loss - the exact converse of electricity under heavy loads. - Street Railway Journal.