Scientific American Supplement, No. 611, September 17, 1887 | Page 6

could be
run across the floor to where you please, facilitating storage and
dispensing with handling. This would not be possible with the cable.
Comparing electricity and cable on this point, all things favor the
former clearly and beyond all question. Furthermore, if locality so
favored, the subject of land purchase for electricity could be tabooed
entirely, since distance can be so readily overcome. Way out in the
suburbs or back in the country by the side of some waterfall, your
station might be, while the current is sent to the great city over heavy
conductors. Here land rent or tax would be at the minimum. With
horses or cable plainly proximity must be had. It is estimated that the
land occupied by the Madison Avenue line of New York City is worth

the cost of 40 miles of ordinary double track.
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.
A first class 16 foot horse car costs $1,200; A first class 16 foot cable
car costs about $1,800; and A first class 16 foot electric car costs about
$2,200. Rates: Electricity, 1; horse, 0.54; cable, 0.81.
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