How is it with mechanical systems?  The land is one of the minor considerations, the last thing considered.  Let us look at some figures.  From careful examination of many engine plants, considering the ratio between a certain number of horses with their necessary adjuncts and a steam plant of numerically equal power, I find it stands as 1 to 30.  That is, a steam plant complete of 30 horse power capacity would need only one thirtieth the floor space of thirty horses.  With larger powers this ratio is still greater, and from one estimate I found that it stood as 1 to 108, i.e., for horses I should have to have 108 times more floor space than for an equal number of mechanical horse power.  It must be remembered also that the mechanical horse power is 50 per cent. greater than the best animal horsepower.

From one maker, taking the engine alone, I found that a rated 100 horse power engine, guaranteed in every particular, would have ample room in the stall for one horse in the average stable.  Another instance showed that I could get a steam plant complete, engine, boiler, etc., of 50 horse power, in a space 5 by 6 feet, which is smaller than the average stall.  Here is shown the enormous saving in land purchase.

For car room a building several stories high would answer perfectly, since quick-hoisting elevators could be put in and the tracks on each floor have wire connections with the dynamos, so that the cars 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.