As regards the steam motors, the following were the results from the time of lighting the fires:
The Rowan - In 34 minutes 3 atmospheres. " 36 " 4 " At this pressure the vehicle could move - In 40 minutes 8 atmospheres. The Wilkinson - In 35 minutes 2 atmospheres. " 40 " 4 " " 44 " 6 " " 47 " 8 "
The Krauss machine required two hours to give 6 atmospheres, which was the lowest pressure at which it could be worked.
The results under No. 17, viz., the fewest interruptions to the daily service, class the motors in the following order: Krauss, electric, Rowan, Wilkinson, compressed air. The chief cause of injury to the compressed air motor arose from the carelessness of the drivers, who allowed the steam boiler to be burnt out. Unfortunately, these drivers were new to the work.
Under the letter C are classed considerations of economy in the consumption of materials used for generating the power necessary for working.
19. Minimum consumption of fuel (either coke or coal), in proportion to the number of kilometers run, and to the number of places, assuming for the seats a width of at least sixteen inches for each person seated.
It must be borne in mind that the conditions of the competition required that a second car should be periodically drawn by the motor, and that the calculations which follow include the total number of miles run, the total amount of fuel, etc., consumed, and the total number of passengers which could be conveyed by each motor, during the total time that the experiments were being carried on.
TABLE II. Total Description of motor. number of Total No. of lb. train miles Consumption per run. of fuel. train mile. lb. Electric. 2,358.9 14 786 6.16 Rowan. 2,616.9 14,498 5.42 Wilkinson. 2,473.3 22,000 8.82 Krauss. 2,457.8 22,726 9.10 Compressed air. 2,259.1 90,420 39.48 TABLE III. No. of places No. of lb. of Description of motor. indicated on fuel consumed the cars, per Consumption per places mile run. of fuel. indicated per mile run. lb. Electric 80,203.5 14,786 0.18 Rowan 148,399.6 14,498 0.09 Wilkinson 119,085.1 22,000 0.18 Krauss 108,983.9 22,726 0.20 Compressed air 128,189.3 90,420 0.69 TABLE IV. Description of motor. No. of seats per No, of lb. of mile run. Consumption fuel consumed of fuel. per seat per mile run. lb. Electric 61,591.2 14,786 0.23 Rowan 135,928.8 14,498 0.10 Wilkinson 93,965.6 22,000 0.23 Krauss 86,039.9 22,726 0.25 Compressed air 132,732.7 90,420 0.66
As regards the figures in these tables, it is to be observed that the consumption of fuel for the electric car is, to a certain extent, an estimate; because the engine which furnished the electricity to the motor also supplied electricity for electric lights, as well as for an experimental electric motor which was running on the lines of tramway, but was not brought into competition.
20. Minimum consumption of oil, of grease, tallow, etc. (the same conditions as in No. 19).
TABLE V. Total Consumption Total consumption of oil, tallow, Description of number of of etc., motor. miles run. oil, tallow, per train mile etc. run. lb. Electric 2,358.9 99.0 0.038 Rowan, steam 2,616.9 106.7 0.038 Krauss, steam 2,457.8 188.5 0.073 Wilkinson, steam 2,473.3 255.4 0.101 Compressed air 2,259.1 585.2 0.255
In addition to these considerations, it was thought useful to investigate the quantity of water consumed in the case of those engines which used steam. The experiments made on this point showed as the consumption of water:
Gallons per mile. Rowan 0.75 Compressed air 1.06 Wilkinson 5.89 Krauss 6.52
Thus, owing to the large proportion of water returned from the condenser to the tanks, the Rowan actually used less water than the compressed air engine.
The general conclusion to which these experiments bring us is that, undoubtedly, if it could certainly be relied upon, the electric car would be the preferable form of tramway motor in towns, because it is simply a self-contained ordinary tram-car, and in a town the service requires a number of separate cars, occupying as small a space each as is compatible with accommodating the passengers, and which follow each other at rapid intervals.
But the practicability and the economy of a system of electric tram-cars has yet to be proved; for the experiments at Antwerp, while they show the perfection of the electric car as a means of conveyance, have not yet finally determined all the questions which arise in the consideration of the subject. For instance, with regard to economy, the engine employed to generate the electricity was not in thoroughly good order, and from its being used to do other work than charging the accumulators of the tram-car, the consumption of fuel had to be to some extent estimated. In the next place, the durability of the accumulators is still to be ascertained; upon this much of the economy would depend. And in addition to this question, there is also that of the durability of parts of the machinery if exposed to dust and mud.
After the electric car, there is no question but that at the Antwerp Exhibition the most taking of the tramway motors was the Rowan, which was very economical in fuel, quite free from the appearance of steam, and very convenient and manageable.
The economy of the Rowan motor arises in a large degree from the extent of its condensing power, by means of which a considerable supply of warm water is constantly supplied for use in the boiler, and consequently the quantity of water which has to be carried is lessened, and the fuel is economized.
Independently, however, of its convenience as a motor for tramways in towns, the Rowan machine has been adapted on the Continent to the conveyance of goods as well as passenger traffic on light branch railways, and fitted to pass over curves of 50 feet radius, and up gradients of 1:10.
In England, with our depressed trade and agriculture, there is a great want in many parts of the country of a cheap means of conveyance from the railway stations into the surrounding districts; such a means of conveyance might be afforded by light railways along or near the road-side, the cost of which would be comparatively small, provided that the expensive methods of construction, of signaling, and of working which have been required for main lines, and which are perfectly unnecessary for such light railways, were dispensed with.
It is certain that this question will acquire prominence as soon as a system of local government has been adopted, in which the wants of the several communities have full opportunity of asserting themselves, and in which each local authority shall have power to decide on those measures which are essential to the development of the resources of its own district, without interference from a centralized bureaucracy.