BY MONTAGUE RHYS JONES, C.E. 79 



composed of lead, weighing altogether about 3,500 lbs. in an 

 ordinary street car, thereby reducing the electrical efficiency 

 by nearly 60 per cent. These cells, stored with power, have 

 to be always carried about, whether over heavy or light 

 grades, and if the car has to surmount any grade over 5 per 

 cent., which is common in streets, the capacity and discharge 

 rate is so limited that it is with only great difficulty and 

 serious injury to the mechanical parts that they can be 

 negotiated, and the chemical energy of the cells instead of 

 supplying current developes heat and buckles the cell plates. 

 Platinum or gold might withstand this constant molecular 

 activity ; but then, again, it does not do away with the dead 

 weight, to say nothing of exjDense ; but I believe gelatinous 

 cells are spoken of as being highly probable in place of the 

 lead cells. Last January I was asked to value the assets of 

 the Eaglehawk Electrical Tramway Company, which was 

 operated on the storage system for about three months or 

 more, and which proved an entire failure. Its cost amounted 

 to .£40,000, and the debris was worth about £5,000. It 

 could have been nothing but ignorance that suggested the 

 storage system for Sandhurst, as the street conditions were 

 entirely unfavourable for such. It is indeed difficult to 

 speculate what the ultimate destiny of the storage car will be, 

 but if improved up to present commercial requirements the 

 most perfect ideal of street transit will have been accom- 

 plished. 



The underground system, in point of construction, is very 

 much like the cable system, so far as relates to the conduit for 

 carrying the conductor, and the chief objections to it are cost 

 of construction. The conduit in a busy thoroughfare would 

 probably have to be excavated without the use of explosives, 

 at a great cost ; and without a large wetted perimeter is 

 allowed for during heavy rains the channel would be flooded, 

 and the water and street debris would come in contact with 

 the conductor, which cannot be fully insulated owing to con- 

 tact with the trailer, which is suspended from the car, and 

 from which the motor takes its supply of current. The 

 efficiency is entirely destroyed by short circuits and leakage. 

 There are many other mechanical difficulties to be overcome, 

 and one of the great drawbacks which militate against its 

 success is the large amount of ironwork on the surface of the 

 street, together with difficulties of switching and cost of 

 maintenance. 



We now come to that system which has been most success- 

 fully operated, commercially and practically, throughout the 

 world, and whose adherents and supporters are growing 

 yearly, namely, the " overhead system." Overhead conductors 

 consist of two elements, one having a metallic circuit of two 



