THE RETURN CIRCUIT. 49 
The electrically welded joint when carefully made is 
strong and reliable and of almost infinitely small resistance. 
The contact is non-corrodible, of great surface and so in- 
timate as not sensibly to increase the resistance of the 
track. It is as far superior to a bond contact as the latter 
is to the contacts made through rusty fishplates. A track 
so excellent mechanically and electrically needs no com- 
riendation here, more than to reiterate the value of a com- 
plete and permanent connection between rails. 
The ‘¢ cast welded’’ joint hasnow come into very con- 
siderable use. Mechanically it is superior, but electrically 
it is scarcely the equivalent of the welded joint. Between 
these two rival continuous rail processes it is difficult to 
choose. Certainly both afford at once the solution for the 
joint alignment and the bonding difficulties. Both are 
likely to come into very extensive use in large city roads 
where the electrolytic troubles are usually most noticeable, 
although small roads are not exempt from them. Ehe ze- 
sistance of a cast-welded joint, although not uniformly 
negligible, is about the same as that of the very best 
bonded joints and is more permanent. 
It has often been urged that a double trolley system 
should be employed to avert danger of electrolytic action. 
Experience has shown that the double trolley is not likely 
to become a favorite with street railway men. 1t can be 
worked stccessfully with proper care, but the mechanical 
difficulties in the way of installing and keeping up the 
overhead system of frogs, crossings and the like are some- 
what formidable. On a straightaway road with no 
branches or few the task is easier, but for the purpose in 
hand such roads are not the ones requiring the most serious 
consideration. ‘The troubles belong especially to compli- 
cated city systems in which the difficulties of a double 
trolley system are something terrific. Inasmuch as every 
electric railway company has to pay for what can be made 
a magnificent return circuit, it seems totally needless to 
throw away the rails and operate a double metallic circuit 
overhead. Especially is this true in view of the fact, that