. Electric railway journal . th cases thefeeders themselves were insulated from the tracks be-tween the point at which they were tied into the tracksand the busbar, but since the feeders were at the samepotential as the tracks at both ends, the potential gradi-ents on the feeders were, of course, the same as the potential gradients of the tracks which they paralleled,and hence electrical conditions were the same as theywould have been if the feeders had been substantiallyuninsulated and the relative electrolysis conditions andcosts were identical. The station selected for this experimental inv
. Electric railway journal . th cases thefeeders themselves were insulated from the tracks be-tween the point at which they were tied into the tracksand the busbar, but since the feeders were at the samepotential as the tracks at both ends, the potential gradi-ents on the feeders were, of course, the same as the potential gradients of the tracks which they paralleled,and hence electrical conditions were the same as theywould have been if the feeders had been substantiallyuninsulated and the relative electrolysis conditions andcosts were identical. The station selected for this experimental investiga-tion was the new Ann Avenue substation located at thecorner of Mississippi and Ann Avenues. The ratedcapacity of this station is 4000 kw at the present time,and the peak load (average for one hour) was at thetime the tests were made about 7540 amp. The aver-age load for twenty-four hours was 3500 amp, giving aload factor of about 46 per cent. It will therefore beseen that conditions at this station as regards size and. Electric Ry. Journal Fig. 2—Electrolysis Test—Final Arrangement with Insu-lated Negative Feeders character of the load are fairly representative of aver-age conditions in a moderate-sized city substation. Thetrack network in the district fed by the station is shownin Figs. 1 and 2. These show that only one single trackpasses immediately by the station and another singletrack passes along the street one block to the east. Thisis, therefore, an unfavorable location in respect to re-turning the current to the station, because the cross-section of rails approaching the station is unusuallysmall. On this account a relatively large amount of cop-per would have had to be installed whether the insulatedor uninsulated system was used, and therefore the costper kilowatt capacity of returning current to this sta-tion would be expected to be considerably higher thanthe average. This fact makes the test of the system amore severe one from the economy standpoint, al
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