"COLTON-HIGHLAND AVE. LINE: The through-routing of the Colton local line and the North D St. line resulted in this line. Power for this line was supplied at 600VDC from Substations 24 at San Bernardino (most likely the sub where the INS building now sits -SDJ) and Substation 25 at Arrowhead. After abandonment, PE used cars 1036 and later 1362 to make the franchise runs; for a short time a 100 class car was used but so many patronized it in preference to the bus, that the 1036 was put back on.
At Mt. Vernon and Rialto avenues, this line crossed PE's main line to Los Angeles. A somewhat elaborate overhead construction was required to keep the 600VDC trolley wire and the 1200VDC trolley seperate. Needless to say, the gaps came in the 600VDC wire. From 1 June 1931 to 25 Nov 1931, this line furnished connecting serivce to Arrowhead line; latter line was then operated as a shuttle from Highland Ave. to Crusher (1.92 miles) with one round trip to Arrowhead Springs."

From page 83.