I believe the remnant of the La Cadena was the line that stubbed off toward Fairmont Park and it
was still there in 1963 when I was attending UCR. There was still trackage serving the freight house off the Corona line at what I think was called Arlington at the time. The Arrowhead Springs
line was still in during 1963 and but was pulled up some time shortly after that. The Norton or
San Bernardino Ave line was indeed still worked in the 60's serving two packing houses and ending
at Sunkist. There was plenty of leftover trolley hardware still left so it at least appeared to
have been electrified and since this was the line to Redlands I would presume to be so though your
question of whether it was PE or SP is a good one. I always assumed the Rialto street trackage
had been electrified at some point though the line through Norton didn't appear to be so.