I'll try to answer what I think you're asking:

BC Rail did have an electric operation, the Tumbler Ridge branch, which existed exclusively to move coal from mines in that region of Northeastern BC to the mainline. From there the coal traffic was handled by conventional diesel-electric power. Google "Tumbler Ridge electrification" or something like that and you'll get lots more info. The Tumbler Ridge branch is nowhere near the mainline through Pemberton, which is a little north of Whistler on the original PGE mainline between Squamish (and North Vancouver) and Lillooet.

BC Rail used both manned helpers AND remote-control power. The "Pemberton Push" manned helpers boosted trains (southbounds, mostly) over a couple of significant grades near the namesake town of Pemberton. Remote control operations were not confined to that area, but it's been so long, my familiarity with their RC operations has really faded. In general they resembled what we'd now call "distributed power" operation.

BCR was a heavy-duty mainline railroad but it also had lots of rather sharp curves and a pretty hilly profile, so they were fairly early adopters of RC operations and stuck with it right until CN happened.

There's lots of info out there on the WWW as well as some great books written about BCR if you're so inclined. "Northern Light" by Dale Sanders is an absolute stunner and covers more-recent operations, the RWB era and the last decade before CN. JF Garden's masterpiece "British Columbia Railway" essentially covers the whole history of the railroad, but the photographic emphasis is one to two decades before Sanders' book. Another title to look for is "Route of the Caribou" by Afolf Hungry Wolf. Brian Echlepp (sp?) authored at least one BCR book, maybe more? And there are others I'm no doubt forgetting. Oh, and how could I forget, CTC Board magazine had a few awesome issues dedicated to BCR, around the 1985-1990 timeframe.