When I first showed up and signed in at the old wooden coach sitting on the ground where you signed in at the 1879 round house firing on Beaumont helpers, they mostly used GP9's, sets of two, for manifest trains, cut in behind the caboose as helpers. These were usually cut in at Myoma.

For the 10,000 ton ore and the beets you had a set of at least 4, or preferably 5, GP9's which were cut in as swing helpers (2/3's of the way back), which were usually cut in at the crossover at Thousand Palms. You pushed the train up the hill, and provided dynamic braking to control the descent into Loma Linda, where you cut out the swing helpers or rear helpers on manifest trains.

The ore and the beets also had rear helpers, usually a minimum of 3 or 4 units, to help start the train, because too much power on the head end would suck a knuckle, or worse, a drawbar on a train that heavy using only the often 4-5 head end units. Once, we even pull a 100 ton beet gondola in two, when the center sill separated under such stress, on the "hill", and the beets rotted and stank all summer long at the Whitewater bridges, where they pushed it "over the side".

Up the hill slow (so slow you can drop off, catch a rear unit and fix a low oil button) and down the hill slow, was my experience, though, with heavy tonnage trains.

The beets and ore were often restricted to 20 mph (25 for the ore, if you had sufficient dynamic braking)and sometimes requiring retainers on the beets. As many as two beets and two ore trains a day ran during the summer, in between expedited Blue Streaks, Gold Streaks, and "hot" APW's with "shut down" auto parts cars for South Gate and Gemco.

So a lot of choo-choo's were required for a 10,00 ton train, on Beaumont's 2.5%+ ruling grades back in the "olden days". Today, distributed power, higher horsepower, and higher adhesion mean fewer more powerful loco's on most heavier trains.