Jim Betz wrote
For instance - where would coal for such purposes have been shipped
from - going to locations in Central or Northern California? I know
there was coal in Utah that was being shipped to Southern California.
Coal burned in central and northern California came from Utah & Colorado
(and maybe Wyoming too) most commonly via SP's route over Donner Pass.
Rio Grande coal gondolas and coal hoppers were a common sight on the SP.
The Western Pacific also moved some of this coal. It's possible to move
the coal via the Union Pacific (LA&SL) first, and then via ATSF or SP over
Tehachapi, but that's a much longer haul in most cases. The Santa Fe and SP
also served coal mines in New Mexico, so that's another possible source.
But again, a longer haul.
what 'influence' did the railroad that the industry was on have on the
source of the coal
This is where the tariffs come in. As "common carriers" railroads could not
refuse to move coal from here to there, but the tariff might be prohibitive
compared to other sources and tariffs. So the "influence" was indirect. If
the mine felt that the tariff was unfair, they could appeal to the ICC. And
shippers did that more or less constantly and relentlessly.