It is my understanding that SP did, in fact assess electrifying the Donner Pass, in the early to mid 1900's. Smoke incidents in the snow sheds and tunnels, fires, and the steep grades spoke to electrification, as an answer to those problems. Cab forwards and a relatively cost effective firefighting system left those plans unused.

In about 1968-69 SP embarked on a study of rail electrification between Los Angeles and El Paso. These plans were discarded due to cheap fuel prices and the SD-40 and SD-45 T2's which were so darn cheap to operate. Double tracking, which almost certainly would have been required on the major grades with electrification, also was postponed nearly 40 years. SP, meanwhile, took its railroad earnings and invested in real estate, banknote printers, and Sprint, while offering increasingly un-competitive rail service to their "captive" customer base. This brilliant business "strategy" allowed the SP to lose much of its customer base and to deteriorate to the point of actual physical plant meltdown by the time UP acquired it.

Diesel costs now has a number of foreign and domestic investment firms looking at financing and constructing railroad electrification projects in the US. Time will tell?