Electrification vs. Diesel Costs

With the price of fuel spiking (and now coming back down), for larger systems like Metra and MBTA, the cost of fuel has to be one of the largest expenses. When does it become cost effective to electrify their most popular lines? Or in the case of the T, when do you buy electric power, and draw off Amtrak on the NEC?

I dont know, but I can name off a few metra lines here in chicago that SHould be electrified just because they have zero freight traffic or at least no double-stacks..
the Union Pacific North line to Kenosha has almost no freight traffic south of waukegan.. this line would be a good candidate for electrification. the other obvious candidate would be the Rock Island. Forget about MU's they are costlier to maintain, get electric locomotives like New Jersey, new or used would be fine.
for some reason I highly doubt that any other south shore extensions will be electrified.

Despite being costlier to maintain MU's have advantages such as train length flexibility and acceleration. Electrified short run commuter lines, with their frequent stations, for the most part have MU's, locomotive push-pull with coaches is not as prevalent. I doubt anybody making the tremendous investment to put up wires, maybe $billion, would find the relatively small cost difference MU vs locomotive, maybe $100 million vs $50million, worthwhile.