I'm guessing you're referring to this?
http://chicago.cbslocal.com/2011/01/19/ ... tra-lines/
With all the discussion about diesel soot and other air pollution at downtown Metra terminals and aboard commuter trains, RTA executive director Joe Costello says the idea of electrification has come up.
“No one’s putting a proposal forward, but it has cropped up with fumes in the news, and it’s come up at public hearings over the years,” Costello said.
That's the key piece of information right there. Electrification was brought up as a possibility, but not a formally proposed option, for a solution to the whole Metra soot fiasco
uncovered by the Chicago Tribune.
The ultimate solution ended up being to just install high-efficiency air filters
. So the immediate reasoning for electrification has been knocked out with this development.
However, with the operational cost reductions, the overall reduced air pollution (not just inside the cars), the higher energy efficiency, and better acceleration, Metra should still be considering electrification. But that's not possible with the current political climate -- short term savings on neglecting capital projects trump long term operational savings.