After reviewing the dizzying list of capital projects that Metra is considering, my guess is that the agency will first tackle those projects which require less time and money to complete before it takes on those that require more to finalize. Besides, I don't see the agency retiring any locomotives anytime soon, but if it does, the only ones I can think of that will be replaced are the F40PH-2s which were never sent to rebuild.
According to Metra, it is less expensive to buy new locomotives meeting Tier III emission standards than rebuilding the current locomotives to meet those standards. Wasn't this done during the last rebuild program? If Metra can send 49 F40PH-2s to Progress Rail for rebuild, thus giving them a life extension of at least 10 years, then how come the agency cannot send the remaining 34 to PR or another manufacturer for rebuild? And if Metra does decide to buy new locomotives, what model or manufacturer are they currently considering? EMD I hope.
Question everything, research everything, never stop learning. Knowledge is limitless!