It seems that the 70 series will be around for awhile, especially as right now EMD appears to be ahead of GE in Tier 4 development. An SD70AC"something" designation seems logical..
Keep in mind that the 70 series was supposed to have been superceded in EMD's Catalog by the SD89MAC (SD90 development with a 4500 HP 12-265H engine) but the problems with the 265H scuttled that..
Can someone enlighten me on the criteria for a new locomotive model number? Does it depend strictly on the engine type? The SD70ACe and the original SD70 seem to be radically different locomotives in both appearance and features. The EMD model number designations make no sense to me, as there was already an SD90 (which is mostly off the rails today as I understand). Or are they supposed to make no sense?