Caption: CN container train 148 has ES44ac CN 2860 in the lead. It's the second unit that is interesting - EMDX 1605, painted in Union Pacific colours, is one of EMD's Tier 4 demonstrator units. Hood-side lettering beneath ELECTRO-MOTIVE reads THE NEXT GENERATION OF PROGRESS ## SD70ACe-T4

While EMD has labelled the locomotive as a member of the SD70 family, the prime mover is very different. Apparently the 2-stroke EMD 16-710 diesel engine, as used in other SD70's, could not be adapted into a practical Tier 4 compliant engine.
Instead the locomotive is powered by a 12-1010J 4-stroke diesel engine rated at 4600 HP, developed from the 16 cylinder 265H 4-stroke diesel that was the intended power for EMD's SD90MAC-H.
Web sources indicate that UP ordered 88 SD70ACe-T4 and has a number of them in service, while Norfolk Southern had 10 on order as of August 2018.

There are 3 trains on the 4 tracks in this picture: Track 3 is unoccupied, CN 148 is on Track 2, CN 422 is on track 1, and CN 421 is on the Aldershot Yard west end lead.