First, I did NOT claim "the 4014 could operate anywhere on the UP". I stated "No problem operating on any UP mainlines." I'm sure there are many non-mainline tracks the UP would not run the 4014.
This is MY opinion: Union Pacific has been in business for a long time. They built and rebuilt their mainlines probably several times over. And I'm sure each time, they've made sure to leave plenty of room between tracks for WHATEVER is run on their tracks, be it a big locomotive or specialty rolling stock. I stand by my original statement.

It sounds like there are TWO potential concerns with the 4014:
1) Swing-out clearance.
2) The ability of a 4-8-8-4 locomotive to negotiate a curve radius. (MY opinion: if a locomotive with a single set of 8 drivers could make a curve, a locomotive with TWO sets of 8 drivers could make the curve, due to articulation.