A-2 is probably pretty much at capacity at rush hours. But non-rush hours are a different story with a base of six scheduled trains (hourly each way on the MD-N, MD-W, and UP-W) plus a few yard moves, Amtrak, and NCS. But considering how efficient they are at moving trains through A-2 (not atypical to see three MD side moves happening at once), I think CUS capacity is the more limiting factor at rush hours leading to the conclusion awhile back in this thread that this can't go in the peak of rush hour. At 5pm, there is not a spare track to be had at CUS-N (assuming you have to keep 19 open for whenever the Empire Builder decides to make an appearance). All moves are tightly choreographed with some tracks only sitting empty for a minute or two before the next arrival. While Metra has a workable "emergency" plan that lets them reduce the six primary tracks (5-15) to five should a track be OOS, it brings things to the point of no flexibility at all and a further problem makes the rush hour go south (among the bizarre things I've seen happen when a problem comes up have been Hiawatha on a Metra track (9), Metra on an Amtrak track (I've arrived and departed from 19 multiple times), and I've even seen 21 used for a Metra train once (no platform north of the concourse but can load adjacent to the concourse and in the run-through area leading to 28).
Larry
Reno, NV (yes, I've moved)
ex-N&W Sandusky, Ohio