As far as this as an ADA issue is concerned, the law doesn't require access at every entrance, just access at at least one entrance. If there are elevators on the other end of the station, and a level ADA-compliant path from that end of the station to the gates, the station is fine under ADA. If you're concerned about hauling your bags up escalators, perhaps you should use the other entrance to the station?
At Penn Station in NYC, it can be confusing and a bit of a hike to find the other entrances. NYP has, what?, at least 5 entrances spread around the 2 city blocks it takes up. There are also entrances to Madison Square Garden located above NYP that complicate finding the best entrances from the outside to the Amtrak, LIRR, and NJ Transit areas. With 2 levels, multiple internal corridors, multiple access corridors to 2 subway lines, and over 400,000 people getting on/off Amtrak, LIRR, NJ Transit trains on a normal weekday, NYP may be in a class of complexity all by itself in the US as far as train stations are concerned. When I started taking Amtrak to NYP on a semi-regular basis a year and a half ago, it took me multiple trips through the place just to get a handle on where I was when I emerged from track level and the best ways to the Amtrak and LIRR areas.
NYP could use better ADA access at the Amtrak entrances at the 8th Ave end and inside the building to get between the 2 levels. A layout diagram of NYP that I have has wheelchair access symbols at the LIRR and NJ Transit on the east end of the building off of 7th Avenue, so they exist. Amtrak probably never had the funding and clear mandate to figure out how to squeeze in elevators at the 8th Avenue entrances. The public bathrooms in the Amtrak level waiting area were closed for renovations in November and December. Don't know if the work is done yet, but the renovations were funded by stimulus money to make the bathrooms ADA compliant, so at least those are being improved. Got to figure the planned Moynihan station upgrade would include major improvements with ADA and elevator access for the NYP station complex.