In the 8th Ave subway system in the garment district I can't figure out how to reach a certain area that is gated. https://photos.google.com/share/AF1Q...FvT1pQRTJMUW53
From the first picture I think you have to go left, go through some service corridors to end up the other side of those gates.
I have searched. I even thought there might be a power generator like one of the side missions.