Tall and wide-shouldered but never have this kind of subway standoff. I considered stuff I might be doing differently, in case you’d like to try one of them:

1. I usually look past people toward where I’m going. It’s a subtle cue but most pedestrians read it. This works well to avoid sidewalk collisions also.
2. I tend to twist sideways while moving in tight spaces, lower my front shoulder slightly, and duck a bit through train doors. I think that body language might be doing a lot of work to signal where I’m going.
3. If someone is oblivious to the above, I’ll make eye contact and smile, and that’s usually enough for them to realize I can’t get past. If they’re facing away I’ll say something like “pardon me, this is my stop” and if they can’t hear me either I’ll touch their arm or back to get their attention.

Hopefully one of these work for you!