Middle aged woman, or anyone with younger kids would be a good support. I second the ear buds in, but not playing anything. I would bring a magazine or book and not make eye contact with anyone, and when they go above and beyond to get my attention I give them the bitchiest death glare I can. Don’t be helpful, be rude. Don’t be quiet, be loud. Body posture makes a world of difference. Shoulders up and back, sit and stand up straight and tall, and when you have to talk to someone make direct unflinching eye contact. Don’t ride in an empty car, sit by the conductor, and if it looks like you are going to be exiting into an empty station, you can always take the next stop and double back. Get pepper spray, bear spray, or even a loud foghorn.