If I am running down stairs in the subway I hover my hand above them without touching it in case I need something to hold onto in the event I trip.

I will not want to be the guy that dies of a broken neck tumbling down the stairs because I didn't want to touch the hand rail.

And of course, railings are there for a reason. Which is easy to find out, if you ever experience some vertigo, some muscle or back problems or just get a bit older :p

For safety reasons. For disabled people.

Last year I twisted my ankle and for a few days the only way I could use flight of stairs was to held onto the rails.

They’re generally required by law, even at your house, but especially in public places.