Hi, I've seen a few posts on tackling the London Underground with a pushchair. When my son was born I had was very apprehensive about getting on the Tube tackling all those stairs. I looked for information about stairs at each station but found nothing. Just a couple of weeks ago I finally released an iPhone app with a full accessiblity guide for all stations on the Underground. Its called Mumderground...find out more here:
itunes.apple.com/gb/app/mumderground/id541375326?mt=8
I hope you find it useful!
jennie