My train journey from Kingston to Waterloo doesn't rely on lifts. Going, I can drive myself up the ramp if I need to (it's steep, but do-able in an electric wheelchair). Coming back, I can always get off at Norbiton, which has a ramp. Journeys which absolutely depend on functioning lifts stress me out in a way that a person with healthy legs would have trouble understanding.
The worst thing is that at King's Cross, there are three separate lifts to bring you to the surface from the tube. Not three which work in parallel, but each one doing one floor. So it's up and along and up and along and up and out, therefore either tripling or cubing the amount of stress required.
Still, it's better than sitting in a traffic jam for gods know how long.