The only option would make the platforms level with the train doors,
instead of stepping up or stepping down. If you look at the tube
system in Toronto, Canada (Metropolitan Line type stock), the
platforms are level with the train doors and floors to enable
wheelchair users to roll on and off.

Actually, the platforms in Toronto are level with the train floors
because once you're going to have high platforms at all, that's the
obvious way to do it. They've been like that since the subway opened
in 1954, long before wheelchair access was considered an issue.

I've never understood why it was considered acceptable in London to
do it otherwise (except where tube and subsurface stock share the same
platform face, of course). Even if train floor heights have changed
over the years, it should have been possible to raise either the
platform level or the track level as appropriate to restore proper
alignment... one would think.
--
Mark Brader, Toronto | "Men! Give them enough rope and they'll dig
| their own grave." -- EARTH GIRLS ARE EASY