Ian Clifton wrote:
Let’s suppose you’re going from Reading to Hanwell. You might have to
make as many as 2 changes (at Slough, and Hayes & Harlington), to reach
a station you’d simply pass through if you didn’t change. What’s the
most such changes a (sensible & perfectly informed) passenger ever has
to make?

I assume doubling back isn't allowed, otherwise you could do that in one
(changing at Paddington)?

Travelling on a Sunday in the winter, try Bourg St Maurice to Stratford
International. I make 5 changes:

Bourg St Maurice - Moutiers-Salins-Bride-les-Bains - Paris Gare de Lyon -
Chatelet les Halles - Paris Gare du Nord - Ashford/Ebbsfleet International -
Stratford International

(on weekdays the ski train stops at Ashford. I don't know if there are
direct trains from Moutiers to Lille in the winter which would cut the
changes to 3)

Theo