I've always found this group a great source of knowledge and
understanding of the more obscure corners of rail ticket regulations and
I seem to remember that I even once received thanks for an 'interesting
question'! So now I'm going to push my luck with a rather convoluted
query to see if you can still rise to the challenge - and whether you're
still enjoying my questions by the end!

Tomorrow, I'll have a cheap day return ticket from Crayford to London
terminals. The morning will be easy - I'll just go straight from
Crayford to London Bridge. My query relates to the evening.

I want to nip to Greenwich on the way home. I know a Cheap Day Return is
valid for break of journey; I also know that between about 10am and 4pm
it is possible to travel, via the loop line service, from London Bridge
to Crayford via Greenwich, so if I were travelling in the daytime then
presumably I could get off the loop train at Greenwich and get back on
it subsequently to go home.

However, I will be travelling in the evening. It is still *possible* to
get to Crayford via the Greenwich line, by changing at Dartford and
travelling back up the line to Crayford - what I like to call the
'virtual loop line' (since the loop line just cuts out the change at
Dartford by turning back on itself up the other line before it gets
there)!

Indeed, at times of the week when train services are less frequent, it's
not uncommon for National Rail Enquiries to suggest travelling away from
London and changing at Dartford among its options for getting to London
from Crayford. Does this mean it is a 'valid route' for a Cheap Day
Return? If so, does that mean I can travel to, and break my journey at,
Greenwich?

As a final twist, if you do break your journey at a particular station,
are you then obliged to resume your journey at that same station? For
instance, if I wanted to get home more quickly after calling at
Greenwich than by going to Dartford and back, could I nip on a DLR or
bus to Lewisham (paid for separately by Oyster of course) and get a
train directly to Crayford from there? Or would the fact that I broke my
journey earlier at Greenwich mean I had to resume it at Greenwich too?

Thanks for your attention, and in advance for any help!

Paul