quoteWhat is the best thing to preserve UK railway sleepers (I'm not
sure of the
wood), the sleepers in question will be sunk in to the ground and
others
used as soil retainers.


Is it as simple as putting creosote on and maybe using some sort of
vapour
barrier between the soil and sleeper?

Creosote is now a banned substance in the UK, railway sleepers treated
with such are not allowed to be sold, so any you buy now, new or
secondhand, will be treated with less hazardous materials, but should
still be treated. In any case an untreated one will last for many
years, and provide food, hiding places for many insects.

Mike