Mark & Mel wrote:
Hi,

What 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?

Like the other responder, I would have thought that railroad sleepers
(we call them ties on this side of the big pond) were already heavily
treated with creosote.

The ones we used when we landscaped around the house and driveway were.
We bought a substantial quantity of USED railroad ties and buried some
and then built up from there to a height of maybe 20" - 24". We did not
use a barrier, we did not used crushed stone/sand beneath the foundation
course (which was underground or slightly below grade). We're in the
"Snowbelt" of the Midwest around Chicago so the climate is not kind on
outdoors wood. AFAIK, the ties we used have spent their entire life in
this weather.

They're getting pretty ragged now and we'll be replacing them with
retaining wall stones this year or next. All things considered using
the as-is, where-is ties as we did worked out pretty well.

They were laid down in 1975!