On Sat, 16 Jul 2005 00:30:52 +0100, "Mark & Mel"
wrote:

What is the best thing to preserve UK railway sleepers

Just ignore them. They're either creosoted already (in which case you
can't buy them nowadays), or they're a timber that's already pretty
resistant.

Arrange good drainage below them, which means gravel of a consistent
size. Don't use a barrier, as it will collect more rain than it stops
moisture heading upwards.

Search uk.d-i-y for more on sleepers.