Need advice on how to protect wooden sleepers?

The type of wood treatment required to preserve and protect railway sleepers depends on the type of sleeper and the desired effect. Reclaimed Oak or other exotic hardwood railway sleepers are likely to last for at least 25 years as long as they are not buried in the ground or submerged in water. Left untreated they are likely to just turn silver or grey over time as the tanning in the surface fibres of the timber are bleached out by the sun and removed by water. For many, the grey, weathered appearance is exactly what is required. If you're looking to retain the colour for longer, a clear decking oil with UV filters will help. The oil will nourish the wood and repel water, helping to prevent the wood from cracking and splitting over time. It's worth noting that some reclaimed railway sleepers can go very dark, almost black, when a clear wood oil is applied.

New reproduction sleepers are available in both Oak and Pine. Oak reproduction sleepers will naturally last longer than their softwood alternative. Both types should be treated with an exterior wood preservative on all sides prior to installation and paying special attention to any sawn ends. They can then be treated with a clear or coloured decking oil, again preferably on all sides and cut ends prior to installation.