Building a garden retaining wall with old oak railway sleepers

I've got a couple of projects on the go with your used oak railway sleepers. This is the 240mm x 250mm square & notched profile that we've used in this garden.
Worthington Landscape & Design

Dutch oak square notched railway sleepers
2.6m x 250mm x 240mm (approx) Says.. supplies new and used hardwood & softwood railway sleepers throughout the UK.
Great to see the building of a solid garden wall with these sturdy old oak railway sleepers. A welcome reclaimed alternative to concrete blocks that has oodles of history and character.