The sleepers were sourced from the same estate upon which the golf course now resides. They were not additionally distressed.
They were used to add variety and accent and re-create an era prior to 100% revetting, which was prior to the 1930s.
I speak from the perspective of someone involved in the project, but not since 2007. The bunkers were an homage to a previous era. That's what's so surprising to me about the Castle Stuart bunker haters. It was done with reverence for the past.
We loved the look and style of the bunkers in Horace Hutchinson's British Golf Links. At the same time, we wanted to avoiding having every bunker revetted like the 100,000 other links bunkers in Britain. So you get a wide variety and diversity in the shapes and looks. Isn't that something we all look for in our favorite golf courses?
And by the way, the team that did the bunkers, when they turned their attention to those bunkers that were fully revetted, they did some of the most intriguing, complicated, artistic revetting varieties I had ever seen. They did wonders on bulge and roll on the faces, changing depth of the sod cuts, alternating the right-side up, right-side down pieces...each one has its own dna. That probably gets over-looked by most golfers, but those who care to really examine them will come away impressed. And you probably can't catch those nuances from a photoessay on this website. Especially if you begin with strong prejudices.