About 20 years ago I was given a box of parkay flooring, which when split in half and reduced in length produced enough sleepers for about 200 feet of track. The sleepers when cut were then placed in a bucket of creosote for about a week then drained placed in a jig then flatbottomed rail was pinned to the sleeper using 3/8th brass flat headed pins from Brandbright, as has been said they do need knocking back down now and again, I then tried 1/2in steel pins they were refered to as gimp pins they work but do need a coat of preservative every 2/3 years.
Good luck
Shaun.