Possible lead on "AS" Marked .303 Mark IV clips?

I remember reading on this forum a while ago that .303 Mark IV clips marked with “AS” in a rectangle are unknown. Today at work I looked down at the railway tracks in the yard (1930s era) as I was walking over them. They are bolted to the sleepers with bolts marked with a large “AS” on their heads. Could this be the same company that made the clips? I have no idea how to further research this.