We are opening up a supply yard in a few weeks and wondering what we can use besides concrete barriers? We are thinking of using railroad ties. Building a wall between the bins approx 2 foot apart from each other, interlocking with each other and the back of each wall built. Putting topsoil inside each wall, there will be approx 2' growing space between each bin wall on the sides. Has anyone ever built railroad tie walls around there bins? How did they hold up? We do not want to use concrete barriers.