I have a sloping hill that had a 30 year old railroad tie retaining wall that was failing. I salvaged the good railroad ties, stood them up placed them in cement 3 feet down and 3 feet above ground. I bolted in 3 layers of pressure treated 2x12. As you can see by the pictures, I have started to back fill with cement, old ties and shrubs. I plan on stopping to pile on more and keep approximately 18" of space to drag dirt from the hillside and bring in some top soil to level off. Any words of wisdom will greatly be appreciated.