Chain saw is the way to go. I have built retaining walls up to 5 feet tall using used railroad ties. Watch out for embedded stones in the creosote especially on the ends and in any cracks. It's tough on chains and resharpening or replacement chains are needed. A cutoff blade on a 4 inch grinder works well for cutting rebar to length. I used 1/2 inch rebar with 2 foot 1/2 inch wide spade bit. You can go smaller on the size of rebar and spade bit. Spade bit needs to be sharpened occasionally also. I used what I had on hand. Keep the chain saw bar well oiled. Tom

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