Do this because a broken saw blade or band can injure you or kill you.

Just an out-of-the-box thought here- is it possible to cut timber with a water jet? This process seems to be chiefly used for precision cutting of relatively thin metal, but I wonder if it'd work for this application? While there wouldn't be any saw blade or chain to get gummed up, I suppose it's possible creosote might muck up the abbrasive in the water, causing an even worse problem, and even if this isn't a problem water jet cutting of large timbers might be a prohibitively expensive process.

OTOH it might be worth asking someone in the business.

Edit- a quick google search shows it is definitely possible to cut relatively thick wood (at least up to 4 inches or so) using a water jet, so maybe it's worth researching further.