Plant, don't cut trees for starters
Do you suppose there was this much storm water runoff before people built houses and roads on the bluffs above the tracks? Of course not -- a single mature Douglas fir tree can hold 5,000 gallons of water! The water held by the tree is then released slowly into the ground, preventing the kind of sudden large infusion that causes slides. The sensible solution to the problem of landslides here is not cutting trees, but planting them. I would not go so far as to suggest the use of eminent domain to condemn all the impervious surfaces (buildings and roads) above the tracks -- although this tool has been used for much less reasonable purposes -- but it could be used to require tree and other appropriate vegetation plantings upslope of the unstable areas. At the very least, some of those mudslide prevention funds could be used to educate landowners about this solution and provide them with trees and/or assistance planting them.