Have these landslides been a problem in this area since the railroad was built or are they a more recent event? Most landslides occur due to heavy wet soil. Looking at the photos I see newer looking structures built above the slide area. Was drainage changed? Paved streets and roof downspouts gather more water than soil. I would think a team of geologists and hydrologists could devise a plain to re-route the hilltop drainage and with horizontal drilling drain and stabilize the slopes. The scouring from the ocean waves below the tracks is a much more serious problem.