Describe the suggestion
Track augments that do what they say on the tin. Derailers can be toggled on or off with redstone and when active will put stock into a "derailed" state when driven over. When in the derailed state, the train will come to a complete stop and leading stock will appear derailed (trucks/bogeys moved slightly off the rails) and can be rerailed with a large wrench. Detonators will cause smoke to shoot up from the track when driven over similar to real life railway detonators.
Applications of the suggestion
Detonators: Fun, immersive
Derailers: Making derailment scenes and for actually stopping runaways