Rails to Trails preserves only the right-of-way for potential future use. Many cities have used these corridors in urban areas that are often so dijointed to probably ever be of use.

Rail banking does not salvage the track or structures, but does not maintain them either.

Many government agencies are promoting the use of railroad right-of-ways as multi-use to include trails, but I seriously question the concept. Except on the widest right-of-ways:

The trail invites persons to closer proximity to a moving train, and there needs to be a physical barrier between the trail and tracks. The trail and barrier then potentially creates issues with track maintenance and access to the railroad. WHy would any operator want the extra liability exposure of "inviting" persons to a closer proximity to trains and any potential derailment. The hikers and bikers aren't really "trespassers" any longer.