Loose or damaged fixings can affect the running surface. Accessible fixing points need sound support for ordinary work to proceed. Deterioration beneath the rail may require a different assessment; covering it with a new section does not restore an unsound base.
Show the points where movement catches as well as the full track. Local damage may have a different repair option from extensive wear. Photographs help describe the problem but cannot establish that the track, rather than the rollers or frame, is the only cause.
A replacement rail or insert needs the correct shape and dimensions. Provide the system reference where available. Similar-looking tracks may support different rollers, so a generic strip should not be assumed to be a suitable repair for every sliding door.
Repair an accepted accessible rail or fit a compatible running insert or replacement section without changing the building envelope. Scope limits: Accessible non-structural running rails only. No threshold waterproofing alterations, drainage-system redesign, structural changes, major glazing or powered operators.