Existing drainage features must not be obstructed by an ordinary repair. Show the complete threshold arrangement in the enquiry. Changes to a drainage or glazing system require the appropriate expertise and are not authorised simply because the damaged rail is nearby.
The running rail may sit within a larger threshold assembly. This service does not alter structural openings, waterproofing or the building envelope. Explain any water-entry concern separately rather than treating a track repair as a diagnosis or remedy for it.
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.
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.