Lessons from a Metro Station Door Replacement Programme
Replacing doors in a live station is a sequencing problem before it is a product problem. Five lessons that apply to any occupied-building door programme.
Door replacement in a working station is rarely a product problem. The doors themselves are the easy part. What determines whether the programme finishes on time is the sequence: which opening can be out of service, for how long, and what has to be true before the next one starts. Five lessons, drawn from how station refurbishments actually run.
1. The programme is defined by possession windows, not by quantities
A station may only allow a few hours a night in which an opening can be closed. That window, multiplied by the number of openings, is the real duration of the works — not the number of doors divided by a daily installation rate. Plan backwards from the possession window, and let the door specification follow from what can be installed inside it.
Where the window is very short, pre-hung assemblies with factory-set hardware are the only realistic option. Site-hung leaves with site-fitted hardware will not fit into a four-hour window, and the attempt will produce doors that latch badly.
2. Every temporary condition needs its own approval
A door removed overnight leaves a compartment open. The temporary measure — a fire-rated screen, a watchman, a closed-off zone — needs to be agreed with the operator and the authority before the first door comes out, not improvised on the night. Programmes that skip this step routinely end up with a stop-work notice in week two.
3. Interface testing is the long pole
Where a door interfaces with smoke control, access control or train operations, the integrated test is what consumes the programme. A door can be installed in a night and still fail the interface test six weeks later. Build the interface test into the schedule as a milestone per zone, and do not let installation run ahead of it.
4. Existing openings rarely match the drawing
Stations built decades ago have wall openings that are out of square, out of level, and sometimes a different size from the record drawing. Measure every opening before manufacture, and allow a frame detail that can absorb the deviation without a site-fabricated patch. The alternative is a door that fits the drawing and not the hole.
5. The handover file is part of the works
For an operating railway, the asset record is what the maintenance team will use for the next twenty years. A door that is installed but not recorded — no ID, no rating, no hardware schedule, no inspection record — becomes an unmaintainable asset within a year. Build the file as the work proceeds; reconstructing it afterwards costs more than compiling it once.
What transfers to other buildings
Any occupied building — a hospital, a mall, a school — runs the same five constraints in a milder form. Windows of access, temporary conditions, interface tests, as-built deviation, and the asset record. The product matters, but the programme is what gets signed off.
A practical starting document
One page per zone: openings in scope, the sequence, the possession window per opening, the temporary measure, the interface tests and the acceptance evidence. If that page cannot be written, the programme is not ready to start.