An escalator is a continuously moving transport with no operator and constant public contact. That combination puts wear and misuse – not control faults – at the centre of its service life.
Components and their failure modes
| Component | Job | Typical failure / call |
|---|---|---|
| Step chain and steps | Move the step band | Chain elongation, missing step teeth, step-to-skirt clearance drift, damaged step demarcation |
| Handrail and drive | Provide the moving handhold | Slip relative to steps, cracking, handrail entry damage, drive roller wear |
| Comb plate and comb segments | Transition at each landing | Broken or missing teeth – an immediate out-of-service defect |
| Skirt panels and guards | Clearance control and entrapment prevention | Clearance out of tolerance, damaged skirt brushes/deflectors |
| Machine, brake and drive | Drive the band | Brake setting, oil loss, abnormal noise, no-start |
| Safety devices | Detect step chain break, handrail speed deviation, overspeed, skirt obstruction | Switches out of adjustment, one device bridged “temporarily” |
| Balustrade and signage | Protect users and inform them | Missing signage, damaged panels, blocked emergency stop |
The checks that matter most to the public
- Comb segments – breakage is a direct injury risk; replace, never straighten.
- Step-to-skirt clearance – measure, do not estimate. Clearance drift is what entraps footwear.
- Step demarcation – worn yellow edges are a trip-and-fall claim waiting to happen.
- Handrail synchronisation – the handrail must move with the steps within tolerance; a dragging handrail pulls people off balance.
- Emergency stop function – verify at both ends and confirm the device is not blocked by furniture or a display.
- Skirt obstruction and handrail entry devices – test for function, not just for the presence of the switch.
Escalator maintenance rhythm
Escalators live in public view and take abuse: trolleys, luggage, cleaning chemicals, and constant loading. Cleaning and lubrication intervals are shorter and more critical than on an elevator, and the handrail and step band wear faster than most maintenance budgets assume. Track step chain elongation and handrail condition as trends – they predict the expensive failures.
Out of service means out of service. A stopped escalator used as a staircase is not a safe staircase: step heights and lighting assume movement. Follow the jurisdiction’s requirement for barriers and signage when a unit is stopped.
Related: system anatomy, maintenance program, forum threads on escalators.