Maintenance, inspection and lubrication

By the middle of the term, Tamsin had a routine. Monday and Tuesday nights at Brackenridge, Wednesday at the airport walks, and Thursday and Friday nights at the transit station after the last trains, when the agency released two units at a time. Each visit followed a printed checklist drawn from the unit's maintenance control program, and each ended with an entry in the unit's record. Nell checked the entries every week. "The checklist tells you what to look at," she said. "The record is what tells the inspector, the owner and the next mechanic that it was looked at, what you found and what you did about it. An escalator that is well maintained but badly recorded looks exactly like one that isn't maintained at all." This lesson covers the maintenance control program, routine maintenance and lubrication, cleaning, the periodic tests and inspections, and the records that tie them together.

The maintenance control program

Part 8 of the code requires every escalator and moving walk to have a maintenance control program, usually called the MCP. It is a written program, specific to the unit, that lists the maintenance tasks, how often each is done, the periodic tests and their intervals, the procedures used, and the records kept. It is based on the maker's instructions and the code, and adjusted for the unit's duty and environment: a transit escalator running twenty hours a day outdoors needs more frequent attention than a mall unit indoors. The MCP must be kept on site or available to the inspector, and the records must show that the work in it has been done. In Washington and Seattle, inspectors routinely review the MCP and the records during periodic inspections, and missing or incomplete records are a common finding.

Northcrest's MCPs for the three sites differ mainly in their intervals. The Brackenridge units are visited twice a month, the airport walks weekly because of the cart damage, and the transit station's units weekly with a daily walk-past by the agency's staff, who check that the units are running, clean and undamaged and report anything unusual. Some items in each MCP are tied to running hours rather than calendar time, such as gearbox oil changes and chain lubricator refills, so the crew reads the running-hours counter at each visit.

Routine maintenance on a visit

Every visit starts the way lesson 1 described: barricade both landings, inform the building, and ride the escalator in its running direction before anything else. Riding tells a trained mechanic a great deal: a bump at one place, a click on every step, a handrail that drags or lags, a noise from the drive, a vibration through the steps. Then comes the walk-around with the unit running: the comb teeth, the skirt brushes, the handrail surfaces and inlets, the lighting, the caution signs, the stop button covers and the safety zones. Only then is the escalator locked out, the landing plates lifted and the machinery inspected.

In the upper machine space, the mechanic checks the drive for oil leaks, noise and heat, the gearbox oil level, the brake linings and its operation, the main drive chain tension and lubrication, the controller's fault log, and the condition of the wiring and safety devices there. In the lower pit, the tension carriage position and its springs, the broken step chain device, the step upthrust device and the pit's cleanliness are checked. Through the step window, steps, rollers and chains are inspected as the band is inched past. Every item found is either corrected on the visit or written up with a plan, and anything that affects safety is corrected before the unit returns to service.

Lubrication

An escalator has several lubrication systems, each with its own oil or grease. The step chains and the main drive chain are lubricated by the automatic lubricator, whose reservoir is refilled with the maker's chain oil and whose timer and delivery are checked. The gearbox is filled with gear oil of the grade on its data plate, checked at every visit and changed at the maker's interval or when an oil sample shows wear metals, water or breakdown. Motor and shaft bearings are greased to the maker's schedule with the specified grease, in the specified quantity, because over-greasing bearings makes them run hot. Handrail drives, step treads, comb plates and brake linings are never oiled: oil on them causes slip or brake failure.

The rule Nell repeated most often was to use the maker's lubricants and quantities and to keep them out of places they do not belong. Oil that drips from over-oiled chains onto the return steps is carried around the band, picks up dirt and ends up in the drip pans and on the tracks. At the transit station, where the units run long hours, Northcrest has the gearbox oil sampled twice a year; a rise in iron or bronze in the sample is an early warning of gear or bearing wear months before any noise appears.

# Maintenance due dates by calendar and by running hours for one unit
from datetime import date, timedelta
today = date(2026, 11, 2)
hours_now, hours_per_day = 61850, 20
tasks = [("lubricator refill and delivery check", "days", 14, date(2026, 10, 22)),
         ("step inspection through the window", "days", 30, date(2026, 10, 5)),
         ("safety device test rotation", "days", 90, date(2026, 8, 20)),
         ("truss and drip pan cleaning", "days", 180, date(2026, 4, 20)),
         ("gearbox oil change", "hours", 10000, 52300),
         ("handrail drive roller replacement", "hours", 15000, 47200)]
for name, kind, every, last in tasks:
    if kind == "days":
        due = last + timedelta(days=every)
    else:
        due = today + timedelta(days=(last + every - hours_now) / hours_per_day)
    days_left = (due - today).days
    flag = "OVERDUE" if days_left < 0 else ("due soon" if days_left <= 14 else "")
    print(f"{name:<38} due {due}  ({days_left:+d} days) {flag}")

lubricator refill and delivery check   due 2026-11-05  (+3 days) due soon
step inspection through the window     due 2026-11-04  (+2 days) due soon
safety device test rotation            due 2026-11-18  (+16 days) 
truss and drip pan cleaning            due 2026-10-17  (-16 days) OVERDUE
gearbox oil change                     due 2026-11-24  (+22 days) 
handrail drive roller replacement      due 2026-11-19  (+17 days)

This illustrative run is for one of the transit station's units, which runs about twenty hours a day. The truss cleaning is overdue, which matches what Tamsin had seen: a drip pan with a layer of dirt and oil at the lower end. The gearbox oil change is due in a few weeks, so it was booked for the next release window, and the crew planned to take an oil sample before draining.

Cleaning

Cleaning is a safety task on an escalator, not just appearance. The truss collects dirt, paper, cigarette ends, food, lost items and oil, and on a busy unit the amount is surprising. Built up in the drip pans and the pits, it is a fire load directly under the steps, it hides oil leaks and cracked parts, and it can jam the tension carriage or foul the step devices. Truss cleaning is done with steps removed to open a window, using vacuum equipment and scrapers, with the unit moved only on inspection and nobody inside the truss while it moves. Step treads are cleaned with step-cleaning machines that run on the steps while the escalator moves slowly on inspection; clogged grooves let the comb teeth ride up and can break them. Skirts and handrails are cleaned only with the maker's approved products, for the reasons given in lessons 5 and 6.

Periodic tests and inspections

The code's periodic tests for escalators and moving walks, in section 8.6.8.15, are done at least every year, and the edition in force lists them. They include the operation of every safety device that the unit has, including manual reset where required, the brake tests described in lesson 8, the handrail speed monitoring and inlet devices, the measurement of chain stretch, the step and skirt performance index and loaded gaps, the comb-step impact devices, the step level and upthrust devices, the skirt obstruction devices and, in higher seismic zones, the seismic devices. Each result is recorded with the method used, the values measured, who did it and the date.

Separately, the authority inspects the unit. In Washington, the Department of Labor and Industries inspects escalators and moving walks every year and issues an annual operating permit, which must be displayed; Seattle does the same for units within the city. The inspector looks at the unit, reviews the MCP and the records, may witness tests, and issues a report listing any items to correct, with deadlines. Northcrest's practice is to schedule its own annual tests a few weeks before the authority's inspection, so the inspector sees a unit that has just been tested and records that are complete.

Findings inspectors make most often

Nell kept a list of the items inspectors had written up on Northcrest's escalators over the years, and she gave it to Tamsin as a checklist of her own. The most common were safety zones obstructed by displays or barriers, missing or damaged caution signs, broken comb teeth, worn or missing skirt deflector brushes, handrails with cuts or gaps at the splice, lighting below the required level at a comb, stop button covers whose alarms did not sound, dirty trusses and drip pans, and records that did not show a test had been done. Almost all of them are found and fixed on a routine visit if the mechanic looks for them, which is why the walk-around comes before the machinery on every visit.