Moving Walkway

Overview

A moving walkway (also travelator or moving sidewalk) is a conveyor that carries standing or walking passengers along a horizontal or gently inclined path. Airports use long horizontal units, commonly 40 to 110 m per span, to shorten concourse walks; retail buildings use inclined versions, up to 12 degrees, that carry shopping trolleys between floors where an escalator could not. Mechanically it is an escalator unrolled flat: the same chain-driven endless band, comb landings, balustrades and moving handrails, but with flat pallets instead of folding steps.

At the standard 1,000 mm width and 0.5 m/s, theoretical capacity is around 9,000 persons per hour, and unlike an escalator the flat surface lets passengers walk, adding their own speed to the band's. Codes (EN 115-1 in Europe, ASME A17.1/CSA B44 in North America) cap speed at 0.75 m/s for pallet-type units; most run at 0.5–0.65 m/s.

Structure

Everything mounts inside the Truss, a welded lattice girder assembled from bolted Truss Sections and bearing on the floor slab through elastomer-padded Support Angles. For very long airport installations, intermediate supports carry the truss every 15 m or so. The pallet band runs along the top chord, returns underneath, and the soffit is closed with Sheet Metal Panel cladding.

How it works

The Drive Machine sits in the pit at one end. A three-phase induction motor drives two helical Helical Gear Pair reduction stages inside the Gearbox Housing; the output shaft carries the two Drive Sprockets that engage the band's chains. Long units split the load between drive units at both ends, or use intermediate modular drives spaced along the truss so chain tension never accumulates over the full length. A spring-applied Machine Brake clamps the shaft whenever power is removed.

The Pallet Band is the moving surface: several hundred die-cast aluminium Pallets, each about 1,000 × 400 mm with longitudinal grooves, pinned between two heavy Pallet Chains. Each pallet rides on polyurethane-tyred Pallet Rollers that follow the Guide Track through the carry run, around the end sprockets, and back along the return run inside the truss. Because the path is flat, the pallets never articulate relative to one another as escalator steps do, the band is simply a slat conveyor built to passenger-safety tolerances, with gaps between pallets held to a few millimetres. At the idle end, the Tension Carriage floats on springs to take up chain wear; if a chain breaks or stretches beyond limit, the carriage moves far enough to trip a safety switch.

Passengers hold the Handrail System on each side: an endless C-section Handrail Belt of rubber over steel cords, driven by friction Handrail Drive Wheels geared off the main shaft so handrail and pallet speeds stay matched within the 0 to +2% band EN 115 requires. A Handrail Tensioner keeps the belt taut and it slides on a low-friction Handrail Guide along the balustrade top. The Balustrade itself is tempered Glass Panels clamped at the Deck Board, with Skirt Panels and Deflector Brushes closing the gap beside the moving pallets.

Landings

Each end is a Comb Landing. Toothed Comb Plate segments mesh into the pallet grooves so that anything on the band, shoe soles, trolley wheels, luggage straps, is lifted onto the fixed Landing Plate rather than carried into the machine. The combs are sacrificial: a jammed object displaces the comb segment and trips the Comb Switch before damage propagates.

Control and safety

The Control System soft-starts the band through a variable-frequency drive built on IGBT Power Modules and, on energy-saving installations, drops to a 0.2 m/s crawl when photocells at the landings report no traffic, ramping back to rated speed as a passenger approaches. The Safety Devices chain is wired in series through the brake circuit: an Encoder on the main shaft detects overspeed or unintended reversal, Hall Sensors watch handrail speed, Skirt Switches trip on side-gap obstruction, Handrail Entry Switches guard the handrail inlets, and covered Emergency Stop Button buttons stand at each landing. Any trip opens the chain, drops the Machine Brake, and stops the band at a controlled deceleration, fast enough to limit a dragged object, slow enough not to topple standing passengers.