Introduction
Aging escalators and moving walkways (hereinafter collectively referred to as escalators) inevitably experience wear, corrosion, and performance degradation after years of continuous operation. Common issues include high energy consumption, excessive noise, frequent failures, and reduced overall reliability. The actual service life of an escalator is closely related to its operating conditions and maintenance quality, as illustrated in Figure 1.
When an escalator approaches the end of its service life, proactive modernization or replacement becomes essential to ensure safety, reliability, and operational efficiency.
Unlike elevators, which can be assembled on site, escalators are typically fully assembled in factories and delivered as complete units. In new buildings, escalators are installed through whole-unit transportation and lifting. However, once a building is completed and operational, conditions for whole-unit transportation—such as large access openings, lifting points, and unoccupied spaces—are often no longer available.
Restrictions such as narrow internal transport routes, protection of existing interior finishes, and the need to maintain daily building operations make it impossible to install a brand-new escalator as a complete unit. As a result, developing practical retrofit solutions for aging escalators in existing buildings has become a critical challenge for escalator manufacturers and modernization providers.
In recent years, four main types of escalator modernization solutions have emerged:
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Partial replacement or addition of modules and components
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Complete replacement of modules and components on the existing truss
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Installing a new narrow-type escalator within the existing truss
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Full escalator replacement
The following sections introduce these four solutions in detail.
1. Partial Replacement or Addition of Modules and Components
Partial replacement or addition refers to conducting a comprehensive inspection of an aging escalator and replacing or upgrading only the necessary modules and components. Typical work includes cleaning, inspection, replacement of worn parts, installation of new functional modules, structural reinforcement, electrical control system upgrades, and cosmetic improvements.
Escalators consist mainly of mechanical and electrical systems. In the mechanical system, moving contact surfaces are subject to wear, and components under cyclic loads are prone to material fatigue, making periodic replacement of wear parts essential. Structural load-bearing components, however, usually do not require replacement unless affected by environmental factors such as corrosion.
For electrical systems, modern automation and intelligent modules—such as automatic start-stop devices, variable frequency drives (VFDs), and remote monitoring systems—can be integrated into older control systems to improve performance and energy efficiency.
Under comparable conditions, this modernization approach typically requires about one-third of the cost and labor time of a full escalator replacement, while causing minimal disruption to daily building operations. As a result, partial replacement or modular upgrades remain the most widely adopted solution for aging escalators today.
✅Advantages:
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Simple construction, short project duration, and low investment
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Modules and components can be transported without space limitations
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No need for heavy lifting or damage to existing interior finishes
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Work can be completed in phases without interrupting building operations
⚠️Limitations:
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Only a part of the components are renewed, while overall aging continues
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Obsolete components may no longer be available from manufacturers
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Compatibility issues may arise between new electrical modules and outdated control systems
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Differences in wear between old and new mechanical components may introduce new faults
2. Replacing All Modules and Components on the Existing Truss
This solution is designed for buildings where neither the aging escalator nor a new complete escalator can be transported in or out due to space constraints, lifting limitations, or protection of interior finishes.
Under this approach, all existing modules and components are removed, while the original truss is retained. New modules and components that meet the latest safety standards are then installed onto the existing truss.
This solution is best suited for original equipment manufacturers (OEMs), as it avoids the need for extensive on-site measurement, redesign, and remanufacturing of truss interfaces after dismantling. Without OEM involvement, the required surveying and redesign process can be highly time-consuming.
Compared with partial upgrades, this approach eliminates compatibility issues between old and new components, since all functional modules are replaced. However, because assembly must be performed on site—without factory-grade assembly fixtures—installation relies heavily on traditional alignment methods, resulting in longer construction time and slightly reduced assembly precision.
Additionally, the condition of the existing truss is a critical factor. Long-term operation, environmental exposure, and varying conditions between buildings—or even different floors within the same building—can lead to uneven truss aging or corrosion. In some cases, severe truss deterioration may make this solution unfeasible. On-site surface treatment of the truss also cannot match factory-level finishing quality.
From a cost perspective, this solution often involves:
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Extensive site inspections and structural assessments
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Reinforcement and surface treatment of the existing truss
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Removal of all old components and installation of new ones
As a result, both time and cost may exceed those of manufacturing and installing a new escalator in a factory environment.
3. Installing a New Narrow-Type Escalator Within the Existing Truss
This solution involves installing a brand-new narrow-type escalator inside the existing truss. It is specifically designed for buildings where transportation space is limited and interior finishes must remain intact.
In this approach, the original truss and exterior cladding are retained. All internal modules and components, as well as central cross beams inside the truss, are removed. A newly designed narrow-type escalator—featuring a reduced truss width while maintaining standard step or pallet width—is then installed within the existing truss.
During the installation process, the original truss serves as the anchoring and load-bearing structure for lifting and positioning. After installation, the original truss only carries its own weight and the exterior finishes (see Figure 2).
To facilitate transportation through restricted access routes, the new escalator is typically designed in multiple sections. These sections are transported individually and assembled sequentially inside the existing truss. This segmented design also distributes the total weight, reducing floor load during transportation and minimizing the risk of floor damage.
Because the new narrow-type escalator is fully assembled and tested in the factory, installation accuracy and quality are significantly higher than solutions requiring on-site assembly. At the same time, on-site construction time is greatly reduced, minimizing disruption to building operations.
4. Full Escalator Replacement
Full replacement involves removing the entire aging escalator, including the original truss, and installing a completely new escalator. This solution is most suitable for semi-outdoor or outdoor installations—such as building entrances or covered exterior areas—where sufficient space for transportation and lifting is available.
It is also applicable when:
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Suitable lifting anchor points are available without damaging interior finishes
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Interior renovation or redesign is already planned
The process includes the removal of the existing escalator, transportation, lifting, installation, and commissioning of the new unit. However, due to constraints such as limited transport routes, protection of interior finishes, continuous building operation, and availability of lifting points, applicable scenarios for full replacement are relatively limited.
In full replacement projects, new escalators can be designed as complete units or segmented units, depending on site conditions. Similarly, old escalators may be removed as a whole or dismantled on-site before transportation. Even with segmented designs, environmental constraints may still limit feasibility.
Looking ahead, incorporating provisions for large equipment transportation and lifting during building design or renovation would greatly improve the practicality of full escalator replacement projects.
Conclusion
Because each escalator differs in condition, operating environment, and modernization requirements, the complexity and cost of upgrading aging escalators can vary significantly. Selecting the most appropriate retrofit solution requires a comprehensive evaluation of site conditions, technical feasibility, cost, and operational impact.
With careful planning and well-coordinated execution, escalator modernization projects can be carried out safely, efficiently, and with minimal disruption—extending service life while meeting modern safety and performance standards.
