Elevator Anatomy - Schematic of Traction & Hydraulic Elevator Systems Expert Overview

The forensic experts at Robson Forensic are frequently retained to investigate injuries and construction claims related to elevators and escalators. In this document our elevator experts have provided generalized schematics of a hydraulic and a traction elevator. These illustrations are intended to be helpful for attorneys and adjusters to understand the technical aspects of this equipment and to facilitate a meaningful discussion with our technical experts.

Elevator Expert Witness

Elevator Anatomy

There are many different types of elevator configurations, but the majority of passenger elevators fall into one of two categories; hydraulic or traction. The primary difference is that a hydraulic elevator uses a hydraulic piston to raise and lower the elevator car, while a traction elevator uses a geared or gearless hoist machine along with a counterweight to control the travel of the car.

In this section we have provided a generalized schematic of each, which may be helpful in discussing the specific components in your case.

Hydraulic Elevator Expert

Traction Elevator Expert


Download PDF


Case Components

Having an expert involved in your case as soon as possible will assist in ensuring you obtain the records / documentation required for a thorough investigation. Understanding elevator and escalator industry terminology and how companies structure their operations is key. Simply asking for the “maintenance” records for the equipment in question may not be enough. Knowing what additional information may be useful to your case is another reason why retaining an expert early is important.

As with any accident, many different factors may play a part in identifying causation. Having an expert with the technical expertise to help you understand the complexities of elevator ownership, maintenance and certification requirements is critical to the development of your case.

Identify the Owner

It will be necessary to identify the property owner or owner’s property management firm. One of these parties will have contracted with the elevator maintenance service provider. Each is obligated to exercise reasonable care in maintaining the premises. Having an expert retained early in your case will assist you in identifying the role of the owner or owner’s management firm as it relates to your case.

Site Inspection

No matter how much time has passed since the incident to your being retained as either plaintiff or defendant’s counsel, it is important that you retain an expert early and arrange for your expert to make an inspection of the equipment and site conditions as soon as possible. This will enable your expert to have a better understanding of the physical conditions that may factor in when determining causation. Having an expert with the experience to identify and understand the operating characteristics of most elevator and escalator manufacturer’s (major and independent) equipment and applications will help you better understand the technical aspects of your case.

Applicable Codes

While location of the equipment will determine the Authority Having Jurisdiction (AHJ), the applicable Code is determined by the date of installation or last modernization of the equipment. Knowing the applicable elevator Code(s) as they relate to your case is not enough. You will need an expert with extensive knowledge of the appropriate related building, fire, electrical and life safety Codes as applicable to the building and equipment involved.

Elevator Injury Investigations

Our elevator and escalator experts are industry veterans who worked for manufacturers, installation contractors, and maintenance companies. Our experts understand how this specialized equipment is designed to function and can reliably identify if a malfunction in elevator or escalator equipment contributed to the injuries or loss in your case.

For more information visit our Elevator/Escalator practice page.

Featured Experts

Dennis W. Olson, Elevator & Escalator Expert

Dennis W. Olson, C.E.I.

Elevator & Escalator Expert
Dennis is an elevator and escalator expert with more than 35 years of industry experience. His casework includes matters related to the design and construction, modernization, maintenance and… read more.
Michael Vallone, Elevator & Escalator Expert

Michael Vallone, C.E.I.

Elevator & Escalator Expert
Michael Vallone is an elevator and escalator expert with over 20 years of industry experience as a field mechanic, maintenance supervisor, and operations manager. His expertise extends to all aspects… read more.


View All Articles

Deadly Elevator Fall - Expert Interviewed by NY Times

By Dennis W. Olson
Expert Article

Elevator expert, Dennis Olson was interviewed by the New York times regarding a deadly elevator mishap in Williamsburg, Brooklyn that killed one man. Deadly Elevator Fall Spurs Look at Brakes and Load…

Escalator Anatomy - Expert Diagram to Assist in Forensic Discussions

By Dennis W. Olson
Expert Overview

The forensic experts at Robson Forensic are frequently retained to investigate injuries and construction claims related to elevators and escalators. In this document our escalator experts have…