Close-up view of the installation

Elevators, New Construction

submitted by Dru Brooks, Liberty Elevator Corp.

NYC is home to more than 80,000 elevators, but none expand your horizons quite like Ascent. Located 1,084 ft above Midtown Manhattan atop the supertall One Vanderbilt (ELEVATOR WORLD, August 2019), dual glass elevators scale the walls of the new SUMMIT observation deck (EW, July 2021). The glass-floored elevators deliver an immersive experience for the brave at heart, with amazing views of the skyline and the city below as you climb the exterior of one of NYC’s tallest buildings.  

Reaching the SUMMIT

SUMMIT is touted as NYC’s most transformational experience, and its external glass elevators are known as Ascent. These elevators provide a thrilling, one-of-a-kind perspective of the city from One Vanderbilt’s highest elevation. The SUMMIT experience includes:

  • Ascent — the world’s largest exterior glass-floor elevators that travel to the highest panoramic viewing point in Midtown Manhattan
  • Levitation — two glass ledges suspended 1,063 ft above Madison Avenue with views of NYC below your feet
  • Après — a culinary experience where you can enjoy food and cocktails indoors or outside at the “highest urban alpine meadow in the Western Hemisphere”

Each of the attractions form part of the 65,000-ft2 entertainment area and observation deck located at the peak of One Vanderbilt, a US$3.3-billion development designed by architecture firm Kohn Pedersen Fox. Located at the corner of 42nd Street and Vanderbilt Avenue, One Vanderbilt is the fourth-tallest building in NYC, standing 1,401 ft. The full SUMMIT experience opened to the public on October 21, 2021.

Elevated Technology

The mission of Ascent was to expand the horizons of what an elevator experience could be. The elevators serve as one of the main attractions of SUMMIT One Vanderbilt, yet fit seamlessly alongside Levitation, Après and the art installations with which they share space. The feeling of floating on air as you elevate between the Chrysler and Empire State buildings in Midtown Manhattan gives SUMMIT an experiential advantage over any other observation platform on the NYC skyline. Behind the breathtaking views and striking architecture of SUMMIT lie two unique elevators that are among the most technologically advanced in the world.

Ascent is as much a technical marvel as it is an experience. The elevators were manufactured by Cimolai Technology SpA as a pair of 748-ft3 cabs made of glass and steel. The transparent floor allows for breathtaking views of the city more than 1,000 ft below your feet while the glass walls allow a 180˚view of the city skyline. The elevators ascend 120 ft up a steel track that climbs the exterior glass wall of the skyscraper, from 1,084 ft at the Après outdoor alpine meadow to the highest vantage point on One Vanderbilt at 1,219 ft. The custom steel track engages the six, 20-hp, three-phase Cimolai motors mounted above the cab in the rack-and-pinion system, guiding each 50,000-lb elevator at 83 ft/min. 

Wireless Operations

All communications with the elevators are performed virtually, without any travel cables connecting the cabs with the controls. The Siemens PROFINET communication system transfers real-time data over an Ethernet connection, allowing all elevator operations to be observed and managed outside of a traditional hardwired control panel. Due to their unique wireless communication system, these cutting-edge elevators are able to incorporate a custom handheld controller that allows the operator to remotely control each lift independently, without being present in the cab or at the call station.

In addition to the virtual communication system, power for the elevator system is drawn wirelessly from the 480V and 120V busbars that accompany the rack along the exterior south face of SUMMIT. The electrical current is transferred from the bus bars via brushes on the cab to fully power all the elevators’ operations.

By incorporating virtual controls, Ethernet communication and drawing its power from the busbars, we removed the need for any external cables to operate the elevators, making them a truly wireless system.

Rising to the Challenge

When installing glass elevators 1,000 ft above Manhattan on the outside of a skyscraper, you’d better have a world-class team of mechanics with ice in their veins. Spending more than two years on-site and tied off to one of NYC’s highest superstructures, the Liberty Elevator team worked tirelessly to install two of the most high-profile elevators under extreme conditions. 

Getting the machines into place was a challenge, with the majority of the larger pieces — such as the 30-ft-long rack segments that each weighed 16,700 lbs — needing to be hoisted via high-rise crane and fixed into place while still suspended in the wind 1,000 ft above Madison Avenue. The Liberty Elevator team of Darren Muttart, Domenick Salvatore, Charlie Gremboweic, Cole Franks and Mike Prahach worked diligently with Tishman Construction and Kuritzky Glass Co. to get this project off the ground and completed for the October 21, 2021, grand opening.

The Liberty Legacy

Recognized throughout the industry as one of the best independent family-owned contractors, Liberty Elevator Corp. continues to push the horizon of what is possible in vertical transportation. As previous winners of Project of the Year, in 2014 for its installations at the Statue of Liberty and again in 2020 for installing the unique elevator at Vessel in Hudson Yards, Liberty Elevator has differentiated itself by taking on projects that require a unique and creative approach.

Founded in 1960 as National Elevator, Liberty was born after the historic elevator installation at the Statue of Liberty in 1986. In 2018 and again in 2021, Liberty Elevator won the EW Ellie for Best Family-Owned Business. Headed by third-generation owners Douglas and Darren Muttart, Liberty Elevator has expanded its maintenance, installation and modernization reach to include New York, New Jersey, Pennsylvania and South Florida.

Douglas J. Muttart, president of Liberty Elevator, reflected on his family’s longstanding reputation in the elevator industry:

“Liberty Elevator has continued to grow despite uncertain economic times, due in part to the strong foundations we have built and an amazing team of dedicated employees. The Liberty family shares the same ideals and work ethic with those embodied by my grandfather, who started the business over 60 years ago, an unwavering commitment to quality and honesty that has sustained Liberty Elevator through three generations.”


Elevator quantity: 2
Type: Rack and pinion
Capacity/Structural: 10,000 lbs
Capacity/Operational: 15 passengers
Car speed: 83 ft/min
Travel: 120 ft
Landings: 58th and 65th floors
Front openings: 58th floor
Motor control: Two variable-frequency AC drives
Operation: Simplex
Cab interior space: 12 ft X 9 in. X 7 ft (88 ft2); Height: 8 ft, 6 in.
Car door operator: Wittur
Rack-and-pinion system: Custom rack, 10 rollers
Drive system: 6 X 20-hp, 480-VAC, three-phase gearmotors
Controller system: Cimolai Technology
Data network: Siemens wireless PROFIsafe


Owner: SL Green
Developer/Advisor: Hines
Architect: Kohn Pedersen Fox Associates
Structural engineer: Thornton Tomasetti
Architect consultant: Vidaris, Inc.
General contractor: Tishman Construction Corp.
Elevator consultant: VDA (Van Deusen & Associates)
Elevator contractor: Liberty Elevator Corp.
Elevator manufacturer: Cimolai Technology SpA
Cab and door manufacturer: Wittur Group

Related Tags

Elevator World | January 2022 Cover