The Towers' Design
Design Details of the World Trade Center Twin Towers
The Twin Towers employed a system of express and local elevators to decrease the number of elevator shafts and decrease transit time for tenants.
The NIST Report provides a detailed description of the elevator arragment, which was essentially identical in each Tower. 24 local elevators served the lower third of the Tower from the Concorse level, 24 local elevators served the middle third of the Tower 44th floor Skylobby, and 24 local elevators served the upper third of the Tower from the 78th floor Skylobby. The Concourse had 8 express elevators to 44th floor Skylobby, and 11 express elevators to the 78th floor Skylobby. Two additional express elevators went from the Concourse to the top floors of the Tower.