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Did You Know?

Learn more about the Purple Line Extension Transit Project 2018


October 4
Purple Line Extension Tunnel Boring Machines and Submarines?

Tunneling and deep-sea diving may seem like two different worlds, but they are shockingly similar. Like submariners in the ocean, a team of tunnellers on the Purple Line Extension Project will have to work under the water table. (Yes, there is water under your feet!)


April 21
What’s the difference between a thermometer and an inclinometer?

If you want to take someone’s temperature, you use a thermometer and read the line of mercury (old school) or read the digits displayed. If you want to know how far you have driven, you use an odometer, assuming that you remembered to reset it to 0 when you began the trip. If you are excavating a subway station and want to ensure that the skeleton of your station and the buildings adjoining it remain stable, you would use inclinometers and lasers and prisms and other geotechnical instruments—hundreds of them.

January 6
How does Metro preserve fossils found during excavation?

Metro hired Cogstone paleontologists to monitor excavation work at the three Purple Line Extension stations and help identify and preserve fossils found during construction. Cogstone was on duty as early as 2013. At that time, an exploratory shaft was dug opposite the Los Angeles County Museum of Art.


July 8
What can you expect during pile installation and decking work?
Constructing a station is a multi-step process. The work begins with advanced utility relocation (AUR) work and proceeds to pile installation and decking, which the project teams are gearing up for to begin at Wilshire/La Brea later this year. The purpose of piles is to support the station excavation. A deck is also installed which will serve as the temporary street surface allowing traffic to continue to flow and maintain access to sidewalks and driveways, while construction continues underneath.
June 2
How do sound walls and sound blankets work to reduce noise at a construction site?
The Purple Line Extension has implemented several construction noise mitigation efforts in order to help reduce the noise caused during construction work. Sound walls at staging yards and moveable sound blankets at construction sites are among the methods that we use. Ever wonder how they work? Stationary and moveable sound barriers are built with noise-absorbing materials that are at least two-inches thick that help reduce overall noise levels to adjacent areas.
May 4
Did you know that the project has a tree relocation and removal plan?
In order to build the Purple Line Extension (PLE) project, trees along the project alignment will need to be removed at the three new subway stations at La Brea, Fairfax, La Cienega, and the existing station at Western. But the good news is, for every tree that is removed, Metro will replace it with two at the completion of the project.
Why do backup alarms have to be loud?
If you’ve ever been around a construction site, you may be familiar with the high-pitched beeping noise coming from a work zone. These beeps come from backup alarms that alert workers to pay attention because a vehicle is reversing within the construction site, but why do they have to be loud?
Design-Build thumbnail image
What does design-build mean?
We use the term “design-build” frequently on the Purple Line Extension Project, even referring to our main contractor, Skanska, Traylor and Shea (STS), as the Design-Builder or DB, but what exactly does that mean? Design-Build refers to a project delivery method that includes the designer as part of the construction contractor’s team. The design-build process is quickly becoming the preferred method in the construction world because it saves time, money and improves the quality of the project.
January 30
Why is there no construction work happening where traffic is restricted?
A traffic control zone must be created in order to provide a reasonably safe environment while maintaining efficient movement on the road, which includes empty spaces to serve as a buffer between workers and live traffic.