Mt. Lebanon Tunnel Ventilation Project

Pittsburgh Regional Transit is replacing four tunnel ventilation fans, controls, and other equipment that make up the emergency ventilation system of the Mt. Lebanon Transit Tunnel. 

The Mt. Lebanon Transit Tunnel spans from Mt. Lebanon Township to Dormont Borough. There are two ventilation fans and corresponding equipment on each side of the tunnel.  

PRT began running the emergency fans in November 2020 to help reduce moisture inside the tunnel in response to PennDOT inspectors discovering corrosion on metal infrastructure inside the tunnel, caused by moisture and condensation. 

The new fans will not only reduce moisture in the tunnel but will also be much quieter so that when they are in use, they should not be disruptive to residents and businesses.  

Currently the fans are scheduled to run Monday through Friday from 10am-2pm on alternating sides (Monday, Wednesday and Friday on the Mt. Lebanon side; Tuesday and Thursday on the Dormont side) to minimize disruption to residents.  

 

Project History: 

Construction began in January 2022. While completing electrical work, the contractor discovered that the metal conduit that carries electrical wires on both sides of the tunnel were damaged from moisture and must be replaced before the fans can be installed. The critical nature of this replacement significantly expands the scope of work.  

Therefore, this project will take several months longer to complete than we had originally anticipated. These delays are disappointing. However, residents and business will find that most of the additional work will not be disruptive.  

(Update March 26, 2024)
Tentatively, lane restrictions will be in place on Raleigh Avenue between McFarland Road and Grandin Avenue near the Mt. Lebanon Transit Tunnel from 9:30 p.m. Tuesday, April 2, through 4 a.m. Wednesday, April 3, to allow a crane to remove and replace the fans on the Dormont side of the tunnel.

Rail service through the tunnel will be suspended, tentatively beginning around 12:30 a.m., until the start of service on Wednesday. A free shuttle bus will be provided between Potomac Station and the Castle Shannon Park and Ride. Any passengers heading to Poplar or Arlington stations can transfer to a rail shuttle from Mt. Lebanon to those locations.

(Update March 4, 2024)

PRT began shutting down the fans on the Dormont side on March 4. The fan outage is expected to continue to late April. Durng this time, the fans on the Mt. Lebanon side of the tunnel will operate 10 a.m. to 2 p.m. on Mondays, Wednesdays, and Fridays.

There will be no impact to rail service, but single-tracking may be needed during work hours.

(Update January 16, 2024)

Electrical work on the Dormont portal has been ongoing since late October and will continue through February.

The current estimated start date for the Dormont fan outage is early March, completing in mid-April.

(Update October 31, 2023)

Installation of the new fans on the Mt. Lebanon side of the tunnel has been completed, and the fans have returned to the normal operation as of Monday, October 30, 2023.

The fans will operate on the previously utilized schedule of 10 a.m.-2 p.m. Monday through Friday, with the Mt. Lebanon side being run Mondays, Wednesdays, and Fridays, and the Dormont side on Tuesdays and Thursdays.

The replacement of the fans on the Dormont side of the tunnel is expected to begin in January or February.

(Update August 10, 2023)

Mid-August – late-September 2023

The fans on the Mt. Lebanon side of the tunnel will not run for 47 days while the old fans are replaced. During this time, the fans will only operate on the Dormont side from 10 a.m. to 2 p.m. on Tuesdays and Thursdays.

Late August 2023 or early September 2023

A crane will be used to remove the old fans and move the new fans into place. This work may require lane closures.

Early October 2023

Crews will begin work on the Dormont side of the tunnel.

Early January – mid-February 2024

The fans on the Dormont side will not run for approximately 47 days while the fans on that side are replaced.

During this time a crane will be used to remove the old fans and move the new fans into place. This work may require lane closures.

(Update June 29, 2023)

From July 17 to July 28, contractors will be working on the Mt. Lebanon side of the tunnel from 9 a.m. to 3 p.m. Monday to Friday. The tunnel fans will run only on the Dormont side, following the already established schedule of Tuesdays and Thursdays from 10 a.m. to 2 p.m. Single tracking of light rail vehicles will occur in the area during work hours.

Contractors are working to replace four tunnel ventilation fans, their controls, and other equipment that makes up the emergency ventilation system of the tunnel.

Until July 17 and after July 28, contractors will work normal hours, 8 p.m. to 4:30 a.m. Mondays through Fridays.

PRT began work inside the tunnel, which spans from Mt. Lebanon to Dormont, in January 2022. The project was delayed several months due to supply chain issues and the discovery that metal conduit was corroded and needed to be replaced before work could resume. The entire project is expected to be complete by early 2024.

Update (February 28, 2023)

Beginning Monday, March 6, contractors will resume construction activities inside the Mt. Lebanon Transit Tunnel from 8 p.m. to 4:30 a.m. Monday through Friday.

Red Line riders traveling both inbound and outbound will board light rail vehicles on the outbound platforms of Mt. Lebanon Station and Dormont Junction from 8 p.m. until the end of service each weekday. The inbound platform will be open when the contractors are not working.

Contractors will install the new fans this fall with the full project expected to be completed by early next year. Any construction activities that impact residents, businesses or riders will be announced in advance.

Update (February 3, 2023)

Supply chain issues and other unforseen field conditions continue to hamper and delay this project. The sound absorption panels, which are part of the July 2021 sound mitigation plan, have been installed inside the tunnel fan rooms. The tunnel fans have been fabricated and are being stored at the manufacturer's facility. Contractors are continuing to install conduits and cabling. The tunnel fans on the Mt. Lebanon side are scheduled to be installed by early fall 2023. The tunnel fans on the Dormont side are shceduled to be installed by early winter 2023. The final testing, controls commissioning would occur through winter 2023, with an expected project completion in early 2024.

Update (December 2, 2022)

The contractor now has new construction drawings that include the added conduit replacement and has developed a new project schedule that outlines when each phase of work will be conducted through the coming year. The drawings also allow the contractor to order all materials needed to complete the job.

Under the new project schedule, we anticipate resuming construction in the first quarter of 2023. This work will focus on the conduit replacement. The fans will continue to operate on the current fan schedule during the conduit work.  

Construction then will shift to the south portal (Mt. Lebanon side) for three months starting in June/July where we will replace the two fans on that end of the tunnel. After, work then will shift to the north portal (Dormont side) in August/September to replace those fans and also last about three months.

Our hope is to complete all work by fall/winter of 2023. A key factor in our timeline is the availability and arrival of materials needed to complete the work. Supply issues have troubled many industries, as widely reported, and this includes PRT projects. While we are hopeful, this could be a factor.

We will continue to update you weekly and may be able to be more specific about the project timeline and phases in the next couple of weeks.

Update (August 26, 2022)

While completing electrical work, the contractor discovered that the metal conduit that carries electrical wires on both sides of the tunnel are damaged from moisture and must be replaced before the fans can be installed. The critical nature of this replacement significantly expands the scope of work.

Therefore, this project will take several months longer to complete than we had originally anticipated.

These delays are disappointing. However, residents and business will find that most of the additional work will not be disruptive.

We are working with the contractor to develop a new schedule for the remaining work to be completed. This schedule will be sent by mail and will be posted to the project webpage as soon as possible.

Update (February 4, 2022)

Please note that the following work scheduled to impact riders on the inbound platforms of Mt. Lebanon Station and Dormont Junction Station will be rescheduled for a later date. Riders will continue to board as usual at Mt. Lebanon Station and Dormont Station until further notice.

Update (February 1, 2022)

Beginning Monday, February 7 through the end of April, Monday through Friday from 8pm-4:30am, riders at Mt. Lebanon Station and Dormont Junction Station will board all rail cars on the outbound platform.

Update (January 26, 2022)

Construction will occur in two phases, beginning with the Mt. Lebanon side of the tunnel. Beginning Monday, January 31, 2022, the contractor will be working weeknights from 8pm through 4:30am. To reduce any disruption to residents and businesses, work that may cause louder sounds, such as jackhammering, will be performed before 10pm. The contractor will make every effort possible to keep construction noise at a minimum.

Update (October 14, 2021)

Supply chain issues are continuing to delay the sound mitigation plan, however the fan replacement project is on-track to begin mobilization in January 2022. Construction trailers are expected to be on-site by November 2021.

Update (July 2, 2021)

PRT has finalized a temporary sound mitigation plan to install acoustical absorption panels on the inside of the fan rooms at both ends of the tunnel and have authorized our contractor to proceed with the work. Material procurement is underway and construction on the temporary noise mitigation work is expected to start in August.

Update (August 25, 2021)

Supply chain issues have delayed this the sound mitigation plan about one month. The contractor's prep work is expected to begin in September with the installation of the acoustic panels to follow. 

Update (March 30, 2021)

PRT provided an update to Dormont Borough Manager Ben Estell and Noah Pillion-Gardner, Rep. Dan Miller's legislative assistant. Our engineering consultant investigated options and has provided recommendations for near-term noise abatement. PRT is currently exploring options to mitigate the noise at the source.

We will continue to seek solutions to reduce the noise while also keeping the tunnel dry.

Update (March 10, 2021)

Operating hours for the fans have been reduced to 10am-2pm.

Update (January 26, 2021)

Operating hours for the fans have been reduced to 10am-4pm.

Update (November 2020)

In late November, inspectors for PennDOT discovered corrosion on metal objects inside the tunnel, including scaling on the tracks, that was caused by moisture and condensation. Once alerted to the issue in late December, we decided to address the issue by operating the existing ventilation fans from 8 a.m. to 8 p.m.

If you have questions or concerns, please call PRT Customer Service at 412-442-2000 weekdays from 6am-7pm, and weekends from 8am-4:30pm.