6/1/26 MUSIC CITY LOOP BLOG POST 

Welcome to the fifth official Music City Loop blog post! Prufrock-MB1 is tunnelling, Prufrock-MB2 will launch in June, and Prufrock-MB3 is being built! Dig more tunnels!

What Has Happened Since the April 1 Blog Post?

Construction: Since the April 1 update, Prufrock-MB1 has been tunneling, with continual machine upgrades being made as we ramp up to production speed. Often, the Nashville team will observe a machine upgrade which will increase speed/reliability - typically within 48 hours, the part is designed, fabricated, shipped, and installed.   

Rock conditions remain great, with the latest coring showing compressive strength of approx.14,000 psi.

The second tunnel boring machine, Prufrock-MB2, arrived in late April and is currently undergoing commissioning, the final phase of testing and calibration before tunneling begins in June. Lessons learned from the launch and operation of MB1 are already being applied to MB2 to improve efficiency and prepare the machine for launch.

Rock removal process:

Rock is removed from the tunnel using a continuous belt conveyor system. As mentioned in the previous blog post, excavation begins with the rotating cutterhead at the front of the machine, where disc cutters fracture and grind the rock while water is applied to reduce heat, control dust, and increase penetration rate. Hydraulic grippers brace against the tunnel walls to stabilize the machine as thrust cylinders push the cutterhead forward into the rock face. 

The excavated rock then falls onto a conveyor system that transports the material out of the tunnel into a muck pit. As Prufrock-MB1 advances, the conveyor belt system must advance with the machine. To support this process, the team uses a Vertical Cassette at the surface that maintains belt tension while allowing the belt to continuously extend forward underground.

The rock travels the length of the tunnel to a controlled area on site, where it is picked up by an excavator and loaded onto dump trucks. As tunneling progresses, the conveyor belt must also continue to lengthen. To accomplish this, the team performs belt splices, connecting new belt sections onto the existing conveyor system so tunneling operations can continue with minimal downtime.

Check out the belt splice below and the journey of the rock here!

The team is also currently commissioning the second Vertical Cassette to support continuous rock removal operations for Prufrock-MB2.

Permitting/Approvals: As noted in previous blog posts, Music City Loop requires 45 separate permits and approvals, with 37 needed in order to begin tunneling. All 37 permits and approvals required ahead of tunneling have been obtained. The remaining 8 permits relate to additional launch sites required to complete the Broadway and Airport alignments. Key approvals include: 

  • The fully executed TDOT Tunnel Permit and Lease Agreement, following over 7 months of technical review. This approval (received on February 25) authorized 25 miles of tunnel within the TDOT right-of-way and allowed TBC to begin tunneling operations within the permitted corridor. This is a significant accomplishment, and we are grateful to work alongside TDOT and FHWA throughout this process.

  • The Metropolitan Nashville Airport Authority, unanimously approved (8–0) a Music City Loop connection and station at Nashville International Airport. Station design and permitting are currently underway.

  • The Music City Convention Center Authority in downtown Nashville also unanimously (8-0) approved the Music City Loop tunnel easement, and the teams are continuing to work together to finalize the station design.

  • TBC announced the first residential Music City Loop station agreement, serving those living in the Prime, Alcove, and Paramount towers in downtown Nashville. See the announcement here!

Community Engagement: Music City Loop is grateful for the continued hospitality and engagement it has received from the Nashville community. Through ongoing conversations with residents, business owners, students, and community leaders, the team has been able to share information on the construction process and receive valuable insight into the city’s priorities.

  • Meeting with Community Leaders: Collaboration with government partners and business leaders remains a priority. We continue to offer tours at our Nashville launch site. To date we have conducted over 30 tours of the launch site. If you are interested in touring the site, please reach out to nashville@boringcompany.com, and we will do our best to accommodate! 

  • Hiring and Workforce Development: TBC continues to recruit local talent and partner with Nashville-area universities to connect with students and recent graduates. As the project continues to grow, new roles and opportunities are being created to help build a strong local workforce. For open positions, visit here.

  • Community Organizations and Volunteering: To date, TBC has engaged with over 230 community, educational, nonprofit, and professional organizations and participated in over 120 in-person volunteer events. Community engagement efforts continue to expand across Nashville. 

  • Public Inquiries: We have responded to over 170 inquiries submitted to nashville@boringcompany.com - keep the messages coming! Every message helps us better understand community priorities and build a system that reflects Nashville’s needs. 

TBC X Account: Stay up to date on all things Music City Loop by following @boringcompany on X. Updates and live X Spaces will continue to be shared as the project progresses. 

Thank you, Nashville:

The more we learn about Nashville, and the more time we spend with its state and local partners, the more exciting Music City Loop becomes. Your willingness to engage, ask questions, and help shape this project is invaluable. If there is anything we can improve or any information you'd like to see, please reach out anytime at nashville@boringcompany.com.