There is no list price for a tunnel boring machine (TBM): each one is built to order and priced by quotation. The clearest public figures are for very large machines, which cost about $76 million to $80 million, while small utility tunnelling systems change hands on the used market for well under $1 million. What you pay depends mainly on diameter, ground conditions and who carries the risk.
Verified tunnel boring machine prices
| Machine | Diameter | Price | Price type and date |
|---|---|---|---|
| Herrenknecht earth pressure balance TBM, BART Silicon Valley Phase II (San Jose) | About 54 ft (16.4 m) | $76 million | Purchase approved by the transit agency, November 2023 |
| Hitachi Zosen “Bertha”, SR 99 tunnel (Seattle) | 57.5 ft (17.5 m) | $80 million | Machine cost reported when it arrived in Seattle, 2013 |
| Akkerman 420B TBM with 5000 series jacking system (Iowa, US) | 51 in (about 1.3 m) | $575,000 | Used, dealer asking price for the full system |
| MTS Lovat mid-shield module with erector, 2010 (Germany) | 3 m class | EUR 50,000 plus VAT | Used component, asking price, May 2026 |
The first two are machine prices for complete custom TBMs. The last two are used listings and cover a small pipe-jacking system and a single machine section respectively, so they are not comparable with a new large TBM.
What counts as a tunnel boring machine
A TBM excavates a circular tunnel and, in soft ground, builds the concrete lining behind itself as it advances. The main types are earth pressure balance (EPB) machines for soft, wet ground, slurry machines for very wet or loose ground, and open or shielded hard-rock machines. At the small end, microtunnelling and pipe-jacking machines install pipes and utility tunnels, typically under about 2 m in diameter.
Why the price varies so much
- Diameter: the cutterhead, main drive and thrust system scale up sharply with size. The BART machine’s main drive alone weighs more than 300 tonnes.
- Ground conditions: machines built for high water tables, mixed sand and clay, or hard rock need different cutterheads, seals and pressure systems. The BART machine was customised for high groundwater and mixed soils.
- New, refurbished or used: refurbished machines can be cheaper, but only if their diameter and ground type match the new project.
- Back-up systems: conveyors, segment handling, grouting and ventilation can be quoted separately from the shield and cutterhead.
A rule of thumb often repeated online is that a TBM costs about $1 million per metre of diameter. The two public large-machine prices above work out at roughly $4.6 million per metre, so treat that rule as unreliable for large custom machines.
The costs that are not in the machine price
The machine is a small part of a tunnelling project. The $76 million BART machine is under 1% of a project budgeted at about $12.7 billion. Buyers should plan for:
- Lead time: the BART machine was to be built over about 18 months in Germany, shipped in pieces and then assembled on site over about six months.
- Payment milestones: the transit agency said it would pay the manufacturer in stages tied to design, production and delivery.
- Launch pit and site works: Seattle’s Bertha needed a launch pit 400 ft long, 80 ft wide and 80 ft deep.
- Repair and stoppage risk: Bertha overheated in December 2013 after about 1,000 ft and was stopped for two years. The repair required a 120 ft deep access pit, and the delay led to estimated cost overruns of $223 million and years of litigation.
- Who owns the risk: when the BART agency bought its machine directly, it took on responsibility for its performance and arranged for the manufacturer’s engineers to be embedded in the team.
Buy, lease or buy used
Not every TBM is bought new. The Boring Company’s first machine, a Lovat TBM, was leased from a Wisconsin contractor before the company bought a second-hand machine and later built its own. For short utility tunnels, used pipe-jacking and microtunnelling systems are widely traded through equipment dealers. For large transit tunnels, buyers almost always order a new or substantially rebuilt machine because diameter and ground conditions must match exactly.
Questions to put in a TBM quotation request
- Machine type (EPB, slurry, hard rock) and excavated diameter.
- Ground and groundwater conditions the machine is designed for, and the geotechnical data it is based on.
- What is included: back-up gantries, segment erector, conveyors, grouting and spare cutting tools.
- Delivery terms, shipping, on-site assembly and commissioning.
- Payment milestones, warranty and the manufacturer’s on-site support.
- Buy-back, refurbishment or resale options at the end of the job.
FAQs
How much does a tunnel boring machine cost? Large custom TBMs have public prices of about $76 million to $80 million. Smaller machines are quoted individually, and used small systems can cost hundreds of thousands of dollars.
Why are tunnel boring machines so expensive? Each is custom-built for one tunnel’s diameter and ground, with heavy drives, pressure systems and lining equipment, and it is usually built and tested at the factory before shipping.
Can you rent a tunnel boring machine? Some machines are leased between contractors, but there is no published rental market for large TBMs; terms are negotiated per project.
See our heavy equipment cost guide and how we research prices.
Published November 2026. Sources: Mountain View Voice on the VTA purchase, RT&S on payments and schedule, Equipment World, Progressive Railroading, October 2025, ENR on Bertha, Bertha project history, Akkerman system listing and Lovat module listing.
