Tunnels are certainly one of engineering's great achievements. Early construction projects relied on manual labor and took years to complete. That all changed with the invention of the tunnel boring machine (TBM), which is now used to build modern tunnels worldwide.

Messinger manufactures and repairs some of the larger bearings found on the business end of these tunnel boring machines. In fact, few other bearing manufacturers in the U.S. are capable of building and refurbishing bearings up to 25 feet (7.6m) in diameter.