TBM Jan 16, 2021 A TBM (Tunnel Boring Machine) is a device used to drill tunnels with circular sections. This device is able to dig deep into the earth and rock by using a circular cross section. The diameter of the tunnels created by this device is in the range of one meter (using micro-tubes) to about 16 meters (modern tubes). These days, the giant TBM machine is digging a tunnel between Shahr-E-Rey square station to the Hazrat Abdolazim Al-Hassani (AS) on Tehran Metro Line 6. Saeed Rabiee https://www.tehranpicture.ir/u/8Ih