41. XU10 blocks are made in cast iron, with bores machined directly in the block, without removable cylinder liners. 42. In October and November, the two tunnel boring machines ( TBM ), christened Liva and Bette, were delivered. 43. The crossing under the main railway station is not done by the tunnel boring machine , but by manual digging. 44. Herrenknecht AG ( Schwanau ) was responsible for the delivery of the two tunnel boring machines ( TBM ). 45. The curving walls of the corridor still bear the inch-wide grooves where giant boring machines sliced through the rocks. 46. It is a marvel how they were able to build those tunnels before the advent of Tunnel Boring Machines . 47. Eleven giant boring machines , guided by satellites, dug the passages from December 1987 to mid-1991, laying concrete lining behind them. 48. Some people have use well-boring machines , designed to irrigate fields in rural areas, to dig for water in the city. 49. The bored tunnels have internal diameter of and were driven by a diameter Herrenknecht earth pressure balance tunnel boring machine . 50. The boring machine has been running into very soft earth, wells, sinkholes and underground caves as it moves under Panepistimiou.
