33. Platform Car for Tunnel Work 59 34. Iron Dump-Car for Tunnel Work 60 35. Wooden Dump-Car for Tunnel Work 60 36. Box-Car for Tunnel Work 61 37. Elevator Car for Tunnel Shafts 65 38. Ground Mold for Constructing Tunnel Invert Masonry 67 39. Combined Ground Mold and Leading Frame for Invert and Side Wall Masonry 67 40. Leading Frame for Constructing Side Wall Masonry 68 41. Plank Center for Constructing the Roof Arch 69 42. Trussed Center for Constructing the Roof Arch 70 43 and 44. A Typical Form of Timber Lining for Tunnels 73 45. Diagram Showing Forms adopted for Side-Wall Foundations 76 46 and 47. Transverse Sections of Tunnels Showing Methods for Increasing the Thickness of the Lining at Different Points 79 48. Refuge Niche in St. Gothard Tunnel 81 49. East Portal of Hoosac Tunnel 82 50, 51 and 52. Arrangement of Drill Holes in the Heading of Turchino Tunnel 91 53 and 54. Arrangement of Drill Holes in the Heading of the Fort George Tunnel 91 55. Diagram Showing Sequence of Excavations in Drift Method of Tunneling Rock 102 56. Sketches Showing Sequence of Work in Excavating and Lining the Simplon Tunnel 111 57. General Details of the Brandt Rotary Drills Employed at the Simplon Tunnel 112 58. Sequence of Excavation in the Murray Hill Tunnel 124 59. Traveling Platform for the Excavation of the Upper Side of the Murray Hill Tunnel 125 60. Timbering Used in the Murray Hill Tunnel 126 61. Diagram Showing Sequence of Excavation in Heading Method of Tunneling Rock 132 62. Method of Strutting Roof, St. Gothard Tunnel 135 63. Sketch Showing Arrangement of Tracks, St. Gothard Tunnel 135 64. Arrangement of Drill Holes in the Fort George Tunnel 137 65. Longitudinal Section of the Heading and Bench Excavation at the Fort George Tunnel 137 66. Diagram Showing the Arrangement of Drill Holes in the Heading and Bench of the Gallitsin Tunnel 140 67. Diagram Showing Modification of the Heading and Bench Method 140