| FIGURE | PAGE |
| ??1. | Diagram Showing Manner of Lining in Rectilinear Tunnels | 10 |
| ??2. | B. R. Value’s Device for Locating the Center Line Inside of a Tunnel | 11 |
| ??3. | Triangulation System for Establishing the Center Line of the St. Gothard Tunnel | 12 |
| ??4. | Method of Transferring the Center Line down Center Shafts | 13 |
| ??5. | Method of Transferring the Center Line down the Side Shafts | 14 |
| ??6. | Method of Laying out the Center Line of Curvilinear Tunnels | 15 |
| ??7. | Diagram of Polycentric Sectional Profile | 19 |
| ??8, 9 and 10. Typical Sectional Profiles for Tunnel | 20 |
| ?11. | Soft Ground Bucket Excavating Machine; Central London Underground Railway | 22 |
| ?12. | Column Mounting for Percussion Drill; Ingersoll Sargent Drill Co. | 26 |
| ?13. | Sketch of Diamond Drill Bit | 27 |
| ?14. | Diagram Showing Sequence of Excavation for St. Gothard Tunnel | 36 |
| ?15. | Diagram Showing Manner of Determining Correspondence of Excavation to Sectional Profile | 38 |
| ?16. | Polar Protractor for Determining Profile of Excavated Cross-Section | 39 |
| ?17. | Joining Tunnel Struts by Halving | 48 |
| ?18. | Round Timber Post and Cap Bearing | 48 |
| ?19. | Ceiling Strutting for Tunnel Roofs | 49 |
| ?20. | Ceiling Strutting with Side Post Supports | 49 |
| ?21. | Sill, Side Post and Cap Cross Frame Strutting | 49 |
| ?22. | Reinforced Cross Frame Strutting for Treacherous Materials | 49 |
| ?23. | Longitudinal Poling-Board System of Roof Strutting | 50 |
| ?24. | Transverse Poling-Board System of Roof Strutting | 50 |
| ?25. | Shaft with Single Transverse Strutting | 52 |
| ?26. | Rectangular Frame Strutting for Shafts | 53 |
| ?27. | Reinforced Rectangular Frame Strutting for Shafts in Treacherous Materials | 53 |
| ?28. | Strutting of Timber Posts and Railway Rail Caps | 56 |
| ?29. | Strutting Made Entirely of Railway Rails | 56 |
| ?30. | Rziha’s Combined Strutting and Centering of Cast Iron | 57 |
| ?31. | Cast-Iron Segment of Rziha’s Strutting and Centering | 57 |
| ?32. | Cast-Iron Segmental Strutting for Shafts | 58 |
| ?33. | Platform Car for Tunnel Work | 59 |
| ?34. | Iron Dump-Car for Tunnel Work | 60 |
| ?35. | Wooden Dump-Car for Tunnel Work | 60 | 128. Beach’s Shield Used on Broadway Pneumatic Railway Tunnel | 245 |
| 129. | Shield for City and South London Railway | 246 |
| 130. | Shield for St. Clair River Tunnel | 247 |
| 131. | Shield for Blackwall Tunnel | 248 |
| 132. | Elliptical Shield for Clichy Sewer Tunnel, Paris | 249 |
| 133. | Semi-Elliptical Shield for Clichy Sewer Tunnel | 250 |
| 134. | Roof Shield for Boston Subway | 251 |
| 135. | Transversal and Longitudinal Section of Prelini’s Shield | 252 |
| 136. | Elevation and Section of Hydraulic Jack, East River Gas Tunnel | 260 |
| 137. | Cast-Iron Lining, St. Clair River Tunnel | 262 |
| 138. | General Elevations and Sections of Shields | 270 |
| 139. | Plan and Elevation of First Bulkhead Wall in South Tube, Manhattan | 273 |
| 140. | Typical Cross-Sections of One Tube of Pennsylvania Railroad Tunnel under the Hudson River | 278 |
| 141. | Sections of Cofferdam, Van Buren St. Tunnel, Chicago | 283 |
| 142. | Showing Working Platforms and Piles Sunk in Dredged Channel | 286 |
| 143. | Showing Sheeting-Piles for the Sides of the Caisson and Trussed Beam for the Roof | 287 |
| 144. | Showing the Caisson with the Working-Chamber | 287 |
| 145. | Showing the Tunnel Constructed within the Caisson | 289 |
| 146. | Showing Sides of the Caisson and Supports for the Roof | 290 |
| 147. | Showing the Roof of the Caisson Formed by the Upper Half of the Tunnel | 291 |
| 148. | Showing the Tunnel Completed by Building the Lower Half within the Caisson | 292 |
| 149. | Transversal Section of the Caissons for the Tunnel under the Seine River | 294 |
| 150. | Showing the Joining of the Caissons at the Pont Mirabeau Tunnel under the Seine River | 295 |
| 151. | Cross-Sections and Plans of the Detroit River Tunnel | 298 |
| 152. | Tunneling through Caved Material by Heading | 306 |
| 153. | Tunneling through Caved Material by Drifts | 307 |
| 154 and 155. Filling in Roof Cavity Formed by Falling Material | 307 |
| 156. | Timbering to Prevent Landslides at Portal | 308 |
| 157. | Shortening Tunnel Crushed by Landslide at Portal | 308 |
| 158. | Extending Tunnel through Landslide at Portal | 309 |
| 159 and 160. Relining Timber-Lined Tunnel | 316 |
| 161. | Relining Timber-Lined Tunnel, Great Northern Ry | 317 |
| 162. | Relining Timber-Lined Tunnel, Great Northern Ry | 318 |
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