I
HOLING THROUGH THE FIRST TUNNEL UNDER THE HUDSON RIVER, BEING THE NORTH TUNNEL, UPTOWN LINE, MARCH 11, 1904. TELESCOPING THE METAL LINING INTO THE OLD MASONRY UNDER THE FRENCH LINE DOCK, NEW YORK CITY.

II
HOLING THROUGH SOUTH TUNNEL, UPTOWN LINE. BREAKING THROUGH THE OLD BRICK BULKHEAD AT THE FOOT OF MORTON STREET, NEW YORK, AUGUST 25, 1905.

IV
HYDRAULIC SHIELD ERECTED IN TUNNEL READY TO COMMENCE CONSTRUCTION IN SOFT GROUND. FACE OF HEADING TIMBERED IN FRONT OF CUTTING EDGE.

V
HYDRAULIC TUNNEL SHIELD, AFTER COMPLETING ITS JOURNEY FROM THE NORTH RIVER TO TWELFTH STREET AND SIXTH AVENUE, NEW YORK, A DISTANCE OF 4,525 FEET, PASSING THROUGH WEST STREET, MORTON STREET,GREENWICH STREET, CHRISTOPHER STREET AND SIXTH AVENUE TO TWELFTH STREET, IN CONTACT WITH 2,075 FEET OF ROCK IN ITS COURSE, DURING WHICH 26,000 STICKS OF DYNAMITE WERE USED TO CLEAR THE PASSAGE AHEAD, AND WITHOUT DISTURBING THE EAST-BOUND TUNNEL, ALREADY CONSTRUCTED ALONGSIDE, NOR DISTURBING THE STREETS, BUILDINGS OR INHABITANTS DURING ITS COURSE.

VI
NORTH TUNNEL, DOWNTOWN LINE. "THE LID REMOVED." HEAVY BLOW DURING CONSTRUCTION AT THE RED STAR LINE DOCK. THANKSGIVING DAY, 1908.

VII
CONSTRUCTION OF DOUBLE-DECK REINFORCED CONCRETE CAISSONS IN YARD OF THE LACKAWANNA RAILROAD, JERSEY CITY, FORMING THE JUNCTIONS BETWEEN THE UPTOWN AND DOWNTOWN LINES FOR THE ELIMINATION OF GRADE CROSSINGS, ALLOWING OPERATIONS OF TRAINS NORTH AND SOUTH.

VIII
REINFORCED CONCRETE CAISSON. SAME AS PRECEDING PICTURE WITH THE LOWER DECK ARCHED COMPLETE READY TO SINK FOR THE CONSTRUCTION OF THE UPPER DECK.

IX
FOUNDATION AND COFFER-DAM FOR THE CONSTRUCTION OF THE UNDERGROUND TERMINAL STATION AND BUILDING AT CHURCH STREET, NEW YORK, SHOWING COFFER-DAM COMPLETE AND INTERIOR CAISSONS READY FOR COMMENCING THE STEEL ERECTION.

X
TERMINAL STATION AND BUILDING AT CHURCH STREET, NEW YORK, SHOWING COMMENCEMENT OF STEEL ERECTION. 6,269 TONS BELOW FLOOR AT STREET SURFACE, 23,000 TONS IN COMPLETE BUILDING. FIRST STEEL COLUMN SET MAY 12, 1907.

XI
IRON-LINED TUBE TUNNEL CONSTRUCTED WITH A HYDRAULIC SHIELD, ON 150-FOOT RADIUS CURVE, TURNING FROM MORTON STREET INTO GREENWICH STREET, CLEANED OUT READY TO COMMENCE CONSTRUCTION OF ELECTRIC CONDUITS AND TRACK.

XII
CAISSON ENLARGEMENTS UNDER FULTON STREET, SHOWING MOUTHS OF TWIN TUNNELS, THE RIGHT-HAND ONE BEING THE WEST-BOUND TUNNEL TO PENNSYLVANIA RAILROAD; THE LEFT-HAND ONE PREPARED FOR THE FUTURE TUNNEL TO ERIE RAILROAD. THE ARCH CONSTRUCTION OF THE ENLARGEMENT, OF REINFORCED CONCRETE EXTENDING THE FULL WIDTH OF FULTON STREET AND EXTENDING EAST TO CONNECT WITH THE FIVE PLATFORM TRACKS AT TERMINAL STATION.

XIII
TYPICAL CROSS SECTION OF TUNNEL UNDER RIVER COMPLETE AND IN OPERATION.

XIV
HOBOKEN TERMINAL, SHOWING THE TYPICAL GROINED ARCH CONSTRUCTION OF REINFORCED CONCRETE USED IN STATIONS.

XV
TURN-OUT BETWEEN TWIN TUNNELS UNDER CHRISTOPHER STREET, SHOWING ENLARGEMENT UNDER CHRISTOPHER STREET OF THE FULL WIDTH OF THE STREET, AND SHOWING THE ARCHING OF THE TUBES AFTER THEY HAD BEEN DRIVEN THROUGH.

XVI
TURN-OUT AT NINETEENTH STREET AND SIXTH AVENUE, ILLUSTRATING TYPICAL CONSTRUCTION OF SIXTH AVENUE EXTENSION.

XVII
WEST END OF PENNSYLVANIA STATION, JERSEY CITY, SHOWING THE JUNCTION OF THE LINES TO NEWARK AND HOBOKEN, AND THE PENNSYLVANIA TERMINAL STUB END TUNNEL. PICTURE REPRESENTS ONLY THE SOUTHERLY HALF OF THE STATION.

XVIII
UNDERGROUND DOUBLE-DECK CAISSONS, SHOWING THE METHOD OF CONSTRUCTION NECESSARY FOR THE ELIMINATION OF GRADE CROSSINGS FOR THE OPERATION OF TRAINS BETWEEN HOBOKEN AND JERSEY CITY, AND BETWEEN TWENTY-THIRD STREET AND CHURCH STREET, NEW YORK. TOTAL WEIGHT OF THESE CAISSONS ABOUT TWENTY-FIVE THOUSAND TONS AND SUNK 86 FEET BELOW HIGH WATER IN WATER-BEARING FORMATION.
Illustration by courtesy of Scribner's Magazine.

XIX
PICTURE OF MODEL EXHIBITED AT JAMESTOWN EXPOSITION, ILLUSTRATING PRECISE METHOD OF CONSTRUCTION OF TUBE TUNNELS, WITH AIR LOCKS AND MECHANICAL APPLIANCES. THIS VIEW ILLUSTRATES CUTTING EDGE OF SHIELD.

XX
PICTURE OF MODEL EXHIBITED AT JAMESTOWN EXPOSITION, ILLUSTRATING PRECISE METHOD OF CONSTRUCTION OF TUBE TUNNELS, WITH AIR LOCKS AND MECHANICAL APPLIANCES. THIS VIEW ILLUSTRATES OPERATING FACE OF SHIELD WITH AIR LOCKS, BULKHEADS, PLATFORMS AND ERECTOR, SHOWING HALF LONGITUDINAL SECTION OF TUNNEL IN PLACE.

XXI