MICHIGAN ROADS AND FORESTS. 



Official Organ o( The Michig*n Ro*d Mkff Aw 

 SUITE 1406 MAJESTIC BUILD,! NG 



iabon and Michigan Fotfili} Aitooinon 

 DETROIT. MICHIGAN 



Frank E. Carter Editor 



PUBLISHED EVERY MONTH 



BY 

 THE STATE REVIEW PUBLISHING CO., 



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 PAYABLE IN ADVANCE. 



GREAT ENGINEERING FEAT. 



In these days of subaqueous and subterran- 

 ean transportation one becomes tired of won- 

 dering at marvels and is apt to sit back in ^his 

 car seat and take for granted the engineering 

 feat which made it possible for him to travel 

 under ground or water in comfort, says the 

 New York Sun. He reads his paper or per- 

 haps watches the blur of incandescent lights 

 on either side from the car windows, and if his 

 companion ventures to mention the wonder 

 of it all he is apt to reply, with a little con- 

 tempt at the childishness of the other, that 

 this is the twentieth century and that we are 

 living in the greatest country of the world. 



"What do you expect?" he may ask. "This 

 isn't the age of stage coaches and ferrymen." 



And in his smug contentment he is apt to 

 forget that miracles of engineering are not 

 born, but made; they do not happen, but are 

 the result of hard, courageous, well planned 

 work. 



The tunnels which the Pennsylvania .Rail- 

 road has caused to be built to connect Man- 

 hattan with Long Island, and which with the 

 tunnels under Manhattan and the North River 

 and the bridge over Hell Gate will make pos- 

 sible through trains between New England 

 and the west by way of New York, are nearing 

 completion. They were the dream of the late 

 Austin Corbin, president of the Long Island 

 Railroad. The daring of the late A. J. Cassett, 

 president of the Pennsylvania Railroad, w_as 

 great enough to conceive the scheme in its 

 entirety. 



But the real problems of construction were 

 only solved when the great steel tubes had 

 been put in place, for with every variation in 

 the strata below the river bed and with every 

 day in the progress of the work new questions 

 presented themselves. It was the greatest feat 

 of its kind ever undertaken. 



The Men Who Did the Work. 



The experience of earlier efforts in a similar 

 direction furnished object lessons but no 

 parallels. To understand fully the labor in- 

 volved one must have worked down in the 

 caissons and in the shields from the beginning 

 to the end of the task. 



But a certain superficial comprehension of 

 what it all means, a comprehension savoring 

 more of wonder than of knowledge, can be 

 obtained by a trip through the tubes in their 

 present state; with the shields which have 

 travelled slowly toward each other from oppo- 

 site sides of the river and finally have met, 

 removed, as in tube A, or with the shields now 

 being demolished, but still giving the layman 

 a faint idea of their use, as in tube B. 



A party of reporters and others were taken 

 through the tubes last week. They were met 

 at Long Island City by E. W. Moir, vice- 

 president of S. Pearson & Son, Inc., the Eng- 

 lish firm of contractors which has put through 

 the work. 



Moir is a big Scotchman, who at the age of 

 21 was chosen assistant to the builder of the 

 Forth bridge and a year later was in charge 

 of sinking the caissons, building the piers and 



constructing the cantilevers of that bridge, of 

 which the span is the greatest of any com- 

 pleted bridge in the world. He was engaged 

 by S. Pearson & Son to put through the first 

 Hudson tunnel in 1889. When this undertak- 

 ing was stopped through lack of funds he 

 returned to England and took charge of the 

 Blackwell tunnel, the greatest of its time. 



Moir wears a rough flannel suit; flannel 

 shirt, hip boots and a very hard looking felt 

 hat and has big hands and a ready smile, which 

 adds a little more to the idea you get of him. 

 With him were Henry Japp, managing engi- 

 neer of the work, who helped to build three 

 Russian and three Japanese battleships which 

 met in the late war; a couple of other men 

 the history of whose achievements would make 

 interesting reading, and Dr. MacWhirter of 

 the medical staff. 



Hospital Air Chamber. 



Dr. MacWhirter first led the visitors to the 

 hospital air chamber. This is a replica in the 

 medical offices of the air chamber in which one 

 is put under the pressure of the tunnel and 

 then passed on into the tunnel itself. In this 

 hospital air chamber Dr. MacWhirter put his 

 visitors through a preliminary training. When 

 the dial pointer showed four or five pounds 

 pressure the ear drums were driven inward 

 enough to cause considerable discomfoft and 

 a little pain. By holding the nose and blowing 

 the ear drums out again, aided by frequent 

 swallowing, this was soon relieved, and the 

 pressure, which had been stopped where it was 

 for a moment to give the tenderfeet a chance 

 to accustom themselves to it, was resumed. 

 The additional pressure seemed to make little 

 if any difference one's troubles are over when 

 he has withstood five or six pounds. When 

 the little dial measured ten pounds pressure 

 the pain was gone and the tenderfeet were all 

 right again. The air was let out gradually 

 and, graduated from the first test. 



The party then stepped into the elevator 

 and were dropped down inside one of the big | 

 steel caissons, 74 feet long by 40 wide, with I 

 two steel skins five feet apart, the space filled 

 with concrete. Some sixty feet below the 

 surface they left the elevator and started off 

 on foot toward East avenue, Long Island City. 



Tubes 23 Feet in Diameter. 



The way was through a cast iron tube 23 

 feet in diameter, the shell made up of rings 

 2 feet 6 inches wide. On a dummy track laid 

 in the tunnel stood several cars bearing strange 

 scow-shaped pieces of metal, one to a car. 

 These odd rocking things proved to be a few 

 segments of a single ring, each segment 

 weighing about a ton. It takes eleven such 

 segments and a smaller key to make up one 

 ring. 



In this Long Island extension of the tunnel 

 there was a good opportunity to see the work 

 in various stages of completion. In some 

 places workmen were filling in the rings with 

 concrete, a temporary mould of narrow boards 

 being built inside the tube to hold the cement 

 until it hardened. Further on the boarding 

 had been removed and the smooth cylinder of 

 concrete hid the rough shell. 



The visitors walked perhaps a thousand feet 

 toward East avenue and then, retracing their 

 steps, entered the under river tunnel. This 

 was identical with the other in inside appear- 

 ance for the first 500 feet. Then the visitors 

 climbed a wooden stairway nearly to the roof 

 and entered the first air chamber, where the 

 pressure is 18 pounds. 



These air chambers remind one of nothing 

 so much as a fanciful submarine passenger 

 boat, in which one might take his seat and, 

 when the door had been clanged shut and 

 tightly sealed and the machinery started in 

 motion with much fuss of whistling air, be 

 whirled under water at giddy speed. 



From the first air chamber the visitors 

 walked along a hanging boardwalk just far 

 enough below the roof of the tube to permit 

 one to stand upright. This walk was built 

 for purposes of safety, the idea being that 

 should the tunnel become flooded before the 



tube was made tight the workmen could climb 

 ladders to it and escape by it to the nearest 

 bulkhead, behind which was air pressure to 

 keep the water out. By the hanging walk the 

 party came to the second air chamber, where 

 the pressure was run up to thirty-four pounds. 



From this chamber they descended- to the 

 floor of the tunnel. A long tramp over the 

 cement smeared roadbed brought the party to 

 the junction of the Manhattan and Long 

 Island tubes. The shields had been removed 

 and the edges of the iron tubes fitted against 

 each other tightly. Mr. Moir apologized for 

 the slight difference in the angle of the tem- 

 porary floors of the two tubes, pointing out 

 that a tube' will twist a little spite of all you 

 can do. 



Every Precaution Taken. 



Branching out of the tube at this point is a 

 pump chamber over a short section of tube of 

 the same diameter as the tunnel and the same 

 construction, but running at right angles to it 

 and below it. This cylindrical chamber is 

 known as a sump. It is intended to act as a 

 drain for the pair of tubes A and B, with both 

 of which it is connected. 



In case of unforseen leakage in the tubes 

 the water would run into this sump and from 

 there the pumps would drive it out to the sur- 

 face. Neither Mr. Moir nor Mr. Japp expects 

 the sump to be needed. "It is only an addi- 

 tional precaution," they explained. 



Using this sump for a cross road, the party 

 passed into tube B and started back toward 

 Long Island City. Soon they came upon the 

 shields marking the junction of the two sec- 

 tions of this tube. The sharp biting edges of 

 the two shields rested against each other like 

 the blades of a pair of nail clippers. Just 

 behind the shield the rock and silt showed 

 through, ready to be covered with the batteau 

 shaped plates. 



These shields are ungainly looking contriv- 

 ances. Each is twenty-three feet six and a 

 half inches outside diameter by eighteen feet 

 long and weighs 315 tons. Twenty-seven 

 hydraulic jacks, nine inches in diameter and 

 with a water pressure of 6,000 pounds to the 

 square inch, rest against the flange of the 

 ring last set and kick the shield onward with 

 a r>.000 ton push. 



Through soft materials the shield cuts its 

 own way without help. When it strikes rock 

 dynamite has to be called in. When rock is 

 ahead a rough heading is driven in advance 

 of the shield and trimmed to the shield's shape. 



On the back of the shield is a human acting 

 piece of mechanism which picks up a ton seg- 

 ment of a ring and tacks it in position. Work- 

 men follow, pounding in many huge bolts. 



Leaving the shields behind, on either side of 

 the roadway the visitors now found concrete 

 trenches, broad and smooth. Under these, 

 they were told, run the conduits for electric 

 light and power. The trenches themselves 

 r orm a convenient sidewalk for passengers in 

 the event of trains being stalled in the tunnel 

 and are high enough to keep the said passen- 

 gers' feet dry in something of a flood. 

 Pretty Engineering Problem Solved. 



One of the pretty engineering problems 

 faced by Mr. Moir and his assistants came 

 from the fact that the strata of rock on each 

 side of the river sloped down, causing the 

 tunnels to emerge into boulders and quick- 

 sand, and ultimately silt and quicksand without 

 boulders. Through the Man-o'-War's reef 

 there was seldom sufficient rock in the roof of 

 the tunnel to form a safe cover. 



If enough air pressure was used to hold back 

 the quicksand and water the contractors were 

 confronted with the risk of blowing off the 

 roof of the tunnel, so weak was the resistance. 

 Mr. Moir had arranged for this contingency, 

 and by permission of the War Department 

 half a million cubic yards of clay was dumped 

 into the river over the tunnel path. This clay 

 blanket furnished the required resistance to the 

 air pressure from below, made possible the 

 work, and is now being dredged off ae;ain. To 

 the stranger all four tubes are as alike as the 

 backs o j a leek of playing cards. 



