The entire length of the straight surface tracks of the cable line is 99,;-;28 ft.; of the viaducts, 4,250 ft.; of bridges, 2,124 ft.; of curves, 2,010 ft.; and of the pits, 562 ft.; making a total of 108,274 ft. of track, or rather over 20t miles, and the construction required 1,444 tons of track and slot rails, and 2,919 tons of iron sleepers.
As already stated, there are three power stati?ms on the sys tem, all similar in arrangement. 'the engines are com pound, the high-pressure cylinder being :26 in. in diameter, and the low-pressure 42 in, in diameter ; the stroke is 48 in. They are intended to develop 700 horse-power at a speed of 75 revolutions per minute. The high and low-pressure cylin ders are set side by side, and the distance between centers is 10 ft.; the total length of built-up crank shaft is 4 in. over 14 ft. The fly-wheel is 14 ft. in diameter, with rim of 14 in. face by 18 in. deep, and weighs 36,000 lbs. The first driving shaft of the winding machinery is 18 ft. 21 in. long, with two journals at the ends, and one at the center between the driving rope pulleys. In the bosses of these pulleys the shaft is swelled to 16 in. in diameter. The rote wheels, which are two in num ber, are Eft. 11,- in. pitch diameter; they are made in halves and are each grooved for fourteen 2 in. cotton ropes, the power of the engines being transmitted to the driven wheels by a system of endless rope transmission instead of by gearing. The large or driven rope wheels on the main rope shaft are 25 It, in diameter, built up of ten segments each, with a hollow boss in one piece, and ten hollow arms of elliptical section. The shaft which car ries these wheels is 10 ft. it in. long, the diameter in the boss of the wheels being 191 in. This shalt is coupled at each end to the winding shafts, which are 11 ft. 101- 17 in, in diameter in the center, and 15 in. at the bosses of the overhung rope drums. These latter are mounted on each end of the winding shaft, and each has two grooves for 2-in. cotton ropes, their diameter measured to the center of the rope being 15 ft. They drive two other rope wheels or " idlers " which are mounted on their own shaft. These idlers arc of 1 in. less diameter than the driving rope drums, and the purpose of this is always to keep the cot ton ropes taut, so that the cable itself may not have to perform any of the work of rotating the idler wheels, the necessary amount of slip required, as these slightly smaller wheels gain on the drivers, being provided for in the clutches with which the cable drums are driven. The cable
drums are loose on the extended bosses of the rope wheels, and are held to these wheels by friction disks, which are tightened up by eight screws and hand wheels in each drum. The cable drams on the winding shaft are 13 ft. in diameter, with five grooves each for 11 in. cable, and those on the driven shaft are of the same diameter, but with four grooves in each. The cable speed corresponding io 75 revolutions per minute of the 81 miles an hour.
The or American System of Cable Railways is constructed by the American Cable Railway Co. of New York, and is based upon the designs of %1r. D. J. Miller. The principal characteristic of this system is the use of duplicate cables laid parallel to one another through the tube on either side of the slot, and so arranged at the driving station that if one cable or its machinery should become disabled, the second rope can be brought into immediate use.
Each system is entirely independent of the other by reason of this duplication. The follow ing advantages are claimed : Besides operating the road uninterruptedly, the motive power is more durable, as ample time can be allowed for close inspection and needed repairs, thereby prolonging the life of both cable and machinery. Roads operated by duplicate cables can run steadily twenty-four hours per day, while with but one rope this is not possible. as some time must be devoted to examination and repairs. This system is in use in New York City on the Tenth Avenue road, where the cables are worked independently in the following manner ; At the point where the cable is first carried into the conduit, sheaves 4 ft. in diameter (called elevating sheaves) are used to elevate the rope to a line where iL may be received into the gripper. The sheaves are placed in a frame having trunnions at the ends. on which the wheel tilts. See Fig. 6. This tilting is accomplished by a horizontal lever moving in a ver tical plane, and is operated by the grip as the ear passes. The normal line of the elevating sheave is in the line of the travel of the grip, and as the car approaches the grip rides on a horizontal lever, which is depressed by the movement and weight of the grip, and in turn tilts the sheave.. The grip then passes, the sheave resumes its former position, and the cable is laid between the grip jaws. The cable having been thus received into the gripper at the starting point, is carried to theeud of the line, passing freely through the grip jaws in bring ing ears to a standstill.