section from Seoul to Songdo was begun in May, 1902, and two years were allowed for its completion; further extensions were undertaken, and by the end of 1904 the railway had reached Pjönjang, about 74 miles from the Yalu. The total length of the line which is now finished is 248.5 miles. From Fusan there is a branch railway to Masampo, and other projected lines are shown on the accompanying map. The lengths of the different lines and the distances of the stations from Mandschuria on the Chinese Eastern Railway are given in a tabulated form. There will ultimately be through communication from Pekin to Fusan in the far south of the Korea.

G. R R.

New York Underground Railway. S. G. FREUND.

(Elektrotechnische Zeitschrift, Berlin, 1905, vol. 26, pp. 111-6, 133-6, 162-5, 184-6, 207-13 227-30, 252-4, 270-3.)

This railway was designed and built by the Rapid Transit Subway Construction Company at a cost of 7 million pounds, the company undertaking to work the line for a period of 50 years, paying suitable interest on the capital expended to the City of New York. The railway starts as a four-track line at the City Hall, and continues for a length of 10.46 kilometres (6.5 miles) to 97th Street; from here the western branch continues underneath Broadway as a three-track line to 146th Street, and then changes to a double track up to the terminus at Bailey Avenue. The eastern branch goes underneath Central Park as a two-track line to Harlem River, and from here to Bronx Park as a three-track line. The length of the western branch is 11.44 kilometres (7.1 miles), and of the eastern branch 10.98 kilometres (6.8 miles). The two inner tracks are used for express trains, and the two outer for local trains. The railway is constructed in four different sections: as a low level and as a deep-level subway, as an elevated track, and as a river tunnel. The depth of the top of the tunnel beneath the roadway varies from 1 metre to 50 metres (3.3 to 164 feet). The maximum gradients are 3 per cent. beneath the Harlem River, and 3.1 per cent. in the East River tunnel. The tunnels are rectangular in section and are built of steel, the supporting columns are of I section and placed 1,524 millimetres (5 feet) apart. On top of these rest I beams supporting the roof, which is composed of cement arches. The cable ducts, thirty-two in number, are placed in the partition walls of the tunnel. In a small section reinforced-concrete construction is used. The station platforms are raised 1,017 millimetres (40 inches) above the track, and are 61 metres (200 feet) long for local trains, and 107 metres (350 feet) for express trains.

The power-house contains six chimneys placed in the centre and 32.94 metres (108 feet) apart. The chimneys are 68.6 metres (225 feet) high, and the internal diameter at the top is 4.57 metres (15 feet). The chimneys rest on a separate platform, carried by the

iron columns of which the station is built. There are seventy-two, Babcock and Wilcox safety water-tube boilers, with 558 square metres (6,000 square feet) effective heating surface each, working at a pressure of 15 3 atmospheres. Eight of the boilers are fitted for experimental purposes with Rosenthal superheaters of 71 square metres (763 square feet) heating surface. Artificial draught is used in the furnaces. The plant comprises nine steam-engines of 8,000-11,000 HP., coupled direct to 5,000-kilowatt alternators (for line current), three steam-turbines, coupled direct to 1,250-kilowatt generators (for illuminating purposes), and two 400-HP. steamengines, coupled to 250-kilowatt direct-current dynamos (exciters). The main steam-engines are built by the Allis-Chalmers Company of Milwaukee, and the steam-turbines and exciter steam-engines by the Westinghouse Machine Company, Pittsburg. It was considered inadvisable to put in large steam-turbines, only one satisfactory large steam-turbine having been built so far (by Brown, Boveri and Company). The contracted efficiencies of the steam-engines are specified. The condensing plant and system of oil-feed are specially described.

The line is designed to allow both express and local trains to follow each other at intervals of one minute, but at present there is a two-minute express, and a one-minute local service. The express trains consist of five motor- and three ordinary carriages. Local trains consist of five carriages, the first, third and fifth being motorcarriages. A motor-carriage weighs 40 tons, an ordinary carriage 30 tons. The starting acceleration of the trains is 0.558 metre (1.82 foot) per second, and the mean velocity of express trains, including stops, is 40 kilometres (24.8 miles) per hour. The alternators run at 75 revolutions per minute, and generate current at 11,000 volts, with a frequency of 25. The height of their field-magnets is 12,810 millimetres (42 feet), the rotating field being 9,760 millimetres (32 feet) in diameter and weighing 150 tons. The total weight of an alternator is 402 tons. A full description is given of the alternating-current plant, the exciter plant, the illuminating plant, and of the cable system to the sub-stations. There are nine sub-stations in which the high-tension alternating current of 10,000 volts is transformed down to 390 volts and then converted into direct current of 625 volts. The 1,500kilowatt converters work at 250 revolutions per minute, and their efficiency varies from 91 92 per cent. to 97.06 per cent., when the load varies from one-quarter of the full load to 25 per cent. over load. The transformers are arranged in groups of three of 550 kilowatts each, and can transform current of between 9,500 and 10,500 volts tension. Their efficiency is 96 10 per cent. at quarter load, and 98.24 per cent. at 25 per cent. over load. The general arrangement of the sub-stations, the switchboard, the system of lighting the tunnels and stations, and the precautions taken to insure illumination in the event of any circuit breaking down, are then described. The conductor rail is well covered over with wood, this being the only effective way to prevent the formation of a coating of ice in

cold weather. Many other arrangements are described in detail, and the Paper is profusely illustrated by drawings and photographs.

L. F. G.

Carriages of the New York Underground Railway.
S. G. FREUND.

(Elektrotechnische Zeitschrift, Berlin, 1935, vol. 26, pp. 723-30.)

The article is supplementary to that on the New York Underground Railway, and contains a detailed description of the new type of steel car employed, and of the electrical installations. The india-rubber insulation of the electric cables is of minimum thickness, 1.2 to 1.6 millimetre (0.047 to 0.063 inch) to prevent excessive smoke production in case of fusion.

L. F. G.

Electrification of the Long Island Railroad.

(Engineering Record, New York, 4 November, 1905, pp. 504-3.)

This is stated to be the most important electrification of a steam road now in operation. After describing the location of the various lines, making up this extensive city and suburban system of 97 miles, counting each track and sidings, the article refers to the diverse character of the train-service and its fluctuating loading, forming conditions unfavourable to electric traction. In spite of this, the management resolved on complete installation, having faith that the improved facilities afforded would result in ultimate success. In coming to a decision as to the system to be adopted, it was necessary to consider that of neighbouring lines with which connection might have to be made hereafter, as well as that to which their own line was best suited. Third rail contact, direct current at 600 volts for propulsion, and alternating current at 11,000 volts for transmission to the substations, were consequently adopted. The current will be generated at the large power-house, now nearly completed, at Long Island City, which will be one of the largest in the world, and will be equipped entirely with steam-turbines, of which, at present, there are installed three Westinghouse-Parsons turbine units of 5,500 kilowatts capacity each. The engine-room provides facilities for three more such units. The power-house is not central at present, but will be so when the operation of the Pennsylvania terminal system, and the moving of trains on the North and East

1 See preceding Abstract.

River tunnels are worked from it. The three-phase alternating current, generated at the power-house, is carried in conduits through Long Island City to the railway yards. From here the cables are brought overhead and carried on a specially designed latticed steelpole line of a novel character, being of strong construction and formed on concrete. Wherever the line crosses telegraph or telephone wires, the latter are led underneath the high-tension wires, the very substantial character of the heavy electric cables precluding their breaking. A further precaution is taken by having the poles closer together at such points. Injury by lightning is fully guarded against by lightning arresters at all substations, and special arresters and cut-out houses have been erected at all places where the transmission wires are led from overhead, and carried in underground or submarine conduits and vice versa. There are five substations located, as far as possible, at junction points, such being where the heavy loads occur, and where the arrangement of transfer switches for the high-tension circuit is possible and convenient. The largest substation at Woodhaven Junction will have, ultimately, six 1,500-kilowatt rotary converters with eighteen static transformers of 550 kilowatts capacity. Another, at Hammell, will also have the same provision, the three others having, when fully equipped, each four 1,500-kilowatt rotary converters, with transformers to correspond. All of the substations are provided on emergency with the means of augmenting their capacity to the extent of 1,000 kilowatts, through the use of portable substations, consisting of steel cars, each carrying a 1,000-kilowatt rotary converter and three static transformers.

The third rail is laid at the standard distance from, and height over, the running rail adopted by the Pennsylvania and other lines, viz., 27 inches and 3 inches respectively. The rail is laid on sleepers which extend, at intervals, beyond the line of track, and is supported by insulators made of vitrified clay. It is covered throughout its entire length by a wooden sheathing, the supports of which are fully described, as well as the methods for protection at stations, level crossings, etc.

The trains are of three-, five-, and eight-car units, all of steel; the number of motors to each being two, three, and five, respectively. All the cars are equipped with the Westinghouse pneumatic multiple-unit system of control, and each motor-car has two propelling motors of 200 HP. each, both on the same truck. The latter weigh 83,000 lbs. and are capable of maintaining a maximum speed of 55 miles per hour, and a schedule speed, including stops 1.6 mile apart, of 25 miles per hour.

The work was begun on the 15th September, 1903, and the various lines were put into operation, with an unfinished instalment of power, as above described, on the 26th July, 1905.

C. O. B.

Low-Grade Freight Cut-off of the Pennsylvania Railroad.

(Engineering Record, New York, 16 and 23 December, 1905, pp. 674-6, 707-10.)

The most interesting points about this heavy railway construction work are the power plant for driving the drills,' and the drilling operations themselves. One of the most important of the latter was the removal, in one blast, of a ledge of rock 400 feet long, rising vertically 250 feet above the Susquehanna river bank, and with sheer faces at each end. The portion of this requiring removal contained about 150,000 cubic yards.

The rocky points on the top of the ridge were first drilled with standard rock drills and blown off, a lift of about 30 feet being thus removed. Seven derrick well-drills were then brought into action, and were put to work, making thirty-eight 6-inch holes, averaging 118 feet deep, and extending 10 feet below grade. These holes were sprung with dynamite, 21 tons of which were required to make room in the bottom of them for the black powder charge. None of the holes were lost in springing, and the effect of the small shots was ascertained by the possibility of lowering incandescent electric lamps into the 6-inch holes. After the holes were properly opened below grade, they were thoroughly cooled by extending pipes from the air line down into them, and allowing the air to flow. When sufficiently cooled, they were loaded with black powder, over 100 tons of explosives, exclusive of the dynamite used in springing, being placed in the holes. To ensure the simultaneous explosion of all of the blast, six to eight exploders were used in each hole, and the blast was set off with electric current from a temporary power plant about a mile distant.

The results of this blast were quite satisfactory, the rock being so thoroughly broken up that most of the material could be removed with a steam-shovel. Stones containing up to 60 cubic yards were thrown nearly 600 feet, and it is stated that one boulder, estimated to contain 3,500 cubic yards, was thrown 300 feet. A similar ledge close by, of about 100,000 cubic yards, was removed by a single blast, carried out in the same way. Marion steam-shovels of 20 to 70 tons capacity were used in the removal of the rock.

C. O. B.

New South Wales Railway Commissioners.

(Report for the year ending 30 June, 1905.)

This report, which includes that relating to tramways, also under Government control, gives the following chief results of the working as regards railways.2

1 See post, p. 494.

The gauge of the New South Wales Government Railways is 4 feet 8 inches.C.O.B.