second block distant either way throws a red light in that half of the switch light facing the approaching train.

High-Speed Locomotive for the
Prussian State Railways.

The following preliminary description of a new high-speed locomotive for the Prussian state railways, built by Messrs. Henschel and Sohn, together with the illustration of same is taken from The Engineer, London, England:

completely encased in a cover of sheet steel, tapered at the front of the locomotive in the shape of a wedge, which has been done in order to reduce the resistance of the air, whereby it is hoped to effect an economy of 250 to 300 horsepower. The driver has a position in the wedge-shaped front of the locomotive. An auxiliary driver is also carried in the driver's cab, and takes his turn in stoking with the fireman.

In order to facilitate communication on the locomotive, running boards are provided on each side inside the casing. At

This engine is intended to conduct an express traffic, at a speed of 80 miles an hour, with a train of four or five bogie corridor coaches weighing 180 tons. The estimated horse-power is 1,400.

The engine is a three-cylinder compound. The high-pressure cylinder is inside, the two low-pressure cylinders are outside and drive a second pair of wheels. The four wheels are coupled. There are besides a two-wheeled pony truck in the front, and another in the rear. The tender is carried on two bogies.

The locomotive and tender together have a total wheel base of about 68 feet, of which space the locomotive occupies rather more than one-half. The overall length from the front buffer of the locomotive to the rear buffer of the tender is about 812 feet.

The outward appearance of the locomotive and tender is peculiar. Both are

the rear of the tender a gangway has been placed, which permits through communication from end to end of the train between the engine driver and the rear guard.

The grate area of the locomotive is about 50 square feet, and about 32 hundredweight of coal are burnt in an hour. The heating surface of the boiler is 3,000 square feet. The tender carries 4,000 gallons of water and also seven tons of coal. The weight of the locomotive in service amounts to 79 tons, that of the tender about 57 tons, and the weight on the wheels does not in any case exceed that allowed by the authorities.

The type of locomotive has been indicated by Herr Wittfeld, royal councillor of architecture in the ministry of public works in Berlin. Messrs. Henschel and Sohn have thoroughly studied every detail of the proposed locomotive before

proceeding to construct it. It is intended to run the locomotive on the lines of the Prussian state railways, between Cassel, Hanover, and Berlin, and to ship it afterwards, together with three other locomotives built by Messrs. Henschel, to the St. Louis Exhibition.

An Interesting Engineering Feat.

A unique piece of engineering work was practically completed on February 14, when what may be called the west,, or Jersey wing, of the great bridge of the Central Railroad of New Jersey over Newark Bay was lowered for the first time. The bridge, which is the only one of its kind in the vicinity of New York, was constructed in an unusual manner. The immense lift or "leaf," as the engineers call it, was built in the air above the old bridge without stopping traffic. Weighing more than one and a half million pounds and 120 feet in length, each leaf was constructed in a perpendicular position directly over the passing trains.

The old bridge over Newark Bay became so weak that all trains have run across it slowly for more than a year. When it was decided to build a new structure a lift bridge was selected, largely because of the character of the traffic in Newark Bay. Tug-boats and scows are about the only craft that pass through the draw. The ordinary drawbridge has to be swung just as far around to pass a tug as a full-rigged ship, but a lift bridge needs to be raised only a few feet. This saving of time in operating the bridge will result in much quicker handling of trains, the officials believe.

It was a difficult problem to construct the new bridge in its peculiar position without interfering with traffic, and at one time the work was interrupted for two months by an accident. On August 26th last, a big wooden tower, supporting two derricks, was struck by a sudden squall and toppled over into the bay. Four men were killed and the tower had to be lifted out of the water before the work could continue. It has frequently happened that the workmen on the leaf have had to crawl about on their hands and knees because of the strong winds.

When all was ready on February 14th for the leaf to be dropped there was much

suspense among the engineers and railroad officials who had gathered to witness the inaugural. As it had never been moved before, much of the machinery used in operating it was absolutely untried. Yet when the order was given, the ponderous frame dropped into position without a hitch. So perfectly is it balanced by heavy counterweights at its lower end that a man can lower it slowly by merely turning a crank.

When the leaf dropped upon its stone support, some of the bystanders were startled to see the huge mass of steel quiver like a reed. The end rose and fell several times before settling. This elasticity, of course, is an excellent quality in the bridge.

Work has now been started upon the second leaf, which will be built east of the one recently completed. The only reason for building another span is that the charter of the New Jersey Central requires that two channels shall at all times be kept open for navigation.

An interesting feature of the new bridge is the use for the first time of gasolene engines for motive power. There are two separate 75 horse-power engines, and they are so arranged that either or both of them can be used to lift either or both leaves.

The construction of the superstructure of the bridge was scarcely more difficult than that of the piers upon which the superstructure rests. These piers had to be sunk directly in line with the old bridge, but without disturbing the piling upon which it rested. The piles for the new piers had to be sawed off at a depth of thirty-five feet below water, and at first the contractors insisted that it was impossible to cut them at that depth.

When the piles for the first pier had been driven a big box with a bottom consisting of four layers of heavy timbers was built, with detachable sides. Then the concrete pier was laid upon the bottom of the box, which was floated close to the bridge, filled with water and sunk under the old bridge, on the top of the submerged piles driven for it. Then the sides of the box were unscrewed and sent to the surface to be used in building the next pier.

The construction of the bridge was carried on under the supervision of Chief Engineer Joseph O. Osgood, of the Jersey Central, and the Bridge Engineer Austin Lord Bowman.-Railroad Men.

Caisson Disease.

Five cases of trouble in consequence of working in compressed air in a bridge caisson have been reported in this city within the last few months. In one of these it is possible that a previously existing weakness of the heart may have been chiefly instrumental in producing the observed effects, but the others were doubtless caisson disease, or diver's palsy, pure and simple. The disorder has long been recognized by the medical profession. It is not of frequent occurrence, fortunately, because only a limited number of engineers and workmen are engaged in the actual operations of driving a tunnel. Still, a singularly large proportion of these suffer to a greater or less degree. Out of sixty-four men employed in a caisson on the banks of the L 1884, sixteen had severe attacks, and it was necessary to discharge twenty-five on account of sickness. Two cases resulted fatally. Very often, when life is not lost, the ensuing paralysis is permanent. Such was the penalty paid by Washington Roebling for his devotion to duty during the construction of the first bridge over the East River.

in

Several theories have been advanced to account for this curious malady. It has been suggested that the seat of the mischief may be the brain and spinal cord, to which the blood is driven by increased external atmospheric pressure. Inasmuch as these parts of the body are inclosed in rigid walls, they can not yield to distending influences, as the heart or other organs can. Other investigators imagine that the trouble results from an effervescence of air or other gases in the blood and soft tissues. Paul Bert advanced this idea some thirty years ago, and confidence in its correctness was expressed only a few weeks ago in the Journal of Hygiene, by Dr. Leonard Hill, of London, and Professor J. J. R. MacLeod, of Western Reserve University, who have recently co-operated in experiments of their own. To the lay mind the second explanation will doubtless seem the more satisfactory of the two, because the more serious symptoms usually develop not while the subject is under pressure, but after he is liberated. The unpleasant sensations felt in the ears and the temporary deafness when first confined are, of course, practically harmless. It is when the compressed air with which the whole system has become saturated (like a bottle of soda water, charged

A number of precautions are suggested in the Journal of Hygiene article. The selection of men not over twenty or twenty-five years of age, tough and wiry in their build and abstemious in their habits, is recommended. Before they are permitted to go on duty they should be tested with light pressures and rejected if they feel any ill effects. Unduly sensitive subjects having thus been weeded out, the utmost attention should be given to one other safeguard. After men who are about to begin work have entered the "air lock," that is always interposed between the outside atmosphere and the chamber in which excavation is carried on, the necessary increase of pressure may go on rapidly. Ten or fifteen minutes will usually suffice. When the men are coming out they should be detained in the ante-chamber much longer. "Decompression" should be more gradual than compression. Even when the pressure under which they have been working is not over thirty pounds to the inch, it might be wise to take from half an hour to an hour for the reduction. For higher pressures "decompression" should be still more protracted.

The amount of pressure in a caisson or tunnel depends upon the depth of the latter below the surface of the water. The fluid is excluded by the air. Dr. Hill and Professor MacLeod think that it will prove practicable to go fully two hundred feet below water level, and to use air pressures of more than one hundred pounds to the square inch, if picked men are employed and if two hours are devoted to the liberating stage. Such an assurance is gratfying, because no one knows exactly how far down it is safe to go in engineering operations of this class. Depths never before reached may possibly be attempted in the near future. The most immediate bearing of the paper here quoted, though, is upon enterprises now in progress. It reveals the importance of taking ample time for the release of men who are today working in compressed air chambers.-The New York Tribune.

Improvements at the Baldwin Locomotive Works.

The Baldwin Locomotive Works exemplify the wisdom of making the best of unfavorable opportunities by literally go

As a

ing into the air for expansion, when the demands for room became imperative and spreading on the ground was found to be an impossibility. Precedents have been established that afford interesting guides for plants that find themselves restricted to an unsatisfactory surface area. first move in this direction all heavy hammers were removed to the Standard Steel Works at Burnham, Pa. All heavy castings are also made at the same place, besides most of them for light work. This change of location of heavy work relieves the pressure and allows the erection of a boiler shop on the second story over the old foundry, and the erection of a blacksmith shop for light work besides a frame drilling and fitting-up shop on second floor over the old blacksmith shop, and the work of fitting up throttle valves, stand pipes, dry pipes and piston valves on the second floor over the old cylinder shop. These examples of an effort to be freed of entanglements due to lack of ground area, have worked out most satisfactorily and given results looked for in an increased output. Another large factor to this end was the installation of the plant at 26th street, to be used exclusively in the final application of fittings on engine and tender prior to shipping from the works. This plant consists of a half roundhouse having 26 pits and a 100-ton crane. The drafting of engines after firing up is done through a duct under the floor line, haying vertical pipes connecting by a swiveling joint, to the engines on two adjoining tracks, the large duct leading around the house to a large chimney at the rear. The crane is arranged to traverse the pits radially, serving all. The scheming of these changes present no serious difficulties to the observer, but they must have been of weighty import to those responsible for the finished product of the works. The Railway and Engineering Review.

The Railroad Service.

During the past twelve months, according to a prominent railroad authority, there have been more changes and promotions in the service than have been made in any year in the history of railroads. In nineteen cases out of twenty good men are selected to fill higher positions, or positions of greater responsibility.

Our purpose in referring to this fact is plain. As long as a man has reasonable hopes or prospects for some day ad

vancing, or for being singled out for a higher position, he will do more, be more efficient and serviceable. The mere possibility of advancing is a stimulus. As long as a man feels that he has reached the end of his tether as to advancement, he ceases to expand. He may continue to do his duties in a hum-drum way, but the spirit of progression, of expansiveness, is absent.

In point of fact, there are probably seven men in ten in the railroad service who reasonably entertain hopes of advancement. This hope is the secret of the efficiency of the service. There is very little, if any, favoritism. Good men are selected for promotion because they are good. The distinguishing characteristic of the railroad service is that it makes each man feel that advancement awaits him.

Of course, there can be only one general passenger agent to a railroad, one general freight agent, one president, and so on. All who are in subordinate positions can not expect to reach high positions. But when we compare, year by year and decade by decade, the number of promotions for merit and capacity, it is remarkable. The truth is, positions await men faster than men are ready for them. As fast as capacity is developed in the ranks, ways will be found and places will be found to elevate the possessor of exceptional ability and fitness for special qualifications.-International Railway Journal.

Firebox width ..
Thickness of shell.
Slide valve travel..
Steam ports
Exhaust ports
Lap of valve..

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Southern Pacific Inspector of
Train Service.

The General Manager of the Southern Pacific has lately issued the following circular:

Mr. J. G. Sullivan is hereby appointed Inspector of Train Service, with headquarters at San Francisco. He is to observe and report on the following:

1. Condition of passenger train equipment and the general appearance of trains; cleanliness and freshness of coaches both inside and out; ventilation; condition of toilets, drinking water; lighting and heating apparatus; windows; plush and seat fixtures, etc.

2. Condition of equipment and character of service in sleeping and dining

cars.

3. Condition of waiting and baggage rooms and toilets, and treatment of the traveling public at stations.

4. Respect paid to flagging rules and signals; condition of train and locomotive markers, switch lights and targets, fixed station and block signals.

J. KRUTTSCHNITT, General Manager.

The inspector, who probably will have a number of assistants to aid him in the work of inspecting the 9,000 miles of the Southern Pacific lines, will devote his attention more particularly to the things named in paragraphs 1, 2 and 3 of the circular; but observations under the other four heads can, of course, be made at any time, the aim being to provide a helper and adviser for each division superintendent.

So far as concerns the testing of enginemen and other trainmen in observance of signals, this order is nothing new, for such testing has been in vogue on the Southern Pacific for over a year. This is managed, of course, by the division superintendents and tests are carried out under a general order which outlines each test as follows:

After giving date, place, etc., state whether or not signal was answered? Was train brought under control? Was train stopped and flagman picked up? Was signal to proceed answered properly? If fusee was encountered, was rear