53. Q.-What is the trouble if a lubricator feeds faster when the throttle is closed than open?

A. The trouble is in the choke plugs being worn too large or the equalizing tubes partially stopped up.

54. Q.-What do you consider the proper amount of oil that should be fed through a lubricator in drops per minute? Why?

A.

Under ordinary conditions would feed about five or six drops per minute to the cylinders and one drop per minute to the steam cylinder of the air pump. Would feed this amount to properly lubricate the parts.

55. Q.-What is a steam dome?

A. A steam dome is a cylindrical chamber made of boiler plate and is riveted to the top of the boiler. On crownbar-stayed boilers the dome is generally placed over the front part of the crown sheet, the crown braces extending up from the crown bars and riveted to the sides of the dome; in radial-stayed boilers the dome must be placed ahead of the firebox, as it would interfere with the proper staying of the crown sheet were it placed over this sheet.

56. Q. What are the purposes of a steam dome on a locomotive?

A. It serves as an additional steam space to the boiler, and also as a location for the stand pipe and throttle valve at a considerable distance above the water so that dry steam will be used in the cylinders; it also forms a convenient stand for the whistle and safety valves.

57. Q.-Explain the difference between a "wide" and a "narrow" firebox engine?

A.-A wide firebox engine has the firebox widened out and set on top of the frames and extends out over the rear driving wheels, while with a narrow firebox engine the firebox is long and deep and fits in between the frames.

58. Q.-Has the more recent or wide firebox type any advantages over the narrow firebox? If so, what are the advantages?

A. Yes. The wide firebox provides a much larger grate area than can be obtained with the narrow firebox fitting between the frames, thus allowing a poor grade of coal to be burned. It is also easier to fire properly than a long, narrow firebox.

59. Q.-Describe in a general way the construction of a locomotive firebox.

A. The firebox is rectangular in form and consists of the back tube sheet (in front), the crown sheet (on top), the two side sheets, the door sheet (in back) and the grate at the bottom. It is secured to the back part of the boiler, and its sheets are surrounded by water, being separated on all sides from the outside shell by a distance of from 3 to 4 inches; this space is called the water leg. The firebox sheets are secured to the outside shell by means of stay-bolts screwed through both sheets. The bottom of the water leg is formed by a wrought iron or cast steel ring called the mud ring, to which the outside and the inside sheets of the firebox are riveted. Below the grate is the ashpan, which is provided with dampers to regulate the supply of air admitted to the firebox from underneath. The crown sheet is supported either by means of crown bars or radial stays.

how many

61. Q.-Approximately stay-bolts are required in a firebox of average size?

A. Considering the stay-bolts proper there are usually from about 800 to 1,100 depending upon the size and shape of the firebox.

62. Q.-What is the purpose of using stay-bolts in a locomotive firebox?

A. They form a support for the firebox sheets by fastening them to the main shell of the boiler, and enable them to resist the strains to which they are constantly subjected when under pressure.

63. Q.-A small hole is sometimes bored in the outer end of a stay-bolt.. For what purpose is this hole placed there?

A. Should one of the bolts become broken or cracked it will be indicated by water escaping through the hole. 64.

Q.-What do you understand by

a mud-ring?

A. The mud-ring is the foundation of the boiler and consists of a wrought iron or cast steel ring encircling the bottom of the firebox, and to which the outside and the firebox sheets are riveted, the

rivets passing through both sheets and the mud-ring and headed over on the outside.

which has attended the innovation abroad must necessarily impel some serious consideration of the subject. In several

A. It is part of the water space of the boiler and is the distance between the firebox sheets and the outside sheet.

66. Q.-Describe in a general way a locomotive boiler.

A. It consists of one or more cylindrical forms attached to a rectangular form and having a smokebox in front. In the rectangular form is placed the firebox, while the cylindrical form contains the flues, which connect the firebox with the smokebox.

67. Q.-What are the main essentials in a locomotive boiler so far as steaming is concerned?

A. That the boiler be kept clean and as free from mud and scale as possible, and that it be kept free from leaks. 68. Q.-Name some of the very necessary points to be observed in firing a locomotive in order to obtain the most satisfactory results.

A. The coal should be broken to the proper size before being fired, so that it can be handled easily and burn more economically. See that the proper amount of air is admitted through the grates to supply enough oxygen to burn all the coal perfectly. An even pressure of steam should be kept up while the engine is working; also the firebox temperature should be maintained as high as possible by adding small quantities of coal at regular intervals and closing the door after each scoopful. Avoid opening the fire door only when absolutely necessary, as the cold air entering will reduce the temperature of the firebox and may cause leaks. Avoid banking the fire and allowing thin spots to form, as the banked portions in the fire will produce very little heat, and the thin places may cause holes and allow an excessive supply of cold air to enter and cool off the temperature of the firebox.

Poppet Valves for Locomotives.*

The possible use of poppet valves to effect the steam distribution in locomotive cylinders has never been viewed with favor in this country, but the success *From American Engineer and Railroad Jour

nal.

fiedly endorsed by the highest authorities (and this is especially true in the instance of the Prussian State Railways, where it is embodied in the very latest types of locomotives). Particularly this motion is said to be applicable to high speeds, working safely and exactly at. revolutions ranging from 250 to 300 per minute. The type employed is that of Lentz, and it was prominently featured in some powerful express engines at the Brussels exhibition.

In this clever and decidedly interesting treatment of a somewhat difficult proposition the four double-seated poppet valves, controlling the outlets and inlets, are arranged to operate vertically in a cast iron valve case which is bolted steam tight to the cylinder proper. The actuating mechanism of the valves consists of a simple cam rod, corresponding to and about in the same location as the valve stem in American practice, the movement of which, derived from the outside link valve gear, raises and lowers the valves on their respective seats at the proper interval.

The conclusions which inspired this gear were based largely on the knowledge of the increasing use of high pressure, and particularly of high degrees of superheat which revealed deficiencies in the ordinary D and piston valve gear. It was also appreciated that with the ordinary valves a complex guide motion was necessitated which was scarcely suited for high speeds. A further advantage claimed for this system is the positive closing of the valves even with high degrees of superheat, as well as favorable conditions of opening and accelerated closing. The valves also offer positive security against water hammer, through their practical operation as safety valves of large section.

When the laborious and painstaking efforts which characterize experimental work on European railways, with the certainty of achieving ultimate results before anything is permanently adopted, is borne in mind, it is quite evident that the Prussian State Railways and others interested are not blundering blindly into radical transformation of previous devices. The very fact of the Lentz valve application to the fastest express engines

on those railways affords food for thought, and certainly for speculation on the outcome. Whatever the developments may be, they will be awaited with unusual interest, as the correct interpretation of the valve gear problem is not the least important question with which railroads at large have to deal.

tions, except that the web part of the channel of the shell sections is curved outwardly while the corresponding part of the furnace sections is curved inwardly, or toward the fire.

The intermediate plates embraced by the flanges of the channel sections extend from the furnace to the shell and are provided with openings for the proper circulation of water. The intermediate plate serves the double function of stay

Locomotive Boilers.-Under date of May 23, 1910, the board received, through Secretary Moseley, of the Commission, a request to make an examination of an exploded boiler on the Pennsylvania Railroad to determine the cause of the explosion. In compliance with this request, Chairman Cooley proceeded to Altoona, Pa., and made an examination of the boiler. Through the courtesy of the officers of the Pennsylvania Railroad he was permitted to take portions of the ruptured sheets for the purpose of subjecting them to a chemical and microscopic test.

Under date of September 21, 1910, the board, through Secretary Moseley, of the Commission, received a request from Mr. W. F. Buck, superintendent of motive power of the Atchison, Topeka and Santa Fe Railway, to witness a test of an improved form of firebox which was conducted at Topeka, Kan., on September 26. The test was designed to demonstrate whether this particular form of firebox could withstand stresses which, in the ordinary form of firebox, in most cases produce ruptured sheets and result in socalled explosions. Mr. Ewald went to Topeka to witness this test. Mr. E. L. Gibbs, one of the Commission's safety appliance inspectors, also was present on behalf of the board.

The Jacobs-Shupert firebox is made up of channel, or U-shaped sections, bent to the desired form, placed flange to flange transversely of the furnace throughout its length. The sections are riveted together with a plate between the flange of adjacent sections. The shell of that part of the boiler embracing the furnace is built up of similar channel-shaped sec

*Extracts from third annual report of the Block Signal and Train Control Board to the Interstate Commerce Commission, dated November 22, 1910.-Continued from March, 1911, Magazine.

purpose the edges of the flanges can be calked against the ring, and it is possible also to calk the edges of the ring against the channel flanges on the furnace side. Without the ring the flange edges of the sections would come together and the calking could not be done effectively.

With this construction the flanges and stay sheets are not exposed directly to the heat of the furnace, and the curved parts of the sections, which are highly heated, are suspended, as it were, from the ring sections formed by the flanges and stay sheets.

The test demonstrated that with the crown sections of the firebox raised to a

temperature of 1,120 degrees Fahrenheit (the water being four and one-half inches below the crown sheet) the construction withstood safely a pressure of 220 pounds Under similar condiper square inch. tions a firebox of ordinary construction would probably have failed.

Mail Cranes. A number of mail-bag catching and delivering devices have been presented to the board for examination. In view of the fact that the Postoffice Department has for many years conducted tests of these devices on its own behalf, and as the practicability of such devices to meet the needs of the Railway Mail Service is a matter that must necessarily be determined by that department, the board, with the approval of the commission, consulted with the superintendent of the Railway Mail Service relative to an examination of such devices, in order that there might be no conflict between the board and the Postoffice Department and no duplication of work. With this object in view, it was agreed with the superintendent of the Railway Mail Service that the board's examination and report on such devices would be confined wholly to the question of safety in railway operation; and with this understanding the board agreed to

submit its reports on such devices to the superintendent of the Railway Mail Service, confining itself entirely to the question of safety.

On this understanding the board was informed that the Railway Mail Service was testing a device on the Chicago, Rock Island and Pacific Railroad between Omaha, Neb., and Davenport, Iowa, and the board was requested to examine this device from the standpoint of safety and report to the superintendent of the Railway Mail Service. Full information regarding the device was furnished by the superintendent and permits to enter postal cars for the purpose of examination were arranged for. Mr. Ewald was delegated to make this inspection, and he witnessed the operation of the device as installed on the Rock Island. His report to the board furnished the basis of a report which the board made to the superintendent of the Railway Mail Service covering the safety features of the device. Train-Dispatching System.-The board has examined a number of devices which are intended to be used as adjuncts to the train-order or dispatching system, and designed to render station operators less liable to forget or neglect to deliver or ders to train crews. While these devices in the hands of faithful and conscientious operators, striving to the best of their ability to avoid error, would probably serve a useful purpose in the handling of train orders under the timeinterval system, and to that extent can be recommended, it is important to bear in mind that they do not cure, and, indeed, do not profess to cure, all the dangers of the train-order system. The board regards all dispatching systems which depend on the use of clocks and watches, on minimum time intervals between trains, and on written orders of various forms transmitted by telegraph or telephone, to be read and comprehended or interpreted by trainmen, as being so far inferior to the block system or space interval that it is not disposed to recommend the use or extension of any such dispatching system in preference to the block system. In other words, the weaknesses of the dispatching system are so complicated and perplexing that the only comprehensive means of dealing with them is the adoption of the space interval or block system, and the board can not countenance any improvement in a single feature of the dispatching system

without at the same time emphasizing the fact that the system as a whole still remains defective.

A B C System.-The A B C system of block signaling, which has been in use on the Northern Pacific for about three years past, and an account of which was given in our last annual report, page 51, has been abandoned on all but one of the divisions where it was in use, and it is to be abandoned entirely. It was introduced on a short section of the line east of Spokane, Wash., in the autumn of 1907; and the success which attended its use on that section led to its extension to the whole of the division and subsequently to other divisions, making an aggregate length of 681 miles of road on which the system was worked. Following a change of officers of the operating department, it was discontinued on the division east of Livingston, Mont., February 27, 1910; and on the lines west of Cheney, Wash., it was discontinued in August. On the remaining divisions, Paradise to Cheney, 204 miles, the change is about to be made.

The interest which was taken in this system by railroad officers generally was largely due to the increased safety secured by means of it as compared with the method, common on single-track railroads, of conferring on trains the right to the road by means of time tables, dispatchers' orders, etc.; and it was in relation to the efficiency of the system as a means of safety-that is, of preventing collisions-that it was considered by this board. It appears, however, that its adoption on the Northern Pacific was largely because of the economy thereby secured in the movement of freight trains, and the reason given by the officers for going back to the old system is that, although in the use of the A B C system they secured the advantages expected, so far as freight trains were concerned, there was a disadvantage in that important fast passenger trains were delayed.

The board has not had opportunity to make a thorough inquiry concerning the situation since it was advised of this change; but a letter from an officer of the road indicates that this delay of passenger trains, together with some inconveniences when line wires were broken or otherwise unavailable for use, was the reason for changing.

As the movements of all trains are under the immediate direction of a dis