potential power contained in coal and other fuel into power, the steam boiler must be used. For this reason the steam boiler will always be with us.

The boiler has kept pace with other improvements. Some of the first resembled and were not much larger than a teakettle. These original teakettle affairs had arched bottoms, sloping sides and domelike tops. In all of the old original type of boilers the heat was applied from the outside. The first inside heat that might be termed such came when the first boilers were invented that contained one or more large flues for the hot gases to pass through. Later boilers were designed with smaller tubes for the return of the heat. As the engine was improved the demand for power increased and boilers were built to withstand a pressure of 60 to 70 pounds to the square inch. This was for a long time considered a dangerous pressure and has not been increased much in the common multi-tubular return flue boiler where the heat is applied below the shell.

For locomotive purposes it became necessary to design boilers that would withstand a pressure as high as 120 pounds, and for years this was considered the maximum for locomotive service. All the older locomotive men will remember how they used to hold down the scales to force the steam pressure up to 128 or 130 pounds when the chances were that they would "lay down" if they did not increase the pressure a few pounds. The older enginemen will not forget when the 16 and 17-inch cylinders came, and a maximum boiler pressure of 140 pounds was established. As long as the scales or "monkey tails" were in service the enginemen of that time took the chance of disrupting their boiler rather than double hills. With the introduction of the "pop," or safety valve, the scales disappeared and the practice of "holding her down" for a few pounds more had to be given up.

Locomotive boilers are of the horizontal multi-tubular class with internal firebox. At the present time there are five different types in general use-the

""extended

“wagon top,” “straight top,"

wagon top," "Belpaire," and "wide firebox." The extended wagon top, wide firebox and Belpaire are the later designs in locomotive boiler building and were introduced in the order named. In my first 20 years of locomotive work they were either "straight top double domed" or "wagon top single domed” boilers.

Special advantages are claimed for different patterns of boilers, which of course, are based on the service, kind of coal and water used. The extended wagon top was designed principally for more steam space. The wide firebox was invented by Wooten and was built for the purpose of burning "slack" or the refuse from the coal mines.

In the summer of 1881 the Northern Pacific purchased a number of Wooten firebox engines expecting to be able to effectually burn the lignite or "baby mine" coal which was found in large quantities in the bad lands of Dakota. These wide firebox engines proved a miserable failure in their attempt to burn the lignite, as did every other engine that was compelled to try to do business and burn that stuff.

I spent the summer of 1881 trying to get trains over the Dakota division of the N. P. with "baby mine" coal and alkali water, and my experience there was something fierce. The Brothers who were there before me and who remained in that company's service are deserving of something more than a pension in their old age, and should have a few extra strings on their harps when it comes their time to perform celestial duty.

I would like to see a cut of one of the N. P." dirt burners" in the columns of our JOURNAL, and wish it was possible for me to get a little history from the N. P. Brothers regarding the length of time those engines were kept in service and what final disposition was made of them.

The Belpaire boiler, or what might more properly be termed the Belpaire firebox, was the invention of Belpaire, a native of France. This construction of

firebox was adopted to have crown sheet and top of shell parallel and thereby have the staybolts at right angles to the sheets. The advantages claimed for the Belpaire firebox are that more steam and water space is created and that it gives the crown sheet a chance to expand and contract with less damage than when the crown sheet is supported by crown bars.

In the Belpaire firebox the top of shell can move in conformity with the crown sheet. I am not prepared to make any extravagant claims for the Belpaire firebox, as I have no data at hand that would aid me. I do claim, however, that the principles involved are good ones. For seven years I worked behind a Belpaire firebox and during that time I found no crown sheet leaks nor bulges, and if my choice was to be considered I would ask for that form of firebox.

In my talks with "boss" boilermakers I do not hear anything of importance against the Belpaire invention and yet this form of fire is but little used. Perhaps there are conditions which will not admit of the Belpaire construction in the larger and higher power type of locomotive boilers. As this article on boilers will be continued, I hope in the February number to give the views of some able boilermakers on the merits or otherwise of the Belpaire invention.

The tubes of locomotive boilers are usually made from sheet iron lap-welded together. Steel tubes are used which are drawn solid from the metal. Steel tubes can be made thinner than the iron and are in consequence of greater advantage for the reason that the thinner the tube the more readily the heat is conveyed to the water surrounding it, also more water space is created.

Tubes are generally two inches outside diameter; to decrease from that size will admit of more being used, which will increase the heating service, but complications then arise on account of their being easily stopped up.

In the old days of wood-burning locomotives, flues were made of copper with a cast iron thimble driven into firebox end to keep flue tight in sheet. In the

coal-burning engines of today copper ferrules are placed between the tube and sheet, which permits of expansion and calking without injury to the sheet.

In the present day types of boilers the greatest efficiency is required to meet the demand required by larger cylinders and higher speed. The limit in size has been reached on many lines where tunnels, bridges and buildings must be considered. Not many years ago the stack that was not five or six feet in length looked out of proportion to the boiler. Today if the stack is longer than an ordinary plug hat the boiler looks out of proportion to the stack. When the boiler and firebox limits are reached more and smaller tubes are inserted in order that the necessary amount of heating surface can be created. The term heating surface includes all surfaces in the firebox and boiler that are exposed to the heat. In figuring the heating surface the crown, back and side sheets and tubes are considered. The front or flue sheet is not included in the measurements. Of the surfaces exposed to the heat the crown sheet is the most effective, the other firebox sheets next, the tubes last.

Experiments made some years ago showed three times as much heat per square foot in the firebox as was shown in the firebox end of tubes, and more than twelve times as great as shown in that portion of the tubes at the front or smoke arch end of boiler.

The efficiency of the heating surface is governed largely by boiler conditions. Where scale and mud prevent the heat reaching the water the boiler cannot evaporate the proper amount of water. The heating surface of a boiler is called direct and indirect. The firebox measurements are called the direct, while tubes and front tube sheets are figured as the indirect heating surfaces.

In designing a boiler heating surface is proportioned in accordance with the piston displacement. Experience has taught that the number of square feet of heating surface should be about 500 times the piston displacement in cubic feetbut one piston to be counted. To find the

amount of heating surface for a modern 20 x 26 bituminous coal burner the following method is used: Multiply the diameter of the piston by itself and the stroke in inches; then multiply the product by the decimal .24. Example: 20 x 20 x 26=10400 x .24-2496 feet of heating surface, which would be considered nearly right. However, this ratio of heating surface to piston displacement is being increased. The tax put upon boilers for larger air pumping capacity, heating the trains by steam and running a motor for the electric headlight calls for a more rapid evaporation of water. In figuring out the right proportion of grate surface to heating surface, in engines burning soft coal, about one square foot of grate to 70 square feet of heating surface is generally considered sufficient. To find the great surface needed for the 2496 feet of heating surface given for the 20 x 26 cylinder locomotive, you would divide 2496 by 70, which would give about 35% square feet of grate surface. Grate surface is varied on account of a difference in the kind of coal used. Difference in opinion by the mechanical "push" causes quite a variation in the amount allowed grate as compared with heating surface.

In the past year a record of new locomotives shows as follows: B. & O. 2-8-0 have 49.1 square feet of heating to one of grate surface; Wabash 4-6-0 have 83.4 heating to one of grate; M. K. & T. 4-6-0 92.8 heating to one of grate; Monon 4-6-2 66 to 1. This is a record of only four of the soft coal burners illustrated during 1906. Note the difference in amount of grate surface given.

In the years gone by it was the universal belief that most of the boiler explosions were caused by low water, or some mysterious influence. When boilers exploded it was generally charged to the engineer who, as a rule, went up and out with his boiler. Of late years thorough tests have been made and the low water theory is now very seldom given as the cause for boiler explosions.

Some years ago when the United States Government was making boiler tests Dr.

Coleman Sellers stood by the boiler after furnace sheets were heated red hot. He held a piece of wood against the boiler to convince himself that sheets were hot enough to char the wood. He did not leave the boiler when cold water was turned into it and found that the only effect was that sheets shrunk so that the boiler leaked all pressure away.

The Pennsylvania Railroad Company made tests years ago along the same lines as given above. A locomotive that was condemned to be "scrapped" was run out on a side track in the woods and experiments made upon it. The plan was to fill the boiler with water, raise a high pressure of steam, then run off the water until crown sheet was exposed; then after crown sheet became hot, pump in cold water. In the first experiment the boiler blew up before they left off any of the water. They tried again with another scrap heap. The water was drawn off and after waiting long enough for the crown sheet to get red hot, they forced in a supply of water by means of a fire engine and nothing happened except that the seams leaked. Experiments along these lines were made repeatedly with exactly the same results.

Boiler explosions are always due to the fact that some part of the boiler is too weak to withstand the pressure. The design of the boiler may be defective, or there may be defects in the material or work. The shell may be weakened by corrosion, pitting and grooving. Excessive pressure may be created by safety valves not lifting when they should; crown sheet may have been weakened by allowing water to get too low. It is claimed that weak boilers have exploded by the sudden opening or closing of the throttle.

There may be other reasons why boilers explode, but the evidence is with us that when boilers are properly designed, well made, given proper care, regularly inspected, repaired when they should be, and taken from the service before their age makes them dangerous, the danger from explosions is reduced to the mini

mum.

Results - With Engines Pooled.

FT. SCOTT, KANS., Dec. 12, 1906. EDITOR JOURNAL: I noticed on page 1055 of the December JOURNAL an article written by Bro. J. A. Talty. He says in part: "When engines are pooled enginemen become careless and do not take the interest in maintaining locomotives they do when regularly assigned.”

It seems to be a prevailing opinion among railroad officials that engineers are to blame for the poorer showing made by pooled engines. Nothing could be farther from the real facts. Let us look into the question and see how much the engineer really is to blame.

First. Do we run pooled engines faster or work them harder than regular assigned ones? Surely not. Pooled engines, as a rule, are not in shape to stand the harder rapping.

Second. Does the engineer neglect to

properly oil and inspect the pooled engine before starting out? We all know that a pooled engine gets a most careful oiling and inspecting before starting, the engineer not taking any unnecessary chances in making trouble for himself in the way of heated bearings, loose nuts, etc.

Third. Does the engineer neglect to report the necessary work to be done on engine at end of the trip? Well, I rather guess not. My experience and observation has been that the average engineer reports from three to five times as much work on pooled engines than on a regular assigned engine. What makes this necessary? Simply this: The work reported on a regular assigned engine is done and usually in first-class shape. On a pooled engine it is either not done at all or is done in a very inferior manner. Instances have come under my notice where the engineer on his arrival at terminal reported enough work on the engine to keep her tied up for at least ten hours, yet I have seen this same engine leaving town on a "drag" in less than three hours after arrival. Perhaps they were short of power. Admitted. Then why blame the engineer for conditions over which he has no control?

In making ordinary running repairs on pooled engines they figure that any kind of an old job will do. If it happens to be a regular assigned engine it is figured that Billy So and So runs that engine and if a good job is not done you certainly will hear from him, and perhaps from the old man too.

Consequently, pooled engines go to pieces quicker and do not make the good showing that regularly assigned ones do.

There is another matter that is affect

ing the staying qualities of engines that

lies with the builder, cheaper material being used and less care taken in construction; also an increased steam pressure. We had an illustration of this recently when a large locomotive works in the United States sold new engines to Japan. These engines were new and supposed to be in first-class shape for service, yet the Japanese complained that they had to put them all through the back shop before

placing them in service. They particularly criticised the careless work done on the boilers.

GRAND RAPIDS, MICH., Dec. 4, 1906. EDITOR JOURNAL: In a recent issue of the JOURNAL I wrote an article, "Do Engines Slip with Steam Shut Off?" It was claimed by one of our oldest engineers that such was the case with his engine. At first, the idea seemed along the line of being ridiculous. However, he all his fireman strongly maintained that such was the case, and that it was almost a daily occurrence. Through their repeated assertions that such was the case I decided to give the matter some thought. On investigation, I found the slipping took place when the steam was shut off and the brakes applied to make the station stop.

My personal experience with this engine was that frequently the driver brake would not apply when setting the train brakes. The schedule was very fast-requiring a speed of 60 miles per hour between stations, The tire on the driving

wheels was very hard. The counterbalance in the wheels was perfect. My conclusion was that when the brake was being applied on the train, the drive brakes did not apply the speed of the train was being checked while the speed of the driving wheels did not check on account of the driver brake not applying. The result was that the drivers would slip for a short distance until the momentum was checked.

LEROY A. OGDEN, Div. 286.

Electrification on the Erie. Westinghouse, Church, Kerr & Co. have been authorized to prepare estimates for the complete electrification of the Rochester division of the Erie Railroad between Rochester and Corning, N. Y. Ninety-five miles electification of the 24 miles of this division lying between Rochester and Avon and Avon and Mt. Morris was begun last summer and is now nearly finished. The installation is single-phase, similar to that which is being placed on the New York approach of the New Haven road. Power will be supplied from the single sub-station to be located at Avon, N. Y., which is about 19 miles from Rochester and 15 from Mt. Morris. The power is to be derived from the lines of the Niagara, Lockport & Ontario Power Co., which receives the current generated at the new station of the Ontario Power Co. at Niagara Falls, and it now transmitting it at 60,000 volts as far east as Syracuse, where trolley cars of the local electric railway system receive it. This long transmission line, which is being constructed in duplicate, crosses the Erie Railroad at Mortimer, about five miles south of Rochester, and from that point the power company is building a branch line about 14 miles long, which is to supply the sub-station at Avon.

The sub-station building, of brick and reinforced concrete, is now nearly completed, and the electrical apparatus which it is to contain is being shipped from Pittsburg. The equipment of this substation is extremely simple, consists of three 750-k.w. transformers of the oil

insulated, water-cooled type, which transforms 60,000-volt three-phase current down to a 11,000-volt single-phase current

Difficult problems were encountered at Avon and Rochester in supporting the trolley wires, over the tracks through the railroad yards, and a new style of overhead span wire construction has been designed to overcome the difficulty of carrying such heavy trolley construction where it is impossible to place poles between tracks. In place of the steel bridges used for this purpose on the New Haven road a system of "tripartite" steel poles and double spans have been adopted, and is believed by the Erie to be fully as effective a type of construction as the other to meet the conditions; to be far cheaper, and much quicker to erect.

The

Electric equipment is being placed in six passenger coaches of the interurban type. Three coaches were built by the St. Louis Car Company, being 54 ft. long and seat 56 persons. The equipment consists of four 100-h.p. motors and Westinghouse electro-pneumatic control. cars are designed for a maximum speed of from 45 to 50 miles per hour and will be able to haul one trailer under any of the conditions of service that are likely to prevail. The trolleys are of the Pantagraph type, consisting of a horizontal crossbar, which makes the contact with the overhead wire, and is raised or lowered by a light jointed framework mounted on top of the car, controlled by air pressure, and making sliding instead of rolling contact.

The schedule now being prepared provides for an hourly service in each direction between Rochester and Mt. Morris.Railway Gazette.

The Engine Crew.

On the highest authority we have it in effect that no man can work for two masters. Yet the engine crew gets orders from the master mechanic, the roundhouse foreman (not to mention the call boy), the superintendent, the trainmaster, the dispatcher, the conductor, and indirectly, the traveling engineer,