[quote user="BaltACD"]
And Death Valley Scotty was nowhere around!
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No, Death Valley Scotty wasn't around, but I believe Black Forest Fritzie was on board!
Soryy, couldn't resist!
The model on display at the Sprague Building is of the Siemans and Halsk car. Colors are deep purple-brown and cream.
Never too old to have a happy childhood!
LECTURE AT THE NEW YORK ELECTRICAL SOCIETY.
The 251st meeting of the New York Electrical Society was held May 24. Mr. Charles A. Mudge, formerly chief engineer of the railway department of the Allgemeine Electricitats Gesellschaft, Berlin, who took part in the tests on the famous Berlin-Zossen road, lectured on "High-Speed, Long-Distance Electric Traction." Mr. Mudge stated briefly the conditions existing in high-speed traction about six years ago, when the plans for these extraordinary experiments were formulated by Messrs. Ratherau and Schweiger. Continuing, he said, in part:
As is generally known, these tests were made under the direction of a company organized for the special purpose, and known as the "Studiengesellschaft für Elektrischc Schnellbahnen."
The objects of the tests were to make a study of many of the heretofore incompletely, and in some cases, wholly unknown factors entering into electric traction at speeds never before attempted, such as collecting current at high voltages, traction and air resistances, best design of trolleys, motors, transformers, brake gears and trucks, the power required to run at high speeds, the details entering into the construction of the permanent way, and the collection of other data in order to calculate costs of future installations.
The track selected for the experiments parallels the main line running south from Berlin toward Dresden, and is used by the Ministry of War for giving instruction to the railway corps of the army. The car barn was located five miles from Berlin, at Marionfelde, where the tests were, started toward Zossen, fourteen and one-half miles distant, over a track having only two decided curves, of one and one-fourth miles in radius each. The first one occurred three and one-eighth miles from the car barn, the second, seven miles further on, leaving four and three-eighths miles to Zossen. This practically divided the line into three parts - four miles at each end for acceleration, and seven miles for running in the middle - with almost no grades; conditions about ideal for the tests contemplated.
Power was supplied from a central station seven miles distant, to a cablehouse along the line a little over one-half a mile from the car barn, where it was connected directly to the trolley wires through automatic circuit-interrupting devices.
The apparatus installed in the Allgemeine car differed quite materially from that installed in the Siemens & Halske car, and my remarks will refer only to the apparatus used in the Allgemeine car.
The car body was sixty-nine feet long and nine and one-fourth feet wide, and was divided into three compartments by a so-called machine room, twelve feet long in the middle, which contained the starting rheostat and high-potential switches, and was not allowed to be occupied while current was on. The other two compartments were utilized for measuring instruments and for passengers, and were connected by a narrow passage through the machine room.
On either side of the machine room underneath the car floor the transformers were fastened. The six-wheel trucks were spaced forty-three feet seven and five-eighths inches from centres, and the forty-nine and three-sixteenths-inch wheels had a base of six feet three inches, which was increased later to eight feet two and one-half inches.
Three-phase current was used, and the highest recorded voltage in the car during any test was 14,150. The current collectors were of the sliding bow form, six in number, and placed in groups of three on each end of the car, two bows working in parallel on each [wire].
The weight of the complete car with fifty passengers was 100 tons (2,000 pounds to the ton), which was increased four tons in the last year of the tests by alterations necessary to accommodate the new trucks and by balancing weights.
The first year, September, October and November, 1901, was what might be termed a 'try-out' period. The entire installation, with the exception of the permanent way, being new, it was necessarily handled with greater caution than it would have been if the apparatus had been of a more standardized construction. Before the car was taken from the works all apparatus was thoroughly tested, and for this purpose a stationary bed plate, having four run wheels, was arranged under each truck, the wheels on the bed plate having profiles similar to rails, and made wide enough for brake straps of dynamometers.
After all apparatus had been given as thorough a shop test as possible, the car was hauled approximately 500 miles by a steam locomotive in order to loosen it up. After this many different runs were made, the maximium speed attained during this year's test being 100 miles per hour.
The second year of the tests, September, October and November, 1902, was occupied mainly in determining the train resistance at different speeds, in measuring the power required for different loads and speeds, in determining the losses to the transmission line, in collecting the necessary braking data for computing the coefficients of friction for different speeds, and in determining the alterations necessary to be made in the car and the permanent way, to allow us to run up to 125 miles per hour.
These tests were conducted up to a speed of only seventy-five miles per hour, as the observations of the previous year showed that the permanent way would not stand much higher speeds. To determine the train resistance as well as the energy absorbed in running the car a distance of four miles, starting at the car barn, was very carefully measured, and all curves, grades and levels were absolutely fixed. This made it possible to correct the observed data so accurately that the recorded results in this year's report are of the greatest value.
The brake tests made in this year were not as satisfactory as those in the following year, on account of the complicated brake rigging used, which did not allow of easy adjustment, and which I will not therefore attempt to analyze.
Suffice to say, that the maximum retardation of two miles per hour per second was recorded at seventy miles per hour, with a total brake pressure equal to 155 per cent of the weight of the car. At the conclusion of the tests this year it was found necessary to build new trucks with a two-foot longer wheel base, and to support the car body on the truck frame at some distance from the centre pin. Also to flexibly support the centre pin in the truck, thereby allowing the car body to have a movement of about one inch on each side of the truck centre independent of it, and in a line at right angles to the track. In order to observe the action of the springs and their connecting levers, it was decided to place them on the outside of the frame of the truck. The tests this year were of value in showing what alterations in the car and permanent way were necessary in order to be able to run at higher speeds.
Data of very great value were secured on the much discussed question of air resistance, and although the formula may not be straightened out to suit everybody, we know positively that if we run our car, for instance, fifty miles per hour we can expect a maximum air pressure of about seven pounds per square foot at the front of it: and if we double the speed we will get four times this pressure, and if we triple the speed we will run into trouble and get nine times this pressure. If we shape the nose of our car properly we will be able to reduce these figures ten per cent. Also if we run our 100-ton car fifty miles per hour on a level track without paying much attention how the front of it is shaped, it will take about 150 horse-power. When we double the speed it will take six times this amount of power; but if we attempt to triple the speed, i.e., to run at 150 miles per hour, we would have to supply about eighteen times the amount of power it takes to run at fifty miles per hour.
As had been anticipated, the new truck used this year, with its greater wheel base, worked much more satisfactorily than the old one. The feeling that the car body was being carried along by something that knew its business came to all who took part in the tests, and the sense of security when running at high speeds around curves was a comfortable one.
That was due not only to better designed! trucks, and the manner in which the car body was supported on them, but also to the excellent service given by the new eighty-two and one-half-pound rails, the closer-spaced ties, and the more substantial ballast. At the very outset of the tests considerable difference was noticed in the behavior of the car when running above or below 100 miles per hour. At about this speed the car seemed to take on a swinging lateral motion, which at times became so pronounced that it endangered the overhead work, and created a feeling of insecurity in the passengers.
The cause of this was found to be the unsymmetrical disposition of the motors and transformers on the car. This was ascertained by taking the weight of the car under each wheel, which showed a maximum variation of one and one-half tons in some cases.
This was counteracted by placing weights along the floor of the car, four and one-half feet from its centre line at each truck, after which no further vibration was noticed, even up to the highest speeds, and the car ran as smoothly as our Pullmans.
The working of the trolleys was satisfactory after they had been properly adjusted, but it was evident that a more substantial construction would have to be adopted on installations where schedule speeds must be adhered to.
The enormous brake pressures needed at high speeds to give a comparatively low retardation, show very plainly that our familiar friend, the coefficient of friction, is not going to help us in the same proportion that he is doing at present; but if he doesn't electrical means will most likely help us out. For instance, it was found to take about seven-eighths of a mile to stop the car when running 110 miles per hour, the initial brake pressure being 150 per cent of the weight of the car. If we had some means of keeping the retardation constant, we could have stopped the car in three-fourths of a mile by using the same pressures. Under the most favorable conditions the car could not have been stopped in less than one-half mile when running at 110 miles per hour, which would require a retardation of three and one-fourth mile per hour per second, which is about the limit of braking with this type of braking apparatus. The preeminent value of the braking system employed lay in the fact that it never failed in its operation during all the tests made, and the feeling of security which its absolute reliability inspired.
Basing our ideas upon some of the observations and experiences gained in these tests, we would make use of the following points in approaching a similar problem:
(1) Keep the car body as near the rails as possible.
(2) Arrange all heavy pieces of apparatus so that their centres of gravity lie in the centre of the car, or symmetrically placed to it, and as near the earth as possible.
(3) All apparatus mounted above the car floor should be as light as their design will permit.
(4) Make the overhead trolley contact above the car, in preference to the side of the car.
(5) Support the motors flexibly on the axles of the trucks.
(6) Give the front end of the car a wedge shape.
(7) Support the car body on the truck frame at some distance from the centre bolt, and allow it a flexibility in a line at right angles to the track, independent of the truck.
(8) Make the total wheel base of the truck of ample dimensions, and not less than twenty per cent of the length of the car.
(9) Build the road as straight as possible, and where more than one track is used make them further apart than our present practice would suggest.
(10) On curves, make the approaches of the elevated side of the track longer than usual.
If it were possible to have the wheels along the sides of our cars and the rails between the floor and roof lines, we should have very comfortable traveling. Any condition approaching this, as by keeping the car body near the rails, would share in the benefits thus derived.
A German engineer of considerable prominence has advocated lowering the floor of the car between the trucks, in order to make it ride steadier, utilizing the space above the trucks for second and third-class passengers, or for freight and baggage. Although this might be too radical a change in designs of our standard practice, and would not harmonize as well with conditions here as with those abroad, it would undoubtedly give good results. That all apparatus should be symmetrically mounted in relation to the centre line of the car was very evident as we approached the 100-mile-per-hour figure. Our motors were mounted slightly out of the centre line of the truck, and it was found necessary to use 275 pounds per motor to counteract this.
The transformers, which weighed three and one-half tons each, were mounted on either side of the centre line of the car body just behind each truck; and a line connecting their centres of gravity did not coincide either with the transverse or the longitudinal centre line of the car. This gave rise to a torsional movement which produced a dangerous swinging of the car when running above the speed referred to, which was overcome by placing weights of about one ton each on the side opposite to that to which the transformer was mounted. The fact was thus confirmed that heavy pieces of apparatus should be mounted in the centre lines of the cars for high-speed service, as they run smoothly only when their weight is equally distributed upon the wheels.
All apparatus above the car floor should be light. This applies particularly to the trolley construction. If the trolley for high-speed work is to be of a light construction, which is the tendency of most designs abroad, particular attention must be given to the form of the exposed surfaces, on account of the high air pressure, and means must be applied to counteract it. When the current is collected at the side of the car, as in these experiments, any slight swaying of the car is at once felt by the trolley, and the higher the current collectors are placed from the ground the greater is this disturbance. Also the trolley wires as placed in these tests were very sensitive to cross winds, and even to the slight pressure of the sliding bow against them, necessitating spacing the supporting poles closer together than they were originally placed, and stretching the wires themselves with very high tensions.
If the motors are direct-connected to the axles, a part at least, of their weight should be flexibly connected to it. Motors of this power - 250-horse-power normal rating - run into weight, and, both on account of the permanent way and the truck, as much of their weight as is possible should be flexibly supported on the axles. This flexibility need not be great, and can be through the medium of heavy springs. There is a certain oscillation given to all the parts on a car moving at such high speeds, and it often occurs, through the unevenness of the road-bed, of slight inequalities in the rails, or the motion of the car itself, that a certain oscillation of a heavy piece of apparatus will be met out of step. For instance, the motor will be going down just as a part of the rail is coming up and a severe blow will be the result. A little flexibility of these parts will greatly reduce the force of this blow. At speeds over 100 miles per hour it very often seems as if the rolling friction were taking a rest, and that we were actually floating for short distances, after which we notice very distinctly that gravity has not forsaken us, and we can almost hear the rails groan under their extra burden.
It is at such times that the flexibility of the apparatus is mostly needed; not so much when we pass over rail joints or frogs, as the car doesn't take much notice of them and is far beyond before their effects could be felt; but just at those moments when the apparatus seems to be furthest out of synchronism with the car.
Since it is impossible to build an absolutely level and straight track, we can help conditions very much, as well as increase the comfort of passengers, by having heavy pieces of apparatus flexibly supported in the car.
Giving the car a wedge-shaped construction may not be possible when using the vestibuled type with multiple unit control, and no definite end relation, in which case it may be advisable to have a portable wedge-shaped engineer's cab on wheels, capable of being quickly attached to the front of the car in making up the train.
We found that it was a very good thing to hold the car body firmly to the truck frame at points equally distant from the centre pin, also to allow it a movement independent of the truck, parallel with the axles. The trucks take curves much more quickly than the heavy car body, which requires a certain amount of time to swing it nut of its straight line path, and should not be attempted too rapidly.
It should not receive a blow to turn its nose in the new direction, but a gradually increasing pressure until it is turned out of its former course. This was very well accomplished by the centre pin bearing being mounted flexibly in the truck. The pin was held in its middle position by one and one-half tons pressure, and could be moved out of this position for one and three-sixteenths inches to its furthest limit, by the addition of about two and three-quarters tons pressure. This had the effect of swinging the car body more gradually into the direction taken by the trucks, and the shock was considerably less than that experienced with the trucks used in the first year's tests.
If we build our roads with few curves, we might as well take full advantage of the fact, and make our wheel base long. The thirty per cent increase of base in the truck used in the last year's tests was a noticeable improvement over that used in the previous tests. With a greater distance between wheels we have a better chance to equalize the weights upon the axles, since the lever arms and springs between them may be made longer and consequently more sensitive and easier to adjust. In three-axle trucks the motors will most likely always be mounted on the outside axles, making it necessary to carry a greater percentage of the weight of the car body on the middle axle, than is carried on the outside ones.
As this weight fluctuates considerably this fact must not be overlooked in designing the equalizing lever arms of the truck; as otherwise the load will be unequally distributed on the axles and possibly disturb the smooth running of the car.
In passing stations at 125 miles per hour it was not possible to recognize persons standing upon the platforms, and only those at a distance of fifty feet and over could be approximately identified. On dark and rainy days it was quite impossible to read signals at this speed, except when of large dimensions or of very pronounced color.
This would suggest placing the signals in the car itself, operated electrically, either by direct contact or through inductive means. Such a system was tried at Zossen and worked perfectly, even at the highest speeeds.
An insulated piece of angle iron was placed alongside of the rail, it and the rail constituting two poles of an electric circuit. As the car passed over this section contact was made with the angle iron by a brush which led current through a magnet in the car, releasing a spring and allowing a disc to fall in front of the motorman. the circuit being completed through the wheel.
A system on similar lines could easily be arranged to ring different bells, or to
operate different colored discs in the engineer's cab, thus relieving him of the strain upon the eyes caused by passing so many objects which naturally distract his attention.
In all the runs, of which over 300 were made, no difficulties were met with, or even suggested, that the skill of the engineer did not or could not overcome, and this great triumph, in a branch of industry which has done more than any other to lift the human race to a higher degree of intelligence, should serve as a stimulus to us, who are anxious to have trains in regular service running at this, the highest speed ever attained by any device used for human transportation, 131 miles an hour.
DISCUSSION.
Mr. Sprague - It seems to me that there are two questions suggested by the Zossen experiments:
(1) To what extent will the commercial possibilities warrant speeds anything like those attained?
(2) Assuming that for long distances alternating current be used, shall it be by the polyphase method as at Zossen, or in a single-phase development?
One thing must strike everyone who has followed Mr. Mudge's most interesting description, and that is the extraordinary difficulties which had to be met, and the great increase of powers as the speed approached the higher marks. My own impression is, taking into account all the practical conditions surrounding trunkline construction and operation, a maximum speed of about one hundred miles an hour is all we can reasonably, for a time, at least, try to reach. Not that cars can not be operated at higher speeds; but the difficulties which must always stand in the way when we take into account all the essentials of trunk-line operation, seem as yet to hardly warrant the commercial use of such speeds. This is a feeling which I have had for a number of years, and I believe it is one which is generally shared by both electrical, engineers and steam road operators whenever they have fully studied the matter.
These conclusions, of course, do not vitiate or belittle in any sense the importance of the experiments which have been made, because, in order to operate even at 100 miles an hour as a maximum it is desirable to make trials at much higher speeds, not only to develop weaknesses of apparatus, but to clearly indicate the practical working difficulties and limitations which confront the engineer.
Mr. Mailloux - It seems to me that these tests prove all that was intended. In regard to the selection of systems when it comes to traveling over fifty miles an hour electrically, while it seems as though we should use some alternating system, I am not prepared to say which should be used. The single-phase has not yet been developed to sizes which will do what the large polyphase motors can do. Before we can authoritatively say what would be the best method, further experimentation will be required. I do not think that that point will be reached immediately. The experiments now being made on the New York Central and Pennsylvania roads will give us some valuable data. I am not prepared to say, and I don't think any person is, that they will bring about any real general solution. They are, in reality, what mathematicians term "particular solution." We have something to learn before the electrification of steam roads in general is an accomplished fact. We shall have to proceed gently. I do not wish to be understood as being pessimistic; I believe it is going to come; but by evolution rather than by revolution; not to-morrow, or in ten days, nor, possibly, in ten years. I believe there will still be steam locomotives twenty-five years from now.
Mr. Sprague - I quite agree with the general statements which have been so clearly made by Mr. Mailloux. We are not on the eve of the general conversion of steam-operated roads. It is interesting to note that some of the difficulties met with on the Zossen line at high speeds were encountered in the earlier tests on this locomotive. Notwithstanding the fact that it had leading trucks, there was a distinct "noseing," caused by lateral sway, which was periodic, i.e., corresponding to the length of the rails, and resulting in some displacement at thirty feet intervals. It was thought, at one time, that possibly the low centre of gravity was the cause of this; but this, apparently, did not prove to be the case, for, by using side springs, and subsequently, in addition, friction plates, to retard the free action between the body of the locomotive and its pilot trucks, this "noseing" was made to entirely disappear, even when traveling at the rate of eighty-two miles an hour. Had the potential been raised I have no doubt that speeds of between ninety and 100 miles an hour could have been easily made.
Speaking, however, of the general problem, we must bear in mind that what is being done in New York relates to congested terminal operation, and there are many local conditions which have dictated the use of electricity without necessarily putting it on all points on a directly competitive basis with steam operation. One of the earliest applications of electrical operation in miscellaneous roads is likely to be due to the recognition of the fact that in many cases the concentration of grades and electrical operation, in whole or in part, at such grades, may prove cheaper than the making of costly detours. In such cases, both continuous and alternating-current motors can be used, and which shall be the better is a matter to be decided bv local conditions. In spite of the admirable work which has been done abroad with the polyphase system, and granted its possible desirability in certain special cases, I can not but feel that, speaking generally, the multiplicity of conductors will stand as a bar to any general application to trunk-line service, and that the later developments in single-phase operation, offer, on the whole, more promise of final adoption, where alternating currents are used.
Mr. Shepard - We have a locomotive in operation at East Pittsburg, upon a specially equipped track, about four miles long. We last week put this locomotive in operation, pulling a fifty-car freight train, for the benefit of the visiting members of the International Railway Congress. This locomotive is designed for the heaviest work. Its weight is 135 tons, its capacity 1,600 horse-power, the maximum drawbar pull being 80,000 pounds. This has been registered on the tests already made. The overhead construction is the catenary type and the voltage in use is 6,600. The control of this is by induction regulator. This is quite the ideal control for such service. The tests demonstrate fully the practicability of the single-phase motor of this capacity. The results were fully up to expectations. The tests seem to show that this type of locomotive will find its field in heavy service where concentrated powers are required, as, for instance, on pusher grades, which under steam service are most expensive to operate. In order to secure concentrated power with electrical operation the track conditions need be no more severe than for comparatively light steam locomotives - this by reason of the facility for distribution of the motive power over different axles. I agree with Mr. Mailloux and Mr. Sprague that the adoption of electricity on steam railroads will be gradual; at first, in such special applications as this locomotive is fitted to meet, and such terminal propositions as local conditions determine; and, ultimately, the expansion of these installations will be quite readily accomplished where the high-voltage single-phase system is used.
The other car by Siemens & Halske. For more info see online book, The Berlin-Zossen Electric Railway Tests of 1903...
http://books.google.com/books?jtp=i&id=43k5AAAAMAAJ&output=html_text
This may have been that experimental German electrification that Juniata filled us in on with a power car coach with horizonatally tapered ends, and three side pantographs contacting three wires for a three-phase ac electrification/ A model of the equipment can be seen at the Sprague building, Shore Line Trolley Museum, River Street East Haven. The beautiful about half-scale model once belonged to Frank J. Sprague.
the AGV went 370-something
Samuel A. Kelly
I can draw pictures with my keyboard!
-------- ( It's a worm)
The highest speed ever attained on a railway-131 miles an hour - was made by an electric locomotive in 1903.
-Wilmington Morning Star.
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