Duisburg museumsvogn til Norge

[ferrovialist]

Hello,

Vilken var världens första ledvagn? Byggdes den i USA?(...)

Yes. According to an article by Jury Koffman the first articulated tramcar in the world was built in Boston in 1912. They were rebuilt from two four-wheel cars to what is know in English and "two-rooms-and-a-bath cars". The Gotha G4 probably is the best know example of that.

The first articulated tramcars with a central bogie were built in Milwaukee in about 1920/21. These were also rebuilds, in this case from two bogie cars. There was a new-built three-section car in Detroit, built in 1924: http://www.detroittransithistory.info/D ... etcar.html. As far as I could work out the first all-new two-section car in the USA was built for Cleveland in 1928. However, it appears that all of these used a different type of central bogie to the Harkortwagen.

What do we learn from this? The Harkortwagen is the first type of tramcar in the world using the Jakobs bogie which was later used under all Düwag articulated tramcars which were built in thousands (including those built under licence) from 1956 onwards. It is also the oldest surviving articulated tramcar in the world.

With this background I trust you will understand why most people doubt that the best possible solution for this tramcar is to be owned by a company in Norway and to be away from public view. Also, a spokesman from DVG said in a TV interview today that for them the car was not more than scrap, suggesting a very low purchasing price.

I also wonder, if DVG and even more so Daimex are doing themselves a favour. I am not entirely sure if Daimex know what they really get. Either way, I doubt that it is a commercially wise decision for them. Those people in the rail industry with both knowledge and some sense or morale might see them as either utterly stupid or as the greedy idiots that took away an important historic item from its native country and from public view. Herr Kühn might be regarded as a eccentric and egoistic wealthy collector who wants a treasure for himself and himself only.

Regards

Christoph

Actually there was an experiment with an articulated tram far earlier, in Cleveland, Ohio, in 1893! It was built by the same principle as the Boston articulated tram of 1912, as well as the Göteborg "Två rum och kök" trams ten years later. However, the Cleveland experiment seems to have disappeared soon after it was presented:



I think you will agree with me that this is extremely modern looking for 1893. And some of you may be reluctant to believe it, as European trams mainly did not have closed vestibules before the 20th century. Another modern feature of the Cleveland artic was that it had electric push-button stop signals. An article series on this tram and other early artics appeared in Modern Tramway in 1966.

Roy B.

[Harald]

Jakobs patent comprised bogies both with one common pivot for the two bodies and with separate pivots. However, an essential part was that the two bodies could move indepently including skewing movement. If I'm not mistaken, that is not possible with the Düwag articulation. Thus it's not a jakobs bogie. It should be noted that there is a common misunderstanding, especially in english speaking countries, that any bogie placed between two bodies is a jakobs bogie, but strictly speaking that is not correct.

My apologies for bringing this up late, I just came to read Harald's comment:

The Duewag articulated tram is often referred to as an example of use of the Jakobs (Jacobs) bogie principle, like in this Wikipedia article:
https://de.wikipedia.org/wiki/Jakobs-Drehgestell

What Wiki says must not always be true, but in this case I think it is. The important part of Wilhelm Jakobs’ patent of 1901 is that one single bogie supports two different carbodies. How the bodies are supported should be of less significance. Over the years we have seen two separated pivots (and rollers), pivots on top of each other at the bogie centre, slewing rings, or just mounted on beams which are able to slide, or supported by air suspension.

You seem to define the Jakobs bogie by the ability for each body to move independently. And yes I agree to that point. But then you say that this is not the case with the Duewag articulated tram. But it is, and it would be impossible for the tram to move from a straight track into a curve if each carbody could not move independently from the bogie. I know the SL79 Duewag car of Oslo by detail, and can describe it like this: In the central bogie there two separate slewing rings (a slewing ring is like giant ball bearing), one slightly smaller than the other, and both placed in the centre of the bogie. The top of one slewing ring supports one of the carbodies, the top of the other supports the other body. Thus they can move as if they had pivots on top of each other at the bogie centre.

According to the Wiki article the first successful use of the Jakobs’ patent was on the “Fliegende Hamburger” high speed train in 1932. I don’t know the criteria for “successful”, but the 1926 Harkort tram of Duisburg did use the Jakobs’ principle, also some suburban trains in Germany by 1927. But they were not the first, the same principle was used on a tramcar in Milwaukee in 1921, and I would not be surprised to see even older experiments.

Roy B.

There is a link to the patent in Wikipedia. If one reeds and understands the patent, it is obvious that the Duewag articulation is not an implementation of Jakobs patent. In the patent claim it is stated that independent movement is possible around the vertical axis as well as both the horisontal axes. As you describe the SL79 articulation independent movement is possible only around two axes, the vertical and one horisontal but not around the horisontal axis along the car. The two rectangles below picture the two carbodies seen from one end. A movement as in the figure is possible accordning to Jakobs patent, but is not possible with the SL79 (or M21) articulation.

[ferrovialist]

Jakobs patent comprised bogies both with one common pivot for the two bodies and with separate pivots. However, an essential part was that the two bodies could move indepently including skewing movement. If I'm not mistaken, that is not possible with the Düwag articulation. Thus it's not a jakobs bogie. It should be noted that there is a common misunderstanding, especially in english speaking countries, that any bogie placed between two bodies is a jakobs bogie, but strictly speaking that is not correct.

My apologies for bringing this up late, I just came to read Harald's comment:

The Duewag articulated tram is often referred to as an example of use of the Jakobs (Jacobs) bogie principle, like in this Wikipedia article:
https://de.wikipedia.org/wiki/Jakobs-Drehgestell

What Wiki says must not always be true, but in this case I think it is. The important part of Wilhelm Jakobs’ patent of 1901 is that one single bogie supports two different carbodies. How the bodies are supported should be of less significance. Over the years we have seen two separated pivots (and rollers), pivots on top of each other at the bogie centre, slewing rings, or just mounted on beams which are able to slide, or supported by air suspension.

You seem to define the Jakobs bogie by the ability for each body to move independently. And yes I agree to that point. But then you say that this is not the case with the Duewag articulated tram. But it is, and it would be impossible for the tram to move from a straight track into a curve if each carbody could not move independently from the bogie. I know the SL79 Duewag car of Oslo by detail, and can describe it like this: In the central bogie there two separate slewing rings (a slewing ring is like giant ball bearing), one slightly smaller than the other, and both placed in the centre of the bogie. The top of one slewing ring supports one of the carbodies, the top of the other supports the other body. Thus they can move as if they had pivots on top of each other at the bogie centre.

According to the Wiki article the first successful use of the Jakobs’ patent was on the “Fliegende Hamburger” high speed train in 1932. I don’t know the criteria for “successful”, but the 1926 Harkort tram of Duisburg did use the Jakobs’ principle, also some suburban trains in Germany by 1927. But they were not the first, the same principle was used on a tramcar in Milwaukee in 1921, and I would not be surprised to see even older experiments.

Roy B.

There is a link to the patent in Wikipedia. If one reeds and understands the patent, it is obvious that the Duewag articulation is not an implementation of Jakobs patent. In the patent claim it is stated that independent movement is possible around the vertical axis as well as both the horisontal axes. As you describe the SL79 articulation independent movement is possible only around two axes, the vertical and one horisontal but not around the horisontal axis along the car. The two rectangles below picture the two carbodies seen from one end. A movement as in the figure is possible accordning to Jakobs patent, but is not possible with the SL79 (or M21) articulation.

The way I regard it, the main characteristic of the Jakobs' bogie is that one bogie supports two carbodies, and that alone is the invention. The original patent will surely contain a description of the rest of the bogie, how the carbodies are attached, as well as how the wheels are suspended.

Airplanes of today do not fit the description of the original 1903 Wright airplane, but they are still called airplanes because they have a motor and the ability to fly. The name Jakobs is associated with any bogie that supports two different carbodies, regardless of what the other technical solutions are. Sharing one bogie is the novelty, what makes it special, not the other features. Saying that all these people are wrong when they call a shared bogie a Jakobs' bogie, that is splitting hairs, as I see it. There is no way that you can point to a definition, because how the name is being used has become a fact by itself. Thus the Wikipedia article uses the Duewag articulation to illustrate the Jakobs' bogie, and this reflects the author's perception of how the name is commonly being used.

Regarding the Duewag construction (and I am describing the SL79, the one I know best): the carbodies are not rigidly fixed to the slewing rings and the bogie, in principle they would twist a little bit like your drawing shows. Rolling (twisting) is not desired, it would damage the articulation portal. Thus, there is a rod on top of the articulation, connecting and supporting the two carbodies, to prevent from the undesirable movement. There is no need for the two carbodies to be able to twist, because the bogies are flexible in the same direction, and the contact to the rails will remain. I guess railway carriages need to be more independently flexible to avoid the transfer of oscillations at high speed.

And reverting to what started this discussion - I have not studied the articulation on the 1926 Duisburg articulated tram, but I am almost certain to that this is even closer to the original Jakobs' patent.

Roy B.

[Harald]

If you had taken the trouble to read the patent, you had seen that cars supported by a common bogie existed before Jakobs invented the Jakobs bogie and that the invention he claims to have done, is a suspension that permits indpendent movement. You don't even have to read the entire patent. It's enough to read the first two sentences:

Der Gelenkwagen nach vorliegender Erfindung gehört zu der bekannten Gattung von Wagen, bei welcher der Wagen in mehrere Teile zerlegt ist, derart, daß die in der Mitte aneinanderstoßenden Enden auf einem gemeinschaftlichen Untergestell gestützt werden. Die Erfindung bezieht sich auf die Art der Stützung auf diesem Untergestell und hat wesentlich eine unabhängige bewegliche Lagerung jedes Wagenkastenendes mit Rücksicht auf das gegenüberliegende Ende zum Zweck.

I.e. the patent says that cars with carbodies supported by a common undercarriage are an already known type of cars and that the invention described in the patent concerns the type of the support and that the purpose is to make the car ends independently moveable.

So just as the invention of the airplane didn't turn hot air balloons into airplanes, the invention of the Jakobs bogie didn't turn other types of bogies supporting two car bodies into Jakobs bogies.

[ferrovialist]

If you had taken the trouble to read the patent, you had seen that cars supported by a common bogie existed before Jakobs invented the Jakobs bogie and that the invention he claims to have done, is a suspension that permits indpendent movement. You don't even have to read the entire patent. It's enough to read the first two sentences:

Der Gelenkwagen nach vorliegender Erfindung gehört zu der bekannten Gattung von Wagen, bei welcher der Wagen in mehrere Teile zerlegt ist, derart, daß die in der Mitte aneinanderstoßenden Enden auf einem gemeinschaftlichen Untergestell gestützt werden. Die Erfindung bezieht sich auf die Art der Stützung auf diesem Untergestell und hat wesentlich eine unabhängige bewegliche Lagerung jedes Wagenkastenendes mit Rücksicht auf das gegenüberliegende Ende zum Zweck.

I.e. the patent says that cars with carbodies supported by a common undercarriage are an already known type of cars and that the invention described in the patent concerns the type of the support and that the purpose is to make the car ends independently moveable.

So just as the invention of the airplane didn't turn hot air balloons into airplanes, the invention of the Jakobs bogie didn't turn other types of bogies supporting two car bodies into Jakobs bogies.

Sorry, I didn't read the patent description. If this is right, the story should be revised. If the shared bogie actually existed prior to Jakobs' patent, then you are right when you say that all other shared bogies really should not be called "Jakobs' bogies". Only those making use of the patent are rightfully "Jakobs' bogies". And that may be restricted to only a few, possibly those being made in the 1920'ies and 1930'ies. There is also the possibility that none were actually ever built. To be certain you would have to study the construction of each and one bogie type.

So where does this leave us? Mr. Jakobs himself seems to know that he was not the first to construct a shared bogie, he simply improved it. The shared bogie did not have a name. Then 25 years later, 50 years later and a 100 years later the name Jakobs (or wrongly spelt Jacobs) is being used for all kinds of shared bogies. Even the French use the term for the bogies used on the TGV train. And they certainly did not make use of the Jakobs' patent. In that respect they are all wrong. But then again, history is full of examples of inventions that had to be reinvented to become commonly known and popular. And history is also full examples of names and words being wrongfully used. Now if I ever see a bogie placed between two carbodies I would think of the name Jakobs, but if were to be certain I would have to study the drawings, or at least see the construction dismantled in some way. This would be an almost impossible task, this is what patent bureaus normally do, if the inventor is complaining. So even if I should know better, I may again be using the name Jakobs as most people understand the term.

Roy B.