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Old May 2nd, 2010, 01:02 PM   #61
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Quote:
Originally Posted by Hybrid 87 View Post
Sorry for the late post, but on 15th april the new tram was presented to public


Source - www.tvnet.lv
As I can see,this old track (on last photo) and not less than one track in the tram depot were modified to allow the exploitation of tramcars equipped with classical pantographs.But what about switches localized by the depot's entrance?
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Old May 3rd, 2010, 02:42 AM   #62
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Hybrid 87 did you go on this public demo ride? If so, how did you find ride quality, internal (and external) noise, quality of seats and such factors?

Is the track on which 15T travels in poor or reasonable condition (hard to tell from photos, the road surface looks terrible in places!)

Have you been on equivalent Bombardier/Alstom etc trams in other countries and if so, how does Skoda's ride compare?

(You have the first opportunity to give public feedback as nobody in Prague has been allowed to ride on it yet!)
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Old May 3rd, 2010, 03:43 PM   #63
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THIS IS THE LINE 6 WHERE SKODA 15T TRAMS WILL RUN AND WHERE THIS FIRST TRAM IS TESTED.

THE RAILS ARE NOT PERFECT BUT NORMAL

THE WHOLE CATENARY ON THE LINE INCLUDING INTERSECTIONS HAVE BEEN MODIFIED TO FIT PANTOS AND STANGS TOO.
http://www.youtube.com/watch?v=GyvTL...eature=related
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Old May 6th, 2010, 09:11 AM   #64
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Quote:
Originally Posted by Eurotram View Post
As I can see,this old track (on last photo) and not less than one track in the tram depot were modified to allow the exploitation of tramcars equipped with classical pantographs.But what about switches localized by the depot's entrance?
As Tramwayman said. The whole line was modified to allow the usage of pantographs and poles.


Quote:
Originally Posted by historyworks View Post
Hybrid 87 did you go on this public demo ride? If so, how did you find ride quality, internal (and external) noise, quality of seats and such factors?

Is the track on which 15T travels in poor or reasonable condition (hard to tell from photos, the road surface looks terrible in places!)

Have you been on equivalent Bombardier/Alstom etc trams in other countries and if so, how does Skoda's ride compare?

(You have the first opportunity to give public feedback as nobody in Prague has been allowed to ride on it yet!)
Sorry, I couldn't go on that ride. I had to work that day and somehow I don't think that asking a day of for taking a tram ride isn't the best excuse
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Old May 6th, 2010, 02:02 PM   #65
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Sorry, I couldn't go on that ride. I had to work that day and somehow I don't think that asking a day of for taking a tram ride isn't the best excuse
LOL, yes I understand. Oh well, we'll wait patiently for your impressions.
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Old May 6th, 2010, 02:37 PM   #66
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Duplicate post deleted.
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Old May 7th, 2010, 10:14 PM   #67
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Thank you Hybrid 87 for great presentation.

I don't think many people recognise the significance of this tram, world's first 100% low floor tram with pivoting bogies. It is really the next generation of low floor tram. Riga is lucky to have such an advanced vehicle!
Transport technology is a fascinating subject. I wish I knew more about it, and hope that finding this forum will help me to learn a lot.

There are an almost bewildering number of differing tram models operating in the world today. It would be interesting to have a thread on this forum where knowledgeable people such as yourself, could discuss the various merits and drawbacks of particular trams, and the features of their design and engineering which make them more or less suitable for particular conditions. [Perhaps there already is such a thread - I haven't yet had enough time to browse this whole forum thoroughly]

For instance, I read an article in "stadtverkehr" - edition of 5/10 - on the Solaris Tramino now operating in Poznan. My knowledge of German is imperfect - although improving - but, if I understood it properly, the article was saying that the Tramino, because of various design features of the motor suspension and wheels, was better than others at dealing with imperfections in the track - "Diese Tatsachen werden bei fast allen Herstellen von Niederflurtrams ignoriert..."

The article ends with the statement that "An Posens [Poznan's] Kreuzungen kann man alles an sich vorbeifahren lassen, Duewags ..., Schindlers ..., tschechisches RT6N-1, Combinos, alles schlaegt laut auf Kreuzungen, nur die 105N [Tramino] auffallend weniger!"

I am quite prepared to believe that Riga have indeed managed to acquire a very advanced vehicle in the Skoda 15T, but would like to see more explanation and discussion as to why it is so advanced as to represent the next generation of low floor trams.

It is noticeable that many pioneering low floor tram designs seem to have experienced severe problems, sometimes not apparent until the trams have been in service for some time (e.g. Combinos). This is understandable, as these designs are often trying out new ideas. It will be interesting to see whether or not Traminos and 15Ts manage to avoid this. [A great example of a daringly new transport design which was immediately successful without any major teething problems is the Boeing 747 Jumbo Jet]

This is my very first post to this forum, so please be indulgent about any infelicities in my post!

Best Wishes to all tram lovers and supporters of public transport.
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Old May 8th, 2010, 09:11 AM   #68
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To answer you briefly Frank H (without hijacking the Riga thread - I'm sure there is another general tram thread in this section, and the Czech Republic section of the forum contains very good discussion in English in its tram thread).

Skoda 15T has traditional pivoting bogies (as found on high floor trams) that do not have as bad impact on tracks and tram running gear (and quality of ride) as the fixed bogies of other modern 100% low floor trams. With four bogies per 30 metres 15T also has less "axle" (opposite wheels) load than other low floor trams with 3 bogies per 30 metres. For example Skoda 15T "axle" load 5.2 tonnes; Citadis 302, 6.9 tonnes; Bombardier Flexity GT6, 6.3 tonnes. Both of these factors are particularly more kind to trackwork in "legacy" systems like Riga. Even in new systems fixed bogies and higher axle loads will lead to long term higher maintenance issues.

About Solaris I don't know too much but I understand it is fixed bogie like Citadis and Flexity 100% low floor and so should have the same problems, but if it is in some way better I will defer to another forum member who might know more about Tramino.

If you use Google Translate it will help in understanding other languages (but not perfectly)!

Late edit:
Looking at Solaris website I see bogies are fixed like 100% low floor Citadis, Flexity etc so presumably it has the same problem. But they are making claims that I don't know would be possible. perhaps someone else can comment who knows more.

http://www.solarisbus.pl/en/tramino,ecology.html
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Last edited by historyworks; May 9th, 2010 at 03:38 AM. Reason: Additional information
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Old May 9th, 2010, 07:14 PM   #69
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MINIMUM HORIZONTAL CURVING RADIUS FOR

TRAMINO AND SKODA 15T ARE THE SAME I THINK.

18 METERS IS FOR TRAMINO
AND WHAT FOR SKODA?
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Old May 10th, 2010, 04:41 PM   #70
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Same for Skoda - but without battering tracks.
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Old May 10th, 2010, 06:11 PM   #71
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Quote:
Originally Posted by historyworks View Post
To answer you briefly Frank H (without hijacking the Riga thread - I'm sure there is another general tram thread in this section, and the Czech Republic section of the forum contains very good discussion in English in its tram thread).

Late edit:
Looking at Solaris website I see bogies are fixed like 100% low floor Citadis, Flexity etc so presumably it has the same problem. But they are making claims that I don't know would be possible. perhaps someone else can comment who knows more.

http://www.solarisbus.pl/en/tramino,ecology.html
Hi "historyworks".

Many thanks for your prompt and informative reply. It highlighted one of the particular challenges in low floor tram technology. I have come to an interest in trams after an interest in railway and "heavy" metro technology, which don't usually have this particular challenge.

In dealing with the problems of wheel-track interaction, there are questions both of the effect of the track on the wheels and also of the wheels on the track. It seems maybe that the Skoda 15T is especially designed to look after the track, whereas the Tramino is more concerned to look after the wheels - and to minimise noise. Of course the two aspects are inevitably linked, so I would expect both designs to be kinder both on the track and on the wheels than those designs (Citadis, Combino etc.) which have neither the special wheelset design features of the 15T nor those of the Tramino.

Another interesting aspect of all this is the degree of "sophistication" in a design feature - since a more advanced sort of design is not necessarily better for all circumstances.

A possible case concerns the Siemens ULF. The remarkable ultra-low floor height achieved in this design (180mm. as compared with e.g. 300mm in the Combino - other low-floor designs are often even higher, up to 370mm) has involved "...a new undercarriage. The axles had to be replaced by a complicated electronic steering of the traction motors."(Wikipedia). I seem to remember too that ULF has individually steerable wheels, i.e. it doesn't have bogies in the conventional sense of the term - indeed it doesn't even have axles. "complicated electronic steering" and individually steerable wheels enable both lower floor-height and a much gentler wheel-track interaction. The problem is that there is so much more that can go wrong. I would expect that ULF has had many teething problems. I don't know whether this is the case, but it might be significant that, as far as I know, only two systems - Vienna and Oradea (Romania) - have so far opted for this design. Or it might simply because it is more expensive, and that other systems might not be so concerned to achieve such a low floor level.

On re-reading the "Stadtverkehr" article I quoted previously, I realise that I had partly misunderstood it. Tramino is not the 105N, and has not yet gone into service in Poznan. The article was pointing out that the Tramino bogies and wheelsets are derived from those of an earlier Polish design - the 105N. The superior performance of the 105N in terms of noise at track crossings was then noted.

I note from the Solaris website that "Primary suspension is provided by conic rubbermetal elements, secondary suspension by two coil springs on each side of every bogie" and that "The bogies are connected - by means of shock absorbers and pushrods - to the body frames by welded intermediate members, suspension links, shock absorbers and rubber elements. This layout allows a selected displacement angle between bogie and car body and minimises the transfer of shocks to the body." This seems to be what the "Stadtverkehr" article was referring to, in claiming that the Tramino would be better at dealing with poor track conditions than most other designs.

I am sorry if this appears to be irrelevant to a Riga trams thread, but it has some relevance. The very same issue of "Stadtverkehr" also had a short article "Erste Niederflurstrassenbahn fuer Riga", with photos, about the arrival of 15Ts in Riga. Am I right in thinking that these are the first 15Ts into service anywhere in the world?

I have tried to find the English-language tram thread you referred to, but can only find a Czech-language one. I would be very grateful if "historyworks", or anyone, could provide the precise url of the English-language tram thread.

And if anyone can provide a link for a thread for general tram technology, I would be very grateful.
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Old May 11th, 2010, 08:27 AM   #72
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Thanks Frank H. Your reply is even more informative than what I have offered. The Skoda also has good ride so with pivoting bogies it has achieved both the objectives you describe. It is only natural for a modern rail vehicle to have bogies that rotate so the "first generation" 100% low floor design that has required short body sections on the trams in order to turn corners is never as satisfactory as rotating bogies. It also means more articulation breaks in the tram which robs from passenger (esp seating) space. In this context the Skoda is the greater generational advance.

However the Poles, like the Czechs, would have very good understanding of the issues with sub-standard track and curves in "legacy" systems and have obviously been more attentive to the issues. I think the products of Bombardier, Alstom etc are pitched for the new western "light rail" market where the track is new and in good condition and is designed with easy (large radius) curves. But large radius curves are not possible on many street systems and of course even those new systems will have deterioration over time. I think this was the problem with Variotrams in Helsinki:

http://en.wikipedia.org/wiki/Variotram#Helsinki

You will be interested in this:

http://www.railway2007.fd.cvut.cz/pr...apek+Kolar.pdf

The ULF is for systems without platforms, it would be too low for modern light rail platforms. And yes commentary from Austria indicates teething issues and maintenance costs. Also has many articulations.

Re 15T, according to Czech thread they will be in service in Prague first (June). Riga is September?

Czech tram thread is mostly in English, worth having a read through from page 1 (also previous CE tram thread):

http://www.skyscrapercity.com/showthread.php?t=621329
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Old May 11th, 2010, 11:19 AM   #73
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AS I KNOW THAT VARIOTRAM HELSINKI CAN TURN ON 15,5 M RADIUS.
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Old May 11th, 2010, 11:51 AM   #74
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AS I KNOW THAT VARIOTRAM HELSINKI CAN TURN ON 15,5 M RADIUS.
Maybe they can all turn on 15 m radius (including Skoda) but with fixed bogies this is a big problem. Usually only done in depot turnouts etc and very carefully. In Helsinki Variotrams started cracking under the strain iirc.
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Old May 11th, 2010, 07:44 PM   #75
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Originally Posted by historyworks View Post
However the Poles, like the Czechs, would have very good understanding of the issues with sub-standard track and curves in "legacy" systems and have obviously been more attentive to the issues.

http://www.railway2007.fd.cvut.cz/pr...apek+Kolar.pdf
I don't think so, tram tracks in Poland are in almost all cases upgraded for radius of 25, or at least 20 meters. Now it's really hard to find tighter curve, yet they still occur. I think that trams can handle smaller radii than producers declare, but they deny it because it causes much more tear and wear.

BTW, thanks for the interesting article!
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Old May 11th, 2010, 09:06 PM   #76
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Hi "historyworks".

Thanks for another very helpful reply.

Quote:
Originally Posted by historyworks View Post
Thanks - very interesting.

I note that this paper predates the articulated bogie design of the 15T.

If the 15T proves to be a successful design, and there already seem to be indications that it will be, then Skoda are to be congratulated on a relatively simple and elegant solution to the low-floor tram bogie challenge. While it hasn't got the "sophistication" of, e.g., the ULF design, it will almost certainly be a more reliable performer in most tramway situations. And much cheaper too.

Someone in Skoda is to be congratulated for "lateral thinking", a mark of genius. If there were Nobel prizes for transport engineering, then I suggest he/she would be a good contender.

Through your advocacy, 15T has become one of my favourite modern trams. A great pity that it is unlikely that we will ever see it over here in the UK. There is a tramline at the bottom of my garden - but all we get are Bombardier Flexitys. They are OK performers, but not, in my opinion, an attractive design visually, although better than most Citadis.

Quote:
Originally Posted by historyworks View Post
Re 15T, according to Czech thread they will be in service in Prague first (June). Riga is September?

Czech tram thread is mostly in English, worth having a read through from page 1 (also previous CE tram thread):

http://www.skyscrapercity.com/showthread.php?t=621329
Thanks for the link - I'll follow it from now on, although it seems that nowadays the majority of posts are in Czech.

I gather that the Riga 15Ts are air-conditioned. Are the Praha ones also?
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Old May 11th, 2010, 09:41 PM   #77
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I realise that "articulated bogie" is a misleading way to describe the bogies of the 15T. They are pivoting bogies, two of which per tram are situated under the articulations.
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Old May 12th, 2010, 02:10 AM   #78
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Quote:
Originally Posted by Tramwayman View Post
AS I KNOW THAT VARIOTRAM HELSINKI CAN TURN ON 15,5 M RADIUS.
Actually on Staedler website specification for Variotram is minimum curve 25 m radius but, as I said, in depots etc they may have to negotiate tighter curves but very slowly. This is a problem in Australia with Melbourne system (down to 16 m radius) and Sydney (20 m radius) the Citadis/Combino/Variotram trams have to slow down to walking pace on these curves (about 4 kph) which does not do wonders for maintaining a high average speed and wastes time on traffic light sequences while the big caterpillars crawl round the corner! Ridiculous really.

Thanks for information about Poland WotaN.

Frank H it will be hard for Skoda to break into "western" markets because of existing turf prejudices favouring "western" manufacturers (even though Czech Republic IS in the west LOL!). However they are getting well-established in US market. I vote for Skoda too but what can we do?

Back on thread I now read 15T public service in Riga scheduled for June (?) so it may be neck and neck between Prague and Riga who goes first.

(PS: Prague 15T is air conditioned in driver's cab only. In Riga I gather aircon is not for summer "heat" but for minus 40 temps in winter! We have the opposite problem in Australia! It seems DPP thinks Czechs don't need aircon but I spent last hot summer in Prague and I think then it might have been a nice thing to have in the trams!)
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Old May 12th, 2010, 10:17 AM   #79
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Well I have read that specially Helsinki Variotrams are avalilable to turn on 15,5 m radius.

Also Variotram for Munich can turn on 14,5 m/

Bombardier Cobra can also turn on 14,5 m/



Also The acceleration of this new low floor trams is not what needs to be for me.
1,1 or 1,2 that's pretty stupid.

When Pragoimex Varios ca do upto 1,8 maximum acceleration as it's old friend Tatras.
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Old May 12th, 2010, 11:51 AM   #80
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Quote:
Originally Posted by Tramwayman View Post
Well I have read that specially Helsinki Variotrams are avalilable to turn on 15,5 m radius.

Also Variotram for Munich can turn on 14,5 m/

Bombardier Cobra can also turn on 14,5 m/



Also The acceleration of this new low floor trams is not what needs to be for me.
1,1 or 1,2 that's pretty stupid.

When Pragoimex Varios ca do upto 1,8 maximum acceleration as it's old friend Tatras.
Turning radius I don't know how they can do this without putting bogie on a pivot - otherwise the bogie is normally fixed to the tram frame at 4 points.

Greater acceleration is always possible, but it is constrained to comfort of passengers.
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