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Old October 30th, 2007, 08:39 PM   #481
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Quote:
Originally Posted by Songoten2554 View Post
pretty cool concept it could work in cities that can't afford Metros like Miami we need that sort of system there

is overhead wires bad or good?
Depends on the city itself: I personally like overhead wires because it shows that the transit infrastructure itself is being "green". It's even better if the electricity used on the overhead wires is from a green source (i.e. Wind power, hydro, etc.).

Vancouver, BC has the second largest trolley network in North America and all of the electricity is from Hydro.

Overhead wires do have a downside of course: "derailing", where the bus/StreetCar disconnects from the overhead wires due to speed, etc. This almost never occurs with LRT of courese. And it can look very messy... Especially when overhead wires meet at an intersection.

But remember, in todays society, many transit networks have electric-battery powered buses, hybrid buses, hydrogen buses (well the largest fleet will be in Whistler, BC), etc. And some (for sure not hydrogen) are much cheaper since you dont' need to install new infrastructure AND the fact that many of the buses themselves are cheaper than the electric ones. The ones in Vancouver I think costed a lot... I don't have the exact number for that though...
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Old November 6th, 2007, 04:16 AM   #482
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could a concept like that be applied to buses?
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Old November 6th, 2007, 02:14 PM   #483
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There are buses(trolleys,actually) that dont need overhead wires constantly.
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Old November 10th, 2007, 12:22 PM   #484
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Quote:
Originally Posted by zaphod View Post
could a concept like that be applied to buses?
Only if buses can do regenerative braking.
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Old November 10th, 2007, 01:54 PM   #485
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Only if buses can do regenerative braking.
Actually Hybrid-buses that are in service do.
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Old November 10th, 2007, 02:24 PM   #486
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Both concepts are really cool. Maybe a combination of battery, flywheel, and solar panels on the roof of trains and stations could result in a fully competitive LRT technology.
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Old November 10th, 2007, 03:22 PM   #487
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Quote:
Originally Posted by RawLee View Post
There are buses(trolleys,actually) that dont need overhead wires constantly.
In Seattle there were Dual Mode trolleybuses, they ran under the wires in the Downtown Bus Tunnel (basically a subway, but with buses), then they swiched to diesel mode to go to the suburbs. These were Breda buses, in service from 1990-2004. 59 of the Breda buses were converted for use on the Seattle Trolleybus Network, which was never connected to the Bus Tunnel. Now the Tunnel uses articulated buses, Diesel-Electric. They can go into a tunnel mode, and are almost completely electric only. The Tunnel was closed for 2 years to make room for Light Rail, and Buses and LRT will serve the tunnel at the same time.
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Old November 10th, 2007, 07:16 PM   #488
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An LRT with a third rail? Isn't that quite dangerous to pedestrians who share the street?
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Old November 10th, 2007, 09:28 PM   #489
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The LRT uses overhead wires. The trolleybus wires would probably be incompatable by terms of voltage. The buses were due for replacment, and Metro probably thought that it would be too expensive to keep running trolleybuses in the Tunnel.
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Old November 11th, 2007, 12:52 PM   #490
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I'm suspecting that babelfish may be causing some confusion to some of the people here, so I am provided a translation of the original post (as I speak Japanese).

@japanese001:
失礼致しますが、自動翻訳処理の正確が不足訳、日本語ができないフォーラム人が詳しい理解を頂けますように、私が自分で翻訳したいと思っております。ご了承宜しく御願い致しますね。

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Originally Posted by japanese001 View Post
車内に搭載した電池だけで走り、停留所に止まった数十秒間に消費分を急速充電できる路面電車を、財団法人鉄道総合技術研究所(東京都国分寺市)が開発した。

The Railway Technical Research Institute (in Tokyo's metro suburb of Kokubunji City) has developed a LRV that runs on a battery located on board the LRV itself and can quickly recharges the battery during the 10s of seconds of braking for a service stop.

11月末から、札幌市で性能を確認する実証試験を始める。

In Sapporo City (the main city on the northern island-province of Hokkaido) around the end of November, trial testing began to confirm the efficiency of the technology.

床が低いバリアフリー型の車両で、搭載したリチウム電池をフル充電すれば約15キロ・メートル走れる。減速時には、電車の勢いの7割を電気に戻して電池に蓄える。停留所では、パンタグラフを上げて架線から補い、急速充電する。現在の路面電車に比べて約1割の電力量を節約できるという。来年3月まで行われる実証試験には、ニッケル水素電池で動く川崎重工の車両も参加。よい結果が出れば、省エネ路面電車の実用化が近づく。

In a low-floor accessible vehicle design, the on-board lithium battery can last for a service run of about 15km (non-stop) on a full charge. When braking, the vehicle can restore 70% of the energy back into the battery. The difference is compensated for by an overhead wire at station stops and quickly charged to full via a pantograph raised by the LRV. They say that compared to current LRVs, this vehicle saves about 10% energy consumption. Trial runs being carried out through to next March will also include the participation of a Kawasaki Heavy Industries model working off a nickel-hydrogen cell. If the results are good, the real-world application of an energy-saving LRV will be one step closer.

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Old November 11th, 2007, 09:55 PM   #491
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thanks TRZ for the translation really i can't read kanji as the japanese language for me is very complicated and very hard to understand thank you

i believe this is a good idea because the trains can run in case there is no overhead wires even though overhead wires are run by hydro power and other means of green energy
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Old November 12th, 2007, 02:10 PM   #492
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Quote:
Originally Posted by Songoten2554 View Post
thanks TRZ for the translation really i can't read kanji as the japanese language for me is very complicated and very hard to understand thank you
Japanese writing is complicated indeed (grammar is actually simpler than people think). Lots of people can't speak/read Japanese though, no need to make excuses. You ever studied Japanese though? I thought you hadn't but you make it sound like you have.

Anyway, the original poster did provide a translation except it was translated by a computer. The way Japanese is typically written often involves plenty of implied components that a computer simply can never pick up. My translation is using more words and content than are in the original document because in order for the English translation to be coherent, I have to add in the implied details that are not necessary in the Japanese original. These are subtle things, but they make a world of difference in translation cases.

Quote:
Originally Posted by Songoten2554 View Post
i believe this is a good idea because the trains can run in case there is no overhead wires even though overhead wires are run by hydro power and other means of green energy
Overhead wires are not necessarily hydro power, that's only one possibility. They can come from Coal, Oil, Gas, Nuclear, or other toxic forms of power generation, or alternatively they could also be getting their power from solar, wind, geothermal, or tidal power.
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Old March 19th, 2014, 03:23 AM   #493
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MISC | All about Trams/Streetcars/Light Rail Vechicles

This thread is dedicated to technical, economical, historical issues and anything else related to this type of transport.



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Old March 19th, 2014, 08:09 AM   #494
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Fantastic idea for a thread, I look forward to it!
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Old March 19th, 2014, 04:35 PM   #495
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Are the trams from today's generation more energy efficent then the old ones? How and why?


Quote:
Originally Posted by Sunfuns View Post
Probably also less energy efficient than the current generation of rolling stock.
Quote:
Originally Posted by Slartibartfas View Post
Would be interesting to check. Why do you think so? Electric engines have little room for further efficiency improvements because they have been extremely efficient for a long time.

Judging by the power of the electric engines energy consumption of old and new models seem to be fairly similar. Per passenger the old units even seem to have slightly less engine power. Of course that is not a proof for actual consumption but its a hint.

And of course, if we are calculating energy costs you have to consider the life cycle as well. If you discard units already after 20 years you need a whole lot more energy for new units than if you discard them after 40 years (even if you include maintenance effort)
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That's a bit more complicated.
It's true, that electric engine as per se is very efficient, and doesn't have much room for improvement. But what is really progressed for last 40 years - it's control systems.
40 years ago there was no real alternative rheostat-based control. I'm no specialist, so I can give only very basic insight of topic... The basic idea of rheostat-based control - there is a 3 power levels that achieves full efficiency (no extra waste heat and wasted electricity) - "serial connection (of engines)", "serial-parallel connection", "parallel connection". But only 3 levels of power is not enough for smooth ride, tram would accelerate and brake to rapidly, dropping standing passengers to the floor, going either too fast or to slow... So intermediate power levels are created between the main 3, with the help of resistors, that turn some of supplied electricity into waste heat. Right after the start, there are lot of connected resistors, but as tram accelerates, they are disconnected from circuit, until none left, then system reconnects engines in different pattern and connects resistors back, starting the resistor cycle again (e.g "serial connection, all resistors connected" -> "serial connection, lots and lots of resistors" -> "serial connection, lots of resistors" -> "serial connection, some resistors" -> "serial connection, few resistors" -> "serial connection, no resistors" - "serial-parallel connection, lots of resistors" -> ... -> "serial-parallel connection, no resistors" -> "parallel connection, lots of resistors" -> ... -> "parallel connection, no resistors").
It's totally OK for freight and intercity railways, where train may go at constant speed/traction for hours - driver set system to power level wit no resistors connected, so all the electricity goes into traction, not into heat. But this isn't the case for tram - it operates in start-stop mode due to frequent stops, intersections, street lights, traffic and thus spends lot of time with resistors connected into circuit, wasting electricity into heat.

The modern trams use semi-conductor-based control system, which can be set to any power level (not just basic 3) without using any resistors, which results in very smooth acceleration (in rheostatic systems there are typically about 20-40 levels of power, while in semi-conductor based, power can be adjusted by really small portions) and no extra waste heat produced, no electricity wasted. Such systems have very slightly lower base efficiency (e.g. at maximal power) due to loses in different semi-conductor stuff, but in case with trams and their constant starting/stopping, lack of need for resistors during acceleration results in electricity savings.

P.S.: If any of professionals have remarks and corrections - they are kindly welcomed, my education have nothing to do with transit and electricity, anyway.
Quote:
Originally Posted by Sunfuns View Post
I'm no professional either, but another area where efficiency might be gained is using lighter construction materials and thus decreasing the mass which needs to be moved around. That's the main way how airplane become more energy efficient...

But it would indeed be interesting to see numbers and compare 40 year old tram (in good condition) and a brand new one.
Quote:
Originally Posted by XAN_ View Post
I doubt that. Classic Tatra T3, one of the most numerous trams of the world of 60s-70s-80s weighted 11,5 t per 10 m of length, while 90s-00s Siemens ULF (Vienna modern tram) 12,1-12,3 t per 10 m respectively.
I suppose it just not easy to make trams lighter without making it to fragile... And unlike plains, where mass is lifted and must be provided with enough energy to counterforce gravity pull of Earth, here it rolls using steel wheels on steel, which is really undemanding in energy terms, it consumes even less energy than rolling rubber on asphalt.

Well, in Kyiv authorities claimed that replacing 70-80-s tram electrics with modern electronics can save up to 40% in better case scenario.
Quote:
Originally Posted by Slartibartfas View Post
Interesting comments. It would be interesting to see how they compare in terms of energy efficiency indeed (in a realistic tram setting). It would be even more interesting to see some lify cycle foot print calculation. You'd also have to include the fact that ULF trams apparently need a lot more maintenance than the old units as well as causing more stress to the tracks. I think it is a very good decision that the Wiener Linien are going to switch to another model.

And would be modernization of the motor control be an option? Are old motors compatible with semi-conductor based control?
Quote:
Originally Posted by XAN_ View Post
Yes, it would be really interesting to see the real stats, but at least in Ukraine, trams, unlike railway trains, aren't equipped with electricity meters

Considering lifetime footprint - it should be considered, that low floor trams have lower dwelling times at stops, so in the same schedule it's possible to drive them less "aggressively" (e.g. with less acceleration and braking), thus consuming less energy, compared to classic tram.
And if that aren't to confusing, low-floor trams have higher chances of attracting passenger from auto... All those indirect stuff a so confusing.

There are semi-conductor solutions both for classic DC motors and now popular (for number of reasons) AC. But, I suppose, whenever trams are refurbished, engines are to be changed, or at least, refurbished too.
Quote:
Originally Posted by Slartibartfas View Post
Mass is very significant. If it were only to roll on lage distances it would not be that important but trams have to accelerate very frequently an then it is all about mass.
Quote:
Originally Posted by NiGhtPiSH View Post
Yes and no. The main variable of the "weight" factor is axle load.


In my opinion E2 are superior than the ULF, and have been since 2006 overhauled with regenerative brakes. Their simple construction allows for easier maintenance and in winter they are much more comfortable.
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Old March 19th, 2014, 10:00 PM   #496
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What minimum pax/h/direction is needed for a Tram/Streetcar line to be viable? I different project I've seen different numbers from 1200 to 5000. AFAIK for more then 10000 a heavy rail soulution is needed (Metro). But which is the limit where bus transport is not enough enymore, and a light rail solution is needed. And in this regard which is the difference between normal bus service, BRT, Tram/Stretcar or LRT ?
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Old March 25th, 2014, 08:03 PM   #497
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United Streetcar is the first manufacturer of modern streetcars in the United States.






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Old March 26th, 2014, 05:29 AM   #498
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I think USA has serious problem with deisgn, almost all the public transport vehicles are ugly. They really do not care, it just must be wide box with seats
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Old March 26th, 2014, 12:53 PM   #499
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Some are ugly, and some are really ugly, San Jose for instance:

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Old March 26th, 2014, 04:50 PM   #500
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Yeah it is, a lot of ugly trams or another mass transit vehicles, but are some beautiful ones just very rare.


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Some are ugly, and some are really ugly, San Jose for instance:

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