APS tram lines

[velotrain]

I found this image of a Bordeaux tram a few months ago, and I was so overwhelmed by the beauty of the seven-section articulated tram that I only just noticed what is missing from the picture.

 

 

 

 

I saw the folded pantograph above the three men talking, and then noticed what looked like a third rail of some sort in the middle of the track. 

I briefly wondered if somehow Lionel / Marklin track had become 1:1 scale reality.

 

I then discovered the background.

 

http://en.wikipedia.org/wiki/Ground-level_power_supply

 

No doubt some of you are familiar with this technology, but it is new to me.

[kvp]

Not as effective as it seems and a larger rain or any kind of snow or ice can stop the whole system by causing a ground fault. This is why ground level power was abandoned in Budapest over a hundred years ago. A better solution, already in use for trolley buses and will be used on some tram lines too is to use storage batteries to bridge ovearhead-less sections. This means a trolley or a tram can run a few miles without any external power source. All special systems (the battery charger and the batteries) are on board the vehicles, so the track doesn't have to be intelligent. The french like to experiment with various old and less effective technologies, but usually the new versions cost more and are less effective than the basic two tracks and one overhead technology.

[velotrain]

The Wiki article mentions the problems - and an ultimatum the mayor of Bordeaux gave.

 

When I first noticed the absence of poles / wires, my first thought was batteries.  

 

This probably won't be an issue in the U.S. - or Japan, as I'm not sure if we have any urban districts that are considered historic enough, and the Japanese seem to just love stringing overhead wires of all sorts everywhere.

[Jace]

So called on-board energy systems (batteries and capacitors) are already pretty well established on trams. As an example, Kawasaki has/had been marketing their SWIMO tram (http://www.kawasakirailcar.com/LR_SWIMO) which is not much more than a platform for their Gigacell batteries. Their thought is that the cars can be charged while in a station, run without wires between stops and then recharge at the next one. Bombardier and more recently CSR in China have something similar under development but using capacitors (http://www.railjournal.com/index.php/light-rail/csr-unveils-100-supercapacitor-powered-tram.html). No sales that I know of on these yet.

 

More conventionally, tram builders can easily buy add-on battery systems from suppliers like Saft (http://www.saftbatteries.com/press/press-releases/saft%E2%80%99s-industrialized-onboard-li-ion-battery-system-regenerative-traction). These types of systems are being installed on trams in the US in Seattle, Detroit and Dallas. The car prices do go up a bit when these systems are installed.

 

The battery systems are a bit simpler than the Alstom APS in that all you need to do is add a battery pack to the cars. One issue however is the added weight. First the car structure and trucks need to be able to handle the extra weight, then you need to move and stop the car with that added equipment. The longer you run under battery power, the more weight added. I know of one case where significant car structure redesign was needed because the off wire runs were relatively long. Here the stock trucks were also no good due to the increased axle loads.

 

Economically the trade off is higher car capital and maintenance costs versus the cost to install and maintain the overhead wire. On hybrid buses in New York, both capital and maintenance cost increases were very high compared to standard diesel buses. It didn't help that their batteries were only lasting 1 year, not the expected 3. Even after they got the life on them extended, battery replacement costs are still high. Economically it probably doesn't make sense for them to keep buying hybrid buses, but there's no going back politically...

 

[velotrain]

Thanks for all the info Jace.

 

I was curious about CSR, and followed it to this:

 

http://www.railwaygazette.com/news/urban/single-view/view/guangzhou-tram-line-opens.html

 

It sounds impressive, "CSR says the vehicles will draw sufficient power during a 30-second stop to operate independently for up to 4km."

 

 

This could make tram modeling even easier - along with imaginary wires, we can now have imaginary poles ;-)

[kvp]

4 km at 40 km/h is 0.1h or 6 minutes (x12). A common phone battery works for around 24 hours after 2 hours of charging (x12). This seems plausible.

 

Diesel hybrids are financially

good if they charge the battery only during braking and use it only during acceleration. The rest can be straight diesel electric operation. Natural gas electrics are even better. Start stop systems and mechanically coupled ones

 

are problematic though. A plug in hybrid (or a trolley hibrid) can be very cost effective.

[westfalen]

The Dubai trams use the APS system.  From the overhead view you can see they have pantographs for moving around the depot which is equipped with overhead wires.

 

The system had only been in public operation for a week when I was there last December.

Edited April 9, 2015 by westfalen

[stevenh]

That is a great looking tram!

[velotrain]

The Dubai trams use the APS system. 

 

They likely don't have the issues with excessive rain that plague Bordeaux ;-)

[Guest ___]

Years ago when DC still ran PCC streetcars, there was an ordnance that prohibited overhead lines downtown and around Cap-Hill. Once the trolley would hit the boarder to the no-overhead zone, they would switch to picking up power from an underground channel between the rails. http://en.wikipedia.org/wiki/Streetcars_in_Washington,_D.C.

 

The rules prohibiting overhead streetcar wires have long been rescinded since as the DC Streetcar days. Currently, the DC Streetcar system has overhead wires all the way through to Union Station. Of course as to how long those wires are there is assuming it ever begins revenue service as there is word, that DDoT may scrap the entire system before ever a paying passenger steps aboard.

[velotrain]

Shashinka - I tried the link and got "Wikipedia does not have an article with this exact name."

[stevenh]

http://en.wikipedia.org/wiki/Streetcars_in_Washington,_D.C.

 

The dot at the end was missing. (seems the forum code thinks you're trying to finish a sentence rather than include punctuation in the URL)

Edited April 10, 2015 by stevenh