Charlotte Heritage Trolley System and Trolley Barn/Museum

[monsoon]

Agreed. I was quite dismayed when Ramona of Matt & Ramona fame (if you can call it that) got on channel 18 and called the Trolley a waste of money. Her reasoning was that she could walk faster, though from looking at her I would say she really hasn't done much of that. Matt at least said it was a good attraction for kids.

No wonder I am much happier listening to Satellite radio.

[orulz]

What's going to happen to the trolley stops and shelters in south end during light rail construction and after the light rail is done? Will some of them stay in place? For the most part, the trolley stops are offset from the LRT stops. For example, there's a trolley stop at Park, East/West, Tremont, and Atherton Mill, but the LRT stops at Rensselaer, East/West, and New Bern. The only stop they have in common is East/West.

I guess it just seems like a shame to demolish the trolley stops.

[dubone]

The trolley stops will not be demolished. The trolley was built in anticipation of an eventual LRT line. The trolley stops are at different locations than the LRT stops.

Trolley:

- Atherton Mill

- Tremont

- East/West

- Park Ave

- Bland

- Morehead

- Stonewall

- 2nd

- 6th

- 9th

The LRT

- East/West

- Rensselaer

- Carson

- Stonewall

- 3rd

- Trade

- 7th

The only stops that coincide intersections are Stonewall and East/West, but the Trolley stop is in a slightly different place than the LRT station will be.

It is unclear whether they will reuse the caternary poles from the trolley or not. But it is possible that they will have to rebuild the wires, etc., for when they double track the whole distance.

As far as the Ramona comment, that is pretty funny. I think I heard that they apologized, saying the project itself wasn't a waste of money, but as a transit option, it was just a bit slow. To be honest, I agree, with that criticism. It really does take a lot to wait for the trolley, and while it is uptown, it is only a little bit faster than walking, considering the stops at every intersection. However, overall, it was not a waste of money, as it is extremely popular as a tourist destination, and many people make a day out of it. Either way, the "slow" criticism will no longer be valid after the LRT is running, as the intersections will get gates or lights, and the trolley will no longer run as slowly as it does now.

[RiverwoodCLT]

Once the LRT is in place, there will be signal lights, so the trolley will not have to stop at intersections. Iwas told that it would cost too much to put up signal lights and then taken them down and reconfigure for LRT.

[DigitalSky]

aw i'm gonna miss the trolley shutting down for a year!

[orulz]

The Charlotte Trolley does not use catenary wire. I did not understand the terminology until someone explained it to me, but there is a significant difference between simple direct-suspension overhead wire and catenary wire. Catenary wire has the two-wire design with the current-carrying wire suspended beneath a support wire, as seen in the picture.

Trolley poles (seen on the charlotte trolley) are generally used where there is direct-suspension wire. Catenary wire is generally used for higher speeds (conventional electric railroads, old interurbans, and modern LRVs). LRVs have pantographs rather than trolley poles, which I believe work better with catenary wire.

That makes me think that the south LRT will probably use catenary wire, though I'm not sure

[monsoon]

Actually catenary is a generic engineering term that descibes the bend in cables when suspended in air. You have catenary cables in bridge construction and as we all know here in electrified rail systems when a 3rd rail isn't used.

As a result a catenary cable is simply a suspended cable and it this case it is electrified. The suspended cable that we see for the Charlotte trolley and the one that will be suspended for the LRT (similar as shown in your photo) can both be referred to as a catenary cable and often are on this subject. The differences in suspension are to accomidate the differences of the vehicles in question. PTO is commonly by the much older trolley poles as in our antique trolley, or by pantograph which is the modern equivalent.

In any case, the LRT will use a different set of catenary cables than that of the Trolley. The are not compatible systems.

[orulz]

You are right about Catenary being a generic term describing the arc of a suspended wire, and it is certainly correct to use it for both one and two-wire overhead lines.

I sort of figured that, in the case of a single-wire system like the Charlotte Trolley, the catenary arc is an undesirable phenomenon and the wire is tensioned to lessen the effect, so it would not be called "catenary" becayse that describes an undesirable property of the wire.

In the case of a two wire system, the catenary arc is used as in a suspension bridge, to support the conducting wire at more points without adding any poles, so the term "catenary" could be used in a positive light.

I think I may have over-analyzed the situation, though.

[dubone]

. So at the very least, the wires themselves, and the electric infrastructure must be rebuilt for the LRT, over what is there now. But does anyone know if the poles themselves will have to be changed as part of those changes?

Some renderings of the uptown system, have entirely new poles. Actually, they have brick pillars as the base of the poles, but I doubt that pass budget cuts.

So in general, the theme is that some of the stuff built for the trolley will remain, some will be revised for LRT, and the rest replaced. The stations and station furniture is definitely staying, some of the tracks will remain, some of the tracks will be reconfigured, the wires and electric infrastructure replaced, and possibly the poles. Sidewalks, crossing lights, LRT stations, and the second track will be added new for LRT.

[monsoon]

Well I am not so sure now.

I have not seen any plans, but I don't see why the trolley poles are not going to remain. Surely they would not have spent the money for decorative historic looking poles to only have to tear them down a year or so later. (I could be wrong though) It is an interesting engineering challenge however. Note this early rendering of the Charlotte LRT. There are no trolley poles shown.

However if you notice in this photo, a LRT pantograph may or may not work in this arrangement. It is specific to the trolley pole installed on top of the vehicle.

But on this photo, you can see that the cable is split and appears to be a double cable for the length of the track heading south which might mean it was meant for double tracking, but then again it doesn't look stiff enough for a modern pantograph. (anyone know more about this)

And finally how do you fit another track here without tearing down the station or the trolley poles? (when they build the university section as the LRT will not initially go up this far) Since the trolley is designed specifically for these platforms, it is going to have to travel on the rail next to the platform for safety reasons. This would make me think that CATS is going to run two new tracks around the Trolley stations and the station could be bypassed entirely. It's hard to say without seeing specific engineering diagrams.

I know that in France they configured the Avanto to run on dual voltage. i.e. 750 volts which is what the Trolley uses, and higher voltage for more modern parts of the line. Maybe this is one of the reasons there LRT is only going to travel 15mph in the downtown section. Lower voltage.

[dubone]

The last photo is of 9th Street. The south LRT line will end at 7th Street, so there will be no changes on that stretch visible in the photo.

When/if LRT is extended to NoDa in 5-10 years, they will need to decide what do with that stretch. There are currently plans for a 9th Street LRT station for the NE line, but I think they plan to build it between 9th and 10th. There will definitely be a lot of trolley construction torn up, though, when they add a second track north of 7th.

[monsoon]

The last photo is of 9th Street. The south LRT line will end at 7th Street, so there will be no changes on that stretch visible in the photo.

I think I mentioned that.

[dubone]

Oh gosh, sorry about that. My page jumped when it loaded the photo, and I guess I didn't go back to read the rest of the paragraph.

I don't think even CATS knows exactly what they plan to tear down for the NE line, as they aren't that far in the engineering. But definitely they will not use the existing trolley station for LRT. They will either replace it with an LRT station, build an LRT station on the other side of 9th and leave this one for just trolleys, or build some kind of a blended station that works for both.

[orulz]

I think - could be wrong, though - that the overhead wires in Charlotte are 750 volts, and they will remain at 750 volts DC when modifications are made for the LRT as well. At the very least, the Gomaco trolleys and the #85 are all capable of running under 750 volt wire as well.

I have no idea what it'll look like when it's done, though. I think it would look best with a single set of poles between the tracks supporting both wires. They could probably just put new supports on the old poles in that case. It would be no problem to move the poles further out to accommodate the trains, if a center-pole setup is not possible.

The question is, are the old poles tall enough to accommodate a double-wire catenary suspension setup? Assuming that's what Charlotte will be doing here.

Great photos, by the way, Metro!

[monsoon]

Thanks!

The Trolley does operate at 750 volts. I'm not sure if it is DC or AC. Modern light rail is typically operated around 25,000 volts AC in comparison as it is much more efficient (electrically).

I believe the Avanto can configured to operate on both voltages but it's not clear of CATs intends to do so.

[orulz]

Modern, electrified conventional railways generally run at somewhere between 12,000 and 25,000 volts AC, at between 16 and 60hz. The particular specification depends on what country you are in and in some cases what line you are talking about within that country. On some lines where legacy electrical systems are still in place, conventional railroads still use DC.

High-voltage lines are generally used only on conventional railroads, presumably because the vehicles are heavier and the rights of way are better segregated. A 25,000 volt overhead line is much more dangerous than 750 volts, so on an LRT line where grade crossings and street running are common, higher voltages are generally not used. I am not sure why high-voltage systems are always AC and low-voltage systems are always DC.

In the US, 750 volts DC seems to be the rule for new light rail systems. I checked it out for Los Angeles, Portland, Minneapolis, Denver, and the Hudson-Bergen line in New Jersey.

Older systems in the US seem to run at 600 volts DC. I checked this with New Orleans, the Newark city subway, San Francisco's Muni, and Boston's Green Line.

In Europe, there are places where light rail vehicles run in mixed traffic on conventional railroads, and in that case the vehicles need to work with the existing electric lines, which in some cases might be high-voltage AC.

All in all, railroad electrification worldwide is a very confusing subject!

[dubone]

DC is nice because it doesn't kill you. Death is not a good connotation when trying to build a friendly urban streetscape . That is the extent to my knowledge of what you guys are talking about.

[monsoon]

In the modern USA power distribution system, line voltage is always divisable by 120 and is always 60Hz.

It's common to see 69,000 & 34,500 Volts on power lines that travel by ordinary streets. Even the power systems that travel through neighborhoods, including underground ones going down the streets range from 2400 volts to 34,500 volts before it passes through a transformer and dropped to 240 volts and sent to your house. (many commercial customers take 480 volts)

The mathematics behind AC power transmission involves complex math and imaginary numbers, but the higher the voltage the less loss there on the power lines. A 25,000V (its probably 27,600v) is going to be much more efficient than 750V for the same amount of energy used. This is why some long distance transmission lines exceed 500,000V.

25,000V is no more dangerous than 750V as both will easily kill anyone who comes into contact with one of these lines. The lower voltages are found on much older transit systems is because you are talking about 1930s technology where high voltage transmission was not understood that well or beyond the technology of the day. Another reason that you see odd voltages on older systems is that many transit systems used to generate their own power and they did not use standard line voltages used in the North American power distribution system. These days however that would be impractical and we can expect Duke to supply power to the LRVs.

[dubone]

Does 750V DC kill someone? I always thought it was the case that DC didn't hurt anyone, but AC did, and that is why Edison originally pushed for a DC-based electrical system. I read that he once did a presentation to prove the dangers of AC by killing an elephant with it.

I might be mixing some of that up, as I'm just a layman.

[monsoon]

Does 750V DC kill someone? I always thought it was the case that DC didn't hurt anyone, but AC did, and that is why Edison originally pushed for a DC-based electrical system. I read that he once did a presentation to prove the dangers of AC by killing an elephant with it.

I might be mixing some of that up, as I'm just a layman.

The only difference between an AC and a DC circuit is that in DC, the polarity stays the same and the current flows in just one direction. In AC, the polarity is reversed every 60th of a second and the current flows back and forth. A 750V AC circuit and a 750V DC circuit will deliver the same amount of energy to your body. If the current is there, it will kill you. Because of the mathematics that I mentioned above, it is more efficient to generate and transport AC power over DC. Remember, a lightening bolt is DC.

Edison pushed for a DC based distribution system because this is what he invented and held patents on. He stubbornly hung onto it despite the fact that Westinghouse's much more efficient AC system is what was adopted by most of the world. One of Edison's tactics was to claim that AC was much more dangerous (which is isn't) by killing animals with AC powered circuits. He also pushed for the first electric chairs to based on AC for similar reasons.

[dubone]

okay, so the only reason DC has a safer reputation, other than Edison's self-serving PR tricks, is that DC happens to be used in low voltage situations like cellphone and laptop chargers.

Whatever they build for LRT and the trolley, I hope they are planning to use the more efficient setup, as electricity will be a large part of the operating costs.

[monsoon]

okay, so the only reason DC has a safer reputation, other than Edison's self-serving PR tricks, is that DC happens to be used in low voltage situations like cellphone and laptop chargers.

Whatever they build for LRT and the trolley, I hope they are planning to use the more efficient setup, as electricity will be a large part of the operating costs.

DC voltage is the only kind of voltage that you can get from a battery. Hence as a result, battery operated devices are going to be DC. Also, electronic swiching technology is based on DC so anything with electronics is also going to be DC. The choice to use DC in these applications is not because of safety, but because that is what you have to used when batteries or electronics are present.

Your hybrid vehicle uses 500V DC because it has to run on batteries. Even normal cars have DC systems because the car has to operate off the battery. However it should be noted that electricty is generated by an Alternator in modern vehicles which produces AC, and then converted to DC because this is more efficient. Older cars used DC generators.

There have been some warnings about people being electricuted in hybrid cars (after accidents) because of the high voltages present, despite these cars being DC based.

http://www.autoblog.com/entry/1234000133047825/

[dubone]

Yeah, under the hood, there is an orange tube filled with the wires that carry electrocution risk. Before today, I thought DC was not dangerous, so I assumed that tube carried the AC power before it got converted to DC for the battery. Now, I realize that it must actually carry the higher voltage DC power to the battery.

(Editted for clarity)

[monsoon]

If it is coming out of the batteries, it is DC. There is no way to directly store AC in a battery. (you are not actually storing electricity in a battery but that is a different discussion) It can be converted to AC but the conversion from DC to AC results in a good deal of power loss and I can imagine they did not do this. (AC to DC is cheap and easy however)

[monsoon]

I did a little looking around and I found conflicting information on the net as to what might be used.

There is a quote by Tober the LRT would operate on dual voltages to be compatable with the Trolley yet one the other hand almost 200K was spent on voltage inverters to make the Trolley compatable with the LRV. (which would suggest the Trolley is DC). Further, the new Houston and Minneapolis systems that don't have to worry about antique trolleys operate on 750V.

I guess we will have to wait and see what they come up with.