MTA Purple Line Bethesda - New Carrollton Light Rail

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tommyboy6181
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Re: Washington Metro Purple line

Post by tommyboy6181 »

srepetsk wrote:The Washington Post reported today that CAF cars are included in one of the bidder's proposals for the Purple Line: https://www.washingtonpost.com/local/tr ... &tid=ss_tw" onclick="window.open(this.href);return false;
Reading the article, all the reporter did was basically blast CAF for their cars. Now, we all have to remember that CAF's Metro contract was their very first in the US back in the late 90's/early 00's. CAF didn't even assemble the cars- that was done by AAI which was bought by Alstom. CAF did the design and engineering. Combine that with Metro wanting the cars yesterday and that led to the product they received.

Now with the LRV project, I would think this is going to be a better result. CAF has owned their Elmira factory for years now, has a standardized product line for their streetcar and light rail vehicles, and now provide many of their own components including communication systems, signalling and propulsion. This was not the case back when the Metro contract was completed. An example of this is in Cincinnati and Kansas City where both are using the standard CAF Urbos 3 streetcar with propulsion and inveters provided by sister company CAF Power & Automation (was known as Trainelec before CAF purchased the company).

Cincinnati: https://www.youtube.com/watch?v=-megXn1zvtY" onclick="window.open(this.href);return false;
Helsinki: https://www.youtube.com/watch?v=VDVui0Mm_QM" onclick="window.open(this.href);return false;

A little background on the motors themselves. CAF usually has the motors for their propulsion system built by either TraktionsSysteme Austria or by ABB. Both manufacturers have also built motors for Alstom, Bombardier, Siemens, Vossloh and others.

I doubt that this contract would be a disaster. But in any major project like that, close supervision and communication along with quality engineering, assembly and testing are essential to producing a reliable product.
Gotta love Alstom. Every year on opening day of hunting season, it is a paid holiday! :wink:

Jeff Smith
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Re: MTA Purple Line Bethesda - New Carrollton Light Rail

Post by Jeff Smith »

Progressive Railroading

SNIPS:
Maryland chooses team to build, maintain Purple Line light-rail route
...
The line will have 21 stations and will run from New Carrollton to Bethesda, Md.

With an expected $1.36 billion in fare revenue, along with local and federal contributions to the project, the final cost for the state will be $3.3 billion over 36 years, according to a press release issued by Hogan's office.
...
The Maryland Transit Administration (MTA), which will oversee construction, will give Purple Line Transit Partners full notice to proceed on the project at the financial close, with construction starting in late 2016.

The line is expected to open for service in spring 2022.
...
Next stop, Willoughby
~el Jefe ("Jeff Smith Rules") :: RAILROAD.NET Site Administrator/Co-Owner

farecard
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Re: MTA Purple Line Bethesda - New Carrollton Light Rail

Post by farecard »

I saw some mention that under Hogan's cuts, the Purple Line will *not* serve Silver Spring station at all.
I hope this was an April Fool but.......

Tell me it ain't so, Joe...

(After all that's the situation on the Silver Line; it won't serve IAD, only the IAD parking lot.)

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Nicholas Chen
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Re: MTA Purple Line Bethesda - New Carrollton Light Rail

Post by Nicholas Chen »

Sorry, doesn't seem to be a joke. The purple line won't go directly to the Metro station but, is supposed to be level with the transit center according to this Greater Greater Washington post.

scratchy
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Re: MTA Purple Line Bethesda - New Carrollton Light Rail

Post by scratchy »

my understanding is it wouldn't be that much of a walk, it'd better connect with the buses, and be less a few escalators to break down.

MCL1981
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Re: MTA Purple Line Bethesda - New Carrollton Light Rail

Post by MCL1981 »

This boondogle will still be at the Silver Spring metro. Just on the opposite side of the transit center.

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JDC
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Re: Washington Metro Purple line

Post by JDC »

GGW had a story about the cars that will populate the Purple Line: http://greatergreaterwashington.org/pos ... -railcars/
Living in Springfield, VA; Working at Half & L, DC.

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Re: Washington Metro Purple line

Post by farecard »

What do we know about the traction power system?
It must be VFD's driving polyphase motors, but how big & what voltage is the catenary?

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Sand Box John
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Re: Washington Metro Purple line

Post by Sand Box John »

"farecard"
What do we know about the traction power system?


Content tension overhead over head catenary with underground feeder bus connected to the primary messenger at multiple point between substation. 8 mainline substations, 1 at 4,000 KW, 7 at 2,000 KW, 2 yard substation, Lyttonsville 1 at at 2,000 KW, Glenridge yard 2, 1 at 2,000 KW and 1 at 500 KW.

It must be VFD's driving polyphase motors, but how big & what voltage is the catenary?

Rolling stock is coming from CAFs light rail catalog.

1,500 VDC.
John in the sand box of Maryland's eastern shore.

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Re: Washington Metro Purple line

Post by farecard »

Sounds reasonable. BART initially got into deep dodo with their 1KV motors arcing, but that was in an era of DC motors.
There is no such issue with polyphase induction motors; they regularly come in voltages well exceeding 5KV.

Do we know what a train draws in traction and hotel loads?

I suspect they will end up upgrading the power supply at some point; I only hope "Operation Cheap" is leaving footprint space for such.

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Sand Box John
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Re: Washington Metro Purple line

Post by Sand Box John »

"farecard"
Sounds reasonable. BART initially got into deep dodo with their 1KV motors arcing, but that was in an era of DC motors.
There is no such issue with polyphase induction motors; they regularly come in voltages well exceeding 5KV.


Contact wire voltage is not an issue. The AC voltage out of the veritable frequency inverts is configured to the voltage of induction traction motors.

There were 2 contact wire voltage options were 750 VDC and 1,500 VDC, the 750 VDC option required 7 more substation all rated at 2,000 KW. The 1,500 VDC substations are rated at 4,000 KW, not the 2,000 KW I stated in the post above, the yard substations are 800 KW at Lyttonsville and 1,500 KW at Glenridge.

Do we know what a train draws in traction and hotel loads?

My best guess would be somewhere in the neighborhood 1,000 to 1,200 amps under full load.

I suspect they will end up upgrading the power supply at some point; I only hope "Operation Cheap" is leaving footprint space for such.

All of the substations will built with 2 transformer rectifier packages rated at 2,000 KW each. The switchgear is to be rated at 4,000 KW. I could find nothing in the documents about provisions for a third transformer rectifier package pad.
John in the sand box of Maryland's eastern shore.

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Re: Washington Metro Purple line

Post by farecard »

Sand Box John wrote: Contact wire voltage is not an issue. The AC voltage out of the veritable frequency inverts is configured to the voltage of induction traction motors.
I have never seen a VFD with transformers for voltage change. Part of their attraction is not having expensive iron and copper; just MOSFETS.
There were 2 contact wire voltage options were 750 VDC and 1,500 VDC, the 750 VDC option required 7 more substation all rated at 2,000 KW. The 1,500 VDC substations are rated at 4,000 KW, not the 2,000 KW I stated in the post above, the yard substations are 800 KW at Lyttonsville and 1,500 KW at Glenridge.
1500 VDC makes more sense for any new design; the only issue is greater standoff distance needed, and that's really only an issue in tunnels.

Do we know what a train draws in traction and hotel loads?
My best guess would be somewhere in the neighborhood 1,000 to 1,200 amps under full load.
I'll be interested in real specs when they are released.

I suspect they will end up upgrading the power supply at some point; I only hope "Operation Cheap" is leaving footprint space for such.
All of the substations will built with 2 transformer rectifier packages rated at 2,000 KW each. The switchgear is to be rated at 4,000 KW. I could find nothing in the documents about provisions for a third transformer rectifier package pad.
Sigh....

gokeefe
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Re: Washington Metro Purple line

Post by gokeefe »

Just be happy its getting built. As long as it actually runs it will be unstoppable. There's plenty of money in the coffers for future upgrades should they be necessary. The only thing I would be watching for is if the system specs (transmission voltages in particular) would really hold back expansion. I haven't gotten that impression at all.
gokeefe

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Sand Box John
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Re: Washington Metro Purple line

Post by Sand Box John »

"farecard"
1500 VDC makes more sense for any new design; the only issue is greater standoff distance needed, and that's really only an issue in tunnels.


Standoff is not as big an issue as you might think. Most of the primaries on the top of utility poles in PEPCO territory are 4.43KV each for a total of 13.3 KV. Over here in Delmarva Power territory they are 4.1 each for a total of 12.3 KV. Delmarva Power is preparing to upgrade the primaries in front of my house without any changes to the size of insulators to 8.33 each for at total of 25 KV.
John in the sand box of Maryland's eastern shore.

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Re: Washington Metro Purple line

Post by farecard »

I'm quite familiar with PEPCO. Their primary distribution is as you say, 13KV.
Their feeders, at the top of some pole lines are 66KV; they have distinctive foot+-tall insulators.
[A feeder goes between a major yard such as Takoma [38.969713, -76.997893] or Metzerott Rd [39.005522, -76.957424] & multiple local substations.]
You may see some 33KV feeders as well, but many seem to be abandoned in place. They have insulators slightly larger than the primaries.

The cat standoff distance really becomes an issue only when in tunnels. Higher ceilings co$t more there.

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