Rohr cars and it's dictivtive sounds

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Rohr cars and it's dictivtive sounds

Postby jerryinva » Wed Mar 05, 2008 11:10 am

So, what gives the Rohr cars that distinctive whine?
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Postby tommyboy6181 » Wed Mar 05, 2008 11:37 pm

The whine comes from the General Electric AC traction motors (3 phase, asyncronous with GTO type inverters). The 1000 series were the first WMATA fleet to have these installed as part of their Brentwood mid-life rehab back in the 1990's. The reason is simple...AC motors dont have brushes or choppers to deal with and that makes the motor design simpler and with less parts, better reliability. I'm sure someone can add more details about the motors like Mike Morris or 1 of the people from the shops.

If you want to hear a really loud AC motor, you should see the Rohr rehabs that BART uses in San Francisco. Those use AdTranz motors (1507C with water cooling) and that takes the cake for the loudest whine.
Hear that here: http://www.youtube.com/watch?v=resCQsiAWio
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Postby jerryinva » Thu Mar 06, 2008 8:17 am

Thanks for the answer! As rundown and smelly as the Rohr cars are...I love that sound...
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Postby tommyboy6181 » Thu Mar 06, 2008 11:43 pm

No problem. The reason you will hear the whine is because of the high speed electronic inverters used in the motors. Basically power will go through the inverters to help start the motor hence the whine. From there, the motors go into a 3 phase asychronous mode (same on all the AC cars). Thats probably the best answer to give without getting into a whole long technical explanation.

As for the inverters themselves, GTO was the only type available in the mid 1990's. They have since been phased out in favor of IGBT based systems from the late 1990's onward for new systems simply due to advances in technology. Also, GTO requires more fluid to work with and Breda has several cities where the inverters use a R-7 Freon bath.

The Rohr cars are the only fleet that use GTO inverters with the GE motors while the Breda rehabs/Alstom cars (Alstom ONIX propulsion) and CAF cars (Bombardier MITRAC propulsion) all use an IGBT inverter system.

I did find a clip of the Shenzhen Metro that uses the Bombardier MITRAC system that sounds virtually identical to the Rohr cars, just with current technology, and 1500 volts power compared to 750.
Shenzhen: http://www.youtube.com/watch?v=F26NMKHd7fQ
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Postby Robert Paniagua » Mon Mar 17, 2008 8:16 pm

Not to mention the Rohrs actually sound exactly like the MBTA's #3 Red Line 01800-series cars when stopping and starting such as the video linked below.

http://www.youtube.com/watch?v=1iLmeeF6FZY
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Postby tommyboy6181 » Mon Mar 17, 2008 9:48 pm

You would be right since the 01800's, Rohr cars, SF Muni, and most of the LA Breda cars for the red line use the same GE motors.
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Postby jerryinva » Tue Mar 18, 2008 2:48 pm

I imagine the Rohr cars are becoming harder to get parts for...and a pain to work on, especially the electronics, due to the larger components of the 1970's.
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Postby Sand Box John » Fri Mar 21, 2008 8:54 am

"jerryinva"
I imagine the Rohr cars are becoming harder to get parts for...and a pain to work on, especially the electronics, due to the larger components of the 1970's.


The Rhor cars were totally rehabilitated in the mid 1990s. All of the 1970 vintage electronic components that were in those cars are either in a land fill or have been recycled.
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Postby Mike Morris » Tue Mar 25, 2008 6:00 pm

Tommy is right on the money.


The Rohrs can be a challenge to work on due to the age. The HVAC system especially above the drain pains in the front of the car still use ancient electronics. The blower motors and assembly are very heavy and make a lot of noise. That system was to be rehabbed by TTA but only 1 pair got done.

A lot of the fasteners used on that train are no longer made. Example of this are the fasteners holding up the ceiling panels in the front and the side light bezels.

I actually have an odometer from one if someone wants one. No longer used.

The cars are suffering from stress cracks in the bodies. They can be seen usually in front of the front doors.
Despite their age-they and the 4Ks are the most reliable cars in the system. Most of the HVAC stuff is really in need of replacement though.
A lot of operators don't like to use them because the master controller is really tough to operate in terms of arm strength. However in bad weather when used in manual they and the 6Ks are the favorite.
Train is very well designed. Never hear or seen one derail unlike that POS 5K train. 1Ks can be loud but I have heard 5Ks just as loud. And in a collision I would rather be in a ROHR than a CAFE any day of the week.
For some odd reason they don't like to communicate with 4Ks when mixed and used on the operating side.

I really hope one set is kept around when the 7K replace them. A really neat train. I will try to grab all of the sevice manuals so people can have them. They are quite think and complex. The HVAC one rivals a dealer service manual for your automobile.
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Postby jerryinva » Tue Mar 25, 2008 8:51 pm

Mike Morris wrote:The Rohrs can be a challenge to work on due to the age. The HVAC system especially above the drain pains in the front of the car still use ancient electronics. The blower motors and assembly are very heavy and make a lot of noise. That system was to be rehabbed by TTA but only 1 pair got done.


I notice that the Rohr's leak a lot from the front ceiling of the car when it is really humid in the summer.

There are times when I look at the cars I notice parts that look like they were manufactured as replacement...

Did the red lights above the doors on the inside of the cars ever light up?
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Postby WMATAGMOAGH » Wed Mar 26, 2008 4:58 am

jerryinva wrote:
Mike Morris wrote:The Rohrs can be a challenge to work on due to the age. The HVAC system especially above the drain pains in the front of the car still use ancient electronics. The blower motors and assembly are very heavy and make a lot of noise. That system was to be rehabbed by TTA but only 1 pair got done.


I notice that the Rohr's leak a lot from the front ceiling of the car when it is really humid in the summer.

There are times when I look at the cars I notice parts that look like they were manufactured as replacement...

Did the red lights above the doors on the inside of the cars ever light up?


I think I've seen those lights work once on a Rohr.

In Paris, the newer trains all have lights above the doors to indicate when the door closes. But the lights come on over the doors on both sides of the train, regardless of which side is actually open! Maybe they could get it to work on the Rohrs if they programmed it that way. The new MF2000 cars in Paris only have the light flash over actually open doors.
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Postby Sand Box John » Wed Mar 26, 2008 7:46 am

"jerryinva"
I notice that the Rohr's leak a lot from the front ceiling of the car when it is really humid in the summer.


The leaking of the AC units at the cab ends of the cars has been happening sense the first summer after WMATA opened phase I in 1976.
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Postby Robert Paniagua » Wed Mar 26, 2008 7:55 am

Oh wow, and they've never done something to fix those AC leaks on the 1ks? Well, at least they will be pulled from service in a few years with the 7ks just like the Boeing Vertol LRVs on the MBTA Green Line which were made at the same exact time as the Rohrs.
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Postby Sand Box John » Wed Mar 26, 2008 10:00 am

"Robert Paniagua"
Oh wow, and they've never done something to fix those AC leaks on the 1ks? Well, at least they will be pulled from service in a few years with the 7ks just like the Boeing Vertol LRVs on the MBTA Green Line which were made at the same exact time as the Rohrs.


Totally different animal.

Mike Morris can likely shed more on the issue about the water leaking from the AC units on the 1k cars. From where I sit, it appears the design of the condensation collection pan and drain line in the AC units were not design correctly in the first place.
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Postby Robert Paniagua » Wed Mar 26, 2008 11:58 am

Oh Ok, thanks, I'm sure he'll have an answer to that leak issue.
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