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Aerotrain Dynamic Brakes

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Aerotrain Dynamic Brakes
Posted by mvlandsw on Saturday, May 18, 2019 7:59 PM

Did the Aerotrains have dynamic braking? I'm installing an ESU sound decoder in one and I wonder if the dynamic braking sound should be active or muted.

Thank You,

Mark Vinski

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Posted by gmpullman on Saturday, May 18, 2019 8:34 PM

Of all the details I've read about Aerotrain, I have never seen any mention of dynamic brakes. With the lightweight construction of the carbodies the thought was that there probably wouldnt be any need for dynamics.

Propulsion was through a 12 cylinder EMD 567C coupled to a D-15E generator and a pair of D-37 traction motors on the front truck. There were two auxiliary 6 cylinder 6-71 Detroit diesels mounted in the nose supplying 440V. 3Ø "hotel" power.

Regards, Ed

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Posted by tstage on Saturday, May 18, 2019 9:05 PM

mvlandsw
I'm installing an ESU sound decoder in one...

Mark,

I assume you went with the Select Micro?  Should you ever want to add gyralighting to the taillights of the observation car, let me know.  I can tell you what I did.

Tom

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Posted by "JaBear" on Saturday, May 18, 2019 10:50 PM

"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."

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Posted by SPSOT fan on Saturday, May 18, 2019 10:53 PM

I would assume the LTW2 lacked dynamic breaks, as there really wasn’t reason for them. Most of their lives where spent in Rock commuter service in a very flat part of the country, and the cars were very light to begin with. You may want to confirm with somewhere else, I’m not a Aerotrain expert, but I dought it had them.

Regards, Isaac

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Posted by dehusman on Sunday, May 19, 2019 7:56 AM

SPSOT fan

I would assume the LTW2 lacked dynamic breaks, as there really wasn’t reason for them. Most of their lives where spent in Rock commuter service in a very flat part of the country, and the cars were very light to begin with.  

They ended up on the Rock Island, but that's not what they were built for or where they started.  They started as demonstrators and operated on several different railroads, notable the PRR, UP and ATSF, all railroads that did have substantial grades and as demnstrators they would have had all the bells and whistles in order to show potential customers what they could do.  

Having said that, the dynamic brakes would probably not sound anything line modern dynamic brakes because they were probably way smaller than a "standard" dynamic brake grid (only supporting one truck) and being a very light train, would probably not have been used that much.

Dave H. Painted side goes up. My website : wnbranch.com

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Posted by Overmod on Monday, May 20, 2019 7:34 AM

There are very good reasons why a lightweight trainset with relatively heavy engine would benefit from DB even on just two axles in commuter service, on the flat or not. If I remember correctly the variation in air-brake proportioning from light to heavy passenger loading was substantial, but at least the initial arrangements to provide it more than a little rudimentary.  Proper use of DB would get rid of a LOT of potential wheelslide on the buses at higher speed.  In fact a good extended-range dynamic would probably be useful in a number of kinds of bad weather, where for example low-speed air braking might cause substantial judder and "NVH"

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Posted by mvlandsw on Monday, May 20, 2019 2:44 PM

Extended range dynamic braking was probably not available in the Aerotrain era. At least none of the locomotives I worked with had it until the late 70's or early 80's.

What is "NVH" ?

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Posted by Overmod on Monday, May 20, 2019 7:50 PM

mvlandsw

Extended range dynamic braking was probably not available in the Aerotrain era.

probably not, although I recall some PCC cars having an equivalent function down to low speed.  I was just noting how that would be valuable with the light train.

What is "NVH"?

Noise, vibration and harshness.  

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Posted by M636C on Friday, May 24, 2019 7:05 AM

Quite apart from the links above from the Bear, the MTH model in O gauge has dynamic brakes.

https://www.mthtrains.com/sites/default/files/catalog_files/2019_v_2/index.html

Go to page 46.

Note the 36" dynamic brake fan inset into the "hump" behind the cab.

Peter

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Posted by Backshop on Friday, May 24, 2019 7:17 AM

M636C

Quite apart from the links above from the Bear, the MTH model in O gauge has dynamic brakes.

https://www.mthtrains.com/sites/default/files/catalog_files/2019_v_2/index.html

Go to page 46.

Note the 36" dynamic brake fan inset into the "hump" behind the cab.

Peter

 

Sure that isn't the radiator cooling fan?  I don't see any grids.

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Posted by M636C on Monday, May 27, 2019 7:29 AM

The radiator on the LWT-12 is at the rear end as indicated by the grilles either side of the body and given the effort to keep the cost down, the cooling fan was probably mechanically driven as it was in most switchers. So the LWT-12 probably didn't have a companion alternator to drive an AC cooling fan. A single 36" fan is unlikely to be enough to cool a 1200 hp engine, given that a 1500 HP F unit needed four such fans.

The grilles behind the cab would provide enough airflow for the small resistance grids required for two traction motors.

So I don't think there is any doubt that the single fan is for the dynamic brakes.

Peter

 

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Posted by jeffhergert on Tuesday, May 28, 2019 4:51 PM

Besides the two demonstrator units, there was a third LWT-12 built.  Ordered by the Rock Island with a Talgo train set that for a time was called the Jet Rocket.  The RI didn't use dynamics so I'm sure the one they ordered wouldn't have had them.  If the originals did, the RI would've disabled them.  The RI ordered unit also had a blomberg truck instead of a flexcoil truck.  It was scrapped in 1966 when the original demonstator units went to the musuems.

Originally all sets were going to be used in intercity service, at least on their Chicago to Peoria runs.  They didn't last long in that role because the ride quality was bad and placed into Chicago commuter service.

Jeff

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