Dynamic Braking and EMD 'E' Units.

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Dynamic Braking and EMD 'E' Units.
Posted by BaltACD on Tuesday, February 06, 2018 10:17 PM

I was reading a book on SP passenger service.  Within the book there was a segment on the Shasta Daylight and the power that hauled it.  It stated that it was originally intended that the power for the train would be EMD E-7's however shortly after the train started operating the power was switched to Alco PA's because the PA's had dynamic braking and the E units didn't.

Did EMD offer dynamic braking as a option on any of their E units?

         

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Posted by NorthWest on Tuesday, February 06, 2018 10:59 PM

Dynamic braking was first introduced as an option on the E8.

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Posted by M636C on Tuesday, February 06, 2018 11:13 PM

NorthWest

Dynamic braking was first introduced as an option on the E8.

 
If I recall correctly SP had only one E8 but they had a number of E9s which indeed had dynamic brakes, indicated by a 48" fan in the centre of the units between the radiators.
 
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Posted by Overmod on Tuesday, February 06, 2018 11:47 PM

Only four railroads apparently had E8s with DB (a fifth, Rock Island, bought a demonstrator but may never have used its installed dynamic).  Early ones had a 36" fan, later ones a 48" as on E9s.

I am not a SP expert but I think they used that field loop setup on the E8 dynamic and this was only changed going through the GRIP rebuild program later...

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Posted by jeffhergert on Wednesday, February 14, 2018 5:55 PM

Overmod

Only four railroads apparently had E8s with DB (a fifth, Rock Island, bought a demonstrator but may never have used its installed dynamic).  Early ones had a 36" fan, later ones a 48" as on E9s.

I am not a SP expert but I think they used that field loop setup on the E8 dynamic and this was only changed going through the GRIP rebuild program later...

 

The Rock Island didn't (officially) use dynamic brakes.  Their train handling rules forbid engineers from using them when foriegn power happened to be on RI trains.  The dynamics on engines they bought used were disconnected and on some that were eventually rebuilt, removed entirely.  

Jeff

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Posted by JustWonderin' on Wednesday, February 14, 2018 9:49 PM

jeffhergert

The Rock Island didn't (officially) use dynamic brakes.  Their train handling rules forbid engineers from using them when foriegn power happened to be on RI trains.  The dynamics on engines they bought used were disconnected and on some that were eventually rebuilt, removed entirely.  

Jeff

 

 

Why would using dynamic brakes be banned?  Lack of training on proper usage or something else?

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Posted by NickP on Thursday, February 15, 2018 2:27 AM

JustWonderin'

 

 
jeffhergert

The Rock Island didn't (officially) use dynamic brakes.  Their train handling rules forbid engineers from using them when foriegn power happened to be on RI trains.  The dynamics on engines they bought used were disconnected and on some that were eventually rebuilt, removed entirely.  

Jeff

 

 

 

 

Why would using dynamic brakes be banned?  Lack of training on proper usage or something else?

 Some railroads, like the New Haven and Rock Island considered dynamic brakes a maintenance headache. They ordered new power without dynamics and disconnected the systems on used locos so equipped.

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Posted by CSSHEGEWISCH on Thursday, February 15, 2018 7:00 AM

Until about the 1970's, dynamic braking was considered an expensive option useful for long and heavy grades and not much else.  Many Midwestern roads such as IC, RI, MP and C&NW did not equip their locomotives with dynamic brakes since there was no perceived need for them.

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Posted by Overmod on Thursday, February 15, 2018 9:43 AM

Until the development of effective blended braking, which really inherently depended on developments in practical electronics, many of the principal uses of 'cost-effective' dynamics on E units (and other passenger power) would be severely limited and perhaps even dangerous.  About the only 'good' use would be retarding heavy passenger consists down long or severe grades -- there was a dramatic Steinheimer picture accompanying a poem in an early-'70s issue of Trains that shows a good example of a situation that would likely benefit from good dynamic.  But the fun involved with jockeying throttle and contemporary EMD dynamic in, say, repeated commuter stops while modulating the train brake is not something I suspect most commuter engineers would enjoy.  

 

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Posted by beaulieu on Thursday, March 01, 2018 12:34 AM

Railroads also used to allow Power Braking for smooth stops. Now it is forbidden on freight trains at least.

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