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Maximum curve radius......

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Maximum curve radius......
Posted by txhighballer on Tuesday, May 26, 2009 6:42 PM

What is the sharpest curve an SD 50 and an SD40-2 will get around coupled to another unit or coupled to a train?  Since they are very close in overall length I would think the radius would be the same. Thanks in advance  for the help!

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Posted by timz on Tuesday, May 26, 2009 6:58 PM

SD40-2 oper manual says 25 degrees for two units (if no footboards) and 16 deg for a unit coupled to a 50-ft car.

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Posted by mudchicken on Tuesday, May 26, 2009 10:12 PM

timz

SD40-2 oper manual says 25 degrees for two units (if no footboards) and 16 deg for a unit coupled to a 50-ft car.

Coupling to anything much beyond a 12 degree 30 minute curve would be a recipe for bypassed knuckles. EMD's were so much more forgiving than GE's and god forbid you had a passenger unit.

The only SD50's I  ever saw on Santa Fe were demo/test units or foreign road units. Their coupler throws were more restrictive. Don't automatically assume they are the same....it's a function of coupler throw, distance from the center pin to the coupler, draft gear and trucks.

Footboards were legal when SD40-2's were first introduced?

EDIT:

25 Degree Curve = 231.01 Feet of Radius

16 Degree Curve = 359.26 Feet of Radius

12 Degree 30 Minute Curve = 459.28 Feet of Radius

 

REAL RAILROADERS DON'T NEED NO STINKIN' RADIUS!Evil

(Corollary: Arc definition is for lowlife highway surveyors and engineersMischief)

Mudchicken Nothing is worth taking the risk of losing a life over. Come home tonight in the same condition that you left home this morning in. Safety begins with ME.... cinscocom-west
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Posted by erikem on Thursday, May 28, 2009 12:26 AM

mudchicken

timz

SD40-2 oper manual says 25 degrees for two units (if no footboards) and 16 deg for a unit coupled to a 50-ft car.

Coupling to anything much beyond a 12 degree 30 minute curve would be a recipe for bypassed knuckles. EMD's were so much more forgiving than GE's and god forbid you had a passenger unit.

 

That would explain why the D&RGW used only four axle power on the La Veta Pass line, sharpest curves are 15 or sixteen degrees. 

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Posted by oltmannd on Thursday, May 28, 2009 6:34 AM

For an SD50, it's 29 single, 24 MU.  Don't know the "coupled to 50' box car".

As a practical matter, Conrail did have trouble with the pilot plows on SD40-2s striking each other on what was supposed to be a 12 degree curve connecting the Harrisburg Line to the Lurgan Branch, so....

"your mileage may vary"

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by Railway Man on Thursday, May 28, 2009 8:08 AM

erikem

mudchicken

timz

SD40-2 oper manual says 25 degrees for two units (if no footboards) and 16 deg for a unit coupled to a 50-ft car.

Coupling to anything much beyond a 12 degree 30 minute curve would be a recipe for bypassed knuckles. EMD's were so much more forgiving than GE's and god forbid you had a passenger unit.

 

That would explain why the D&RGW used only four axle power on the La Veta Pass line, sharpest curves are 15 or sixteen degrees. 

 

Not so.  D&RGW has 16 degree curves on the main track on the Moffat.  D&RGW, SP, and now UP run every type of six-axle power they own around those curves -- and the DDA40X too.  The Veta Pass restriction was to avoid having to put in a lot of new ties.  Six-axle power uses up the life that's left in an old tie on a sharp curve a whole lot faster than four-axle power.

RWM


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Posted by erikem on Friday, May 29, 2009 12:25 AM

RWM,

 Thanks for the correction.

- Erik
 

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