N Scale of Nevada retroframe for Kato U25B ?

[scaro]

Hi

I am wondering why Kato did a retroframe for the Atlas/ Kato U25B ? 

Is the original off in some way?

Regards, Ben

[daniel_leavitt2000]

I'm pretty sure NSN just milled a pocket for a wired DCC decoder a la Aztec. They did a bunch of chassis... SD40/45 and U30C/C30-7 I believe.

The only retro frame that changed anything mechanically was the one for the first generation GP7/9 monstrosity to spread the wheelbase out a bit.

[nickelplate759]

NSN had a whole line of retro-frames.  For all the ones I have seen, they were all cast by NSN, not modifications of original frames. One selling point was that their castings were heavier than the original frames.  Alas, they were also a lot softer, so getting and keeping them straight was a challenge.

Besides the stretch frame for the Atlas/Kato GP7/9, I have or had a frame to convert the Atlas/Kato GP9 to a passenger unit, a frame to convert an Atlas/Roco GP30 to an Atlas/Kato drive, and a frame for the Con-Cor/Roco C636.  They also made frames for Rivarossi 4-6-2, and I think for the 2-8-2 as well.  Probably others as well.

[peteski]

NSN had a whole line of retro-frames.  For all the ones I have seen, they were all cast by NSN, not modifications of original frames. One selling point was that their castings were heavier than the original frames.  Alas, they were also a lot softer, so getting and keeping them straight was a challenge.

Besides the stretch frame for the Atlas/Kato GP7/9, I have or had a frame to convert the Atlas/Kato GP9 to a passenger unit, a frame to convert an Atlas/Roco GP30 to an Atlas/Kato drive, and a frame for the Con-Cor/Roco C636.  They also made frames for Rivarossi 4-6-2, and I think for the 2-8-2 as well.  Probably others as well.

From what I recall, the Retroframes originated with the chassis with modified wheelbase to attempt to "fix" the ill-conceived stretched Atlas GP9s and GP7s.  While it made the model look better, it still didn't look right. But it was the best thing that could be done to work with the stretched shell.

Then others were made. Like George says, the extra weight of the soft pewter alloy was the selling point.  They were quite a bit heavier than the original white-metal framed.  But I never liked how soft they were.

[bobdobbs]

http://www.aztectrains.com/dccframes.html

Go with the Aztec frame. 

It is the OEM, not a copy.  never had trouble, John does an awesome milling job and turn around is usually a week living in Cali.

[johnb]

NSN had a whole line of retro-frames.  For all the ones I have seen, they were all cast by NSN, not modifications of original frames. One selling point was that their castings were heavier than the original frames.  Alas, they were also a lot softer, so getting and keeping them straight was a challenge.

Besides the stretch frame for the Atlas/Kato GP7/9, I have or had a frame to convert the Atlas/Kato GP9 to a passenger unit, a frame to convert an Atlas/Roco GP30 to an Atlas/Kato drive, and a frame for the Con-Cor/Roco C636.  They also made frames for Rivarossi 4-6-2, and I think for the 2-8-2 as well.  Probably others as well.

NSN also made retroframes for Bachmann diesels, the extra weight made a huge improvement in performance

[Spades]

Yes they did. http://www.ebay.com/itm/N-Scale-of-Nevada-Retro-Frame-Kit-RRRU25-for-Atlas-Kato-U25B-N-Scale-/232096710551?hash=item360a0abf97:g:EAgAAOSwCGVX6tun

G

[scaro]

About thirty years ago I had one of the NSN retroframes for the GP7.   

What wheelbase did it actually have? 

The original Atlas was based on the RS3 so that would have been 30' and a real GP7 would be 31' wheelbase. I had some idea the NSN frame was too long for a real GP7, but matched the elongated Atlas shell.

Ben

[peteski]

About thirty years ago I had one of the NSN retroframes for the GP7.   

What wheelbase did it actually have? 

The original Atlas was based on the RS3 so that would have been 30' and a real GP7 would be 31' wheelbase. I had some idea the NSN frame was too long for a real GP7, but matched the elongated Atlas shell.

Ben

I don't remember the details, but you described the problem quite well: The shell of Atlas Geeps was too long for the wheelbase. The retroframes actually stretched the wheelbase to mitigate that visual disaster.  The trucks ended up being closer to the ends of the model which while actually incorrect  looked better than the original loco with large overhangs on the ends.

[thomasjmdavis]

Probably others as well.

I have several for the original Kato F units.  Also made one for the Atlas/Roco FA1, IIRC.  I think that one for the Atlas.Kato GP may have been the first they did (the first I remember seeing, at any rate), but the availability of small decoders created a demand for replacement frames for many of the high quality, non DCC drives.