How to lower a locomotive?

[TiVoPrince]

All,
Received a couple of Spectrum DD40AX units (thanks Absnut) and need to know if there is a well documented method to lower the units to correct walkway height. I would like to match the Kato SD40-2 walkway in this "Fast Forty Sandwich".
Also, is there anyone with experience correcting the truck mounted pilots and at what minimum radius? My plan is to use JnJ and/or Alan Curtis TTX flats with these units (like the prototype) so the derailing of truck mounted short shanks on boxcars would be avoided. I suppose I can leave ONE pilot unmodified if necessary, but that just feels so WRONG.
TiVoPrince

 

[Russ Bellinis]

You will probably need a 30" minimum radius for frame mounted couplers to work reliably. You might try mounting a coupler to the frame, and testing it on various radius curves until it causes problems. If there isn't too much overhang on the ends, the frame mounted couplers might work on 22"-24" radius. As far as lowering the locomotive goes, how are the trucks mounted? If they used the typical Bachmann ball joint, I don't think there is an easy way to lower it. If they used an Athearn style drive, the bolsters can be machined to lower the ride height of the locomotive.

 

[TiVoPrince]

Sorry Russ, I forgot to mention that these are NScale units.

I was hoping for some guidance before attacking the split frame and mounting points. While the tank is generally high off the rails I was planning to wrap the fuel tank to build it up to a more realiastic size.

 

[garyn]

So how do the DD40s run? I had the old single motor one many years ago and didn't like them. Does the new 2 motor run reasonably well?

 

[TiVoPrince]

DD40 running

Running quality of the 2 motor version is not all that dissimilar to the Kato SD40-2 that they will be paired with except that the electrical pickup from trucks to frame is poor.
The oval loops over the trucks balance nicely, but do not conduct power to the split frame halves very well. As this area appears to be the material that will need to be removed to lower the walkway the necessary 12 inches to be level with the Kato SD40-2.
My current thinking is to slip a thin pc board on the shell under the walkways to make contact and isolate the current split frame. Electricity would reach the decoder/motor in a similar way to the path on a ConCor SW9.
This would allow the current split frame halves to be used as the Gray/Orange contacts from the decoder.
Still trying to see the "shining path" but this may be as close as I come. Does anyone have the part number for Nscale Clover House PC board ties?

 

[Russ Bellinis]

Is there space inside the body between the frame and body to install a 0-72 screw in the frame? If you can solder one end of two wires to each side of each truck, and put an "eye" on the other end of the wires fastened directly to the two sides of the frame with a solid mechanical connection, you should eliminate your electrical problems. You mentioned that it is n scale, but you didn't mention how the frame is supported by the trucks. Does the frame ride on top of the trucks via bolsters, or does it mount the trucks up inside of the frame? If the frame rides on top of the trucks, I would think a little careful work with a file where the trucks ride would lower it nicely.