Model Railroading > converting new model Kato SD38-2 to old model trucks

Here is the story which began just over three weeks ago.

http://www.trainorders.com/discussion/read.php?3,3698820,3698820#msg-3698820

Once I got my Rapido GMD-1 NAR locos I got interested in adding a couple of SD38-2 units to use with them. Closest commercial models are the Kato SD38-2 models for US Steel. These have the classic body and trucks with composition brake shoes needing only four brake cylinders per truck. Finding one of those models over the last 6 months has proven futile.

While on vacation I stopped at a hobby shop and they had 4 Katos in stock in UP paint. While looking at the models with dynamic brakes I decided the major problem with these two units had clasp type brakes. These were on sale so I grabbed them and set them on the counter for check out.

As a result of the linked post on TO I was able to trade the trucks I needed to a modeler who needed the trucks I had for his NW SD40-2s

Here is what I found about using the older Kato HTC trucks on the newer Kato chassis.

The older trucks had a pin from the bearing plates which raised above the truck sideframe to contact a copper strip in the frame to carry power to the light board. Contact from truck to motor was problematic. Many modelers including myself installed wires soldered to the truck bearing plates through the chassis to the light board which solved the problem. Kato redesigned the chassis to use the same wiring solution modelers were already using. Part of this redesign was to close the slots in the frame the contact pins fit through.

In the new chassis without the contact slots the pins interfere with mounting the old trucks to the new chassis. The solution is to use rail nippers to trim the contact pins flush at the top of the truck sideframes. Once these are trimmed and wires are soldered to the bearing plates the old trucks easily mount to the updated chassis. It took about 90 minutes to modify 4 trucks, install them into two units and install plug in decoders via the light board NMRA 8 pin connection.

It looks like the NAR units will need new headlights front and rear, shortened fuel tanks, different class lights and bell locations and snow plows. I am not sure if the cab steps need to rebuilt as straight steps or not.

This has been a fun project so far.

Posted from Windows Phone OS 7



Edited 1 time(s). Last edit at 04/17/15 21:55 by fbe.

Perhaps there are others who would like to begin their own NAR SD38-2 project, the UP models can still be found. Here's what I bought.

Kato 37-6511 for UPY 833
Kato 37-6512 for UPY 835

Once you get a line on what you need, NAR had 4 units which went to CN where 3 of them are still active, you can likely find more NW modelers looking for clasp brake trucks.

I looked at rebuilding the clasp trucks and decided a swap was far easier. Those clasp trucks need to go to someone who can use them since they are very hard to come buy. Kato is the only company which makes them and so far they have only done them on SD38-2 models. The only places these were found in the prototype were on SD38-2 locos for iron ore roads like DM&IR and B&LE and on a limited number of SD40-2 units for the NW.

Posted from Windows Phone OS 7



Edited 2 time(s). Last edit at 04/17/15 23:08 by fbe.

Here's a thread about the old truck approach that Kato used, also a link in the text to a more extensive description:

http://www.trainorders.com/discussion/read.php?3,1622235