Sorry for the length and technical minutia of this post, it may be a great treatment for insomnia....
Kicking some ideas around regarding this brass KTM RS2 unit. I received some other follow-on purchases including an Athearn can motor with dual flywheels, a Digitrax DN136D DCC decoder, and an AHM RS2 (bought for potential donor parts). Yeah, I do want to make this a DCC unit to run on my layout, so the decoder was a no-brainer. However, before wiring up the decoder, I'm having second thoughts about the original motor. The fact that I have a nice quiet unattached dual flywheel unit is eating at me.
Despite my attempts to dampen the noise of this Japanese motor, it's still quite loud. The Athearn motor was a decent deal on evil-bay and I bought it soon after winning the auction for the EL RS2, after reading about the KTM units' reputation for annoyingly noisy operation. So, I've been looking at real estate and the potential for re-use of the original gear towers. Here's a shot of the can motor laid into the center of the KTM chassis.
In order to fit the Athearn motor in the motor mount bracket (the removable section in the center of the locomotive), if the replacement is going to happen I'm going to have to notch out the front and rear of the bracket to allow the motor to drop so the output shafts from the motor are at the same horizontal level as the gear tower shafts. My rough guess on the amount of drop necessary is 0.2 inches to get completely level from the gear towers through the center of the motor.
Here's a shot with the bracket removed to better illustrate a better alignment for the output shafts. The second shot shows that I'll probably have to cut into the runway structure to allow the flywheels to spin unencumbered.
Next problem - adapting output gearing from the can motor to the truck gear towers, and I think I've figured out something that might work - which gets me to the answer to the question "Why in the world would Todd buy an AHM loco?"
I had a "GP18" Lehigh Valley AHM unit as a kid - it actually came with a dummy unit and I loved running those until numerous derailings and falls rendered each a total loss. All plastic with a couple of strategically located lead weights, not prototypical, but back in those days my budget was quite limited, so Tyco and AHM were very popular producers of my rolling stock. One of the great things about our hobby now is that the quality of rolling stock and locomotives is miles better than in the late 1970's, but that crappy stuff still makes it to swap meets and model railroading shows, and there's still a ton of it on ebay. All I really wanted from the AHM RS2 were potentially the motor, output shafts, trucks and gear towers in case I wanted to swap those out too. The model I picked up is a Southern Pacific RS2, which, by the way, the SP never rostered. The thing was coated in dust and debris, but after running it a bit the motor started working decently. We'll set that aside for now.
The Athearn motor was shipped with two output knuckles that accept Athearn's standard dogbone shaft, which they sell in a bunch of different lengths. The problem, however, is how to interface with the truck gear towers, and that's where I think I can use some of the AHM parts. In the photo below, I've removed the standard Athearn ouput knuckle sleeve, and connected the universal knuckle to ball and pin shaft from the AHM unit that adapts to the Athearn knuckle in each flywheel, and then the output knuckle (next item to the right in the photo) from the AHM motor that I'm planning on either drilling out to fit the shaft on the gear tower after I remove the TKM rubber universal joint, or buying one predrilled to the right size. I think with some good measurements it looks like I can buy an output knuckle that will fit the gear tower shaft and the AHM ball.
If I look at the total length between the ends of the AHM output knuckles on either side of the motor, I come up with 4.75 inches in total length. From gear to gear on each gear tower, the total distance is 4.9 inches, so there's a little room for slop as the trucks rotate through curves. The end result of all of this hypothetical nonsense is that I believe it would be possible to integrate the can motor to the existing gear towers, and it becomes more and more likely that I may eventually get out the Dremel and start making modfications rather than just do a straight conversion to DCC on this little beast.
Kicking some ideas around regarding this brass KTM RS2 unit. I received some other follow-on purchases including an Athearn can motor with dual flywheels, a Digitrax DN136D DCC decoder, and an AHM RS2 (bought for potential donor parts). Yeah, I do want to make this a DCC unit to run on my layout, so the decoder was a no-brainer. However, before wiring up the decoder, I'm having second thoughts about the original motor. The fact that I have a nice quiet unattached dual flywheel unit is eating at me.
Despite my attempts to dampen the noise of this Japanese motor, it's still quite loud. The Athearn motor was a decent deal on evil-bay and I bought it soon after winning the auction for the EL RS2, after reading about the KTM units' reputation for annoyingly noisy operation. So, I've been looking at real estate and the potential for re-use of the original gear towers. Here's a shot of the can motor laid into the center of the KTM chassis.
In order to fit the Athearn motor in the motor mount bracket (the removable section in the center of the locomotive), if the replacement is going to happen I'm going to have to notch out the front and rear of the bracket to allow the motor to drop so the output shafts from the motor are at the same horizontal level as the gear tower shafts. My rough guess on the amount of drop necessary is 0.2 inches to get completely level from the gear towers through the center of the motor.
Here's a shot with the bracket removed to better illustrate a better alignment for the output shafts. The second shot shows that I'll probably have to cut into the runway structure to allow the flywheels to spin unencumbered.
Next problem - adapting output gearing from the can motor to the truck gear towers, and I think I've figured out something that might work - which gets me to the answer to the question "Why in the world would Todd buy an AHM loco?"
I had a "GP18" Lehigh Valley AHM unit as a kid - it actually came with a dummy unit and I loved running those until numerous derailings and falls rendered each a total loss. All plastic with a couple of strategically located lead weights, not prototypical, but back in those days my budget was quite limited, so Tyco and AHM were very popular producers of my rolling stock. One of the great things about our hobby now is that the quality of rolling stock and locomotives is miles better than in the late 1970's, but that crappy stuff still makes it to swap meets and model railroading shows, and there's still a ton of it on ebay. All I really wanted from the AHM RS2 were potentially the motor, output shafts, trucks and gear towers in case I wanted to swap those out too. The model I picked up is a Southern Pacific RS2, which, by the way, the SP never rostered. The thing was coated in dust and debris, but after running it a bit the motor started working decently. We'll set that aside for now.
The Athearn motor was shipped with two output knuckles that accept Athearn's standard dogbone shaft, which they sell in a bunch of different lengths. The problem, however, is how to interface with the truck gear towers, and that's where I think I can use some of the AHM parts. In the photo below, I've removed the standard Athearn ouput knuckle sleeve, and connected the universal knuckle to ball and pin shaft from the AHM unit that adapts to the Athearn knuckle in each flywheel, and then the output knuckle (next item to the right in the photo) from the AHM motor that I'm planning on either drilling out to fit the shaft on the gear tower after I remove the TKM rubber universal joint, or buying one predrilled to the right size. I think with some good measurements it looks like I can buy an output knuckle that will fit the gear tower shaft and the AHM ball.
If I look at the total length between the ends of the AHM output knuckles on either side of the motor, I come up with 4.75 inches in total length. From gear to gear on each gear tower, the total distance is 4.9 inches, so there's a little room for slop as the trucks rotate through curves. The end result of all of this hypothetical nonsense is that I believe it would be possible to integrate the can motor to the existing gear towers, and it becomes more and more likely that I may eventually get out the Dremel and start making modfications rather than just do a straight conversion to DCC on this little beast.
Check out my "Rainbows in the Gorge" website: http://morristhemoosetm.wixsite.com/rainbows