SD70 MAC

 

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General:

The SD70 is a big and long locomotive. It uses the same 3 axle trucks as other USAT 3 axle truck diesels, with one axle pivoting. All axles are powered. Some earlier ones came with one axle per truck fitted with traction tires, newer releases have no traction tires.

Ted Doskaris weighed his at 10.56 pounds. Somewhat light for such a big locomotive.

 

Disassembly:

There are 10 large screws that hold the body to the chassis, but there are also 2 very small screws that hold the cab on. They are located at the rear of the cab underneath, at the very outside edges of the frame.

 

Modifying couplers for 8' diameter curves

Yes, it is possible! James Kuhns brought his by, and I've got some pictures here. More descriptive text will be added soon. Basically he modifies the coupler assembly and the pilot to allow greater swing, and removes the centering springs. You may have to use a car behind the loco with equally long coupler swing also. James has had success with the modern tank car, and an added benefit is it's weight due to the all metal construction.

 

The picture below shows the modification to the interior piece that also limits the coupler swing. The upper picture shows the modification needed.

 

The picture below shows the modifications to the pilot that allow the increased coupler swing:

The picture below shows the modification to the coupler. The centering springs must be removed, and the bosses to retain the spring must be removed.

 

Norm Baullinger found he still needed more "swing" with shorter cars, so he modified the coupler to put a swivel joint near the knuckle:

 

Disassembly:

There will be more here in the future.

Here are a few pictures of the main board in the loco, it's larger than most, maybe because of the ditch liights, or just because there is room:

Weather Underground PWS KCACARLS78