cs641 Wrote:
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> Guess I never realized the SD9 is a 6
> axle unit, also didn't realize the line was strong
> enough to host a 6 axle as the current units are 4
> axles.
The original purpose of 6-axle diesels was to reduce the axle loading, or in the case of higher horsepower narrow gauge locos to also provide enough traction motors to use the available power.
An SD9 typically can weigh 165 to 180 tons. I believe a typical GP9 weighed closer to 120-125 tons. A typical 6-axle unit now weighs 200+ tons.