Metra SD70MACH

[C855B]

I'm thinking twin prime movers are primarily for staged loading, similar to gensets. In commuter use you accelerate like heck out of the station and then back off once you get to track speed. I can guess that it's not a full shutdown after the accel part of the cycle, just enough idle to be ready for the next time.

I did a study in school of SP's San Francisco commute operations in the '70s. The FMs were monsters and nothing else could come anywhere close to 'em on accel. Explains why they lasted so long in the fleet.

[cjm413]

car body sd70 with 2 axle trucks?

My guess would be A-1-A like the BNSF AC44C4M's that were rebuilt from C44-9W's.

[cjm413]

The CADs I saw made it look like an SD70ACe, not a 70MAC

Progress Rail does have both ex-CSX SD70ACe's and ex-BNSF SD70MAC's.....

[packers#1]

With the built in redundancy of twin prime movers, higher HP output (5400 vs 4000), newer technology that's tier 4 compliant are the savings really bigger?

In terms of the parts inventory and lost run time due to maintenance issues both from training and mechanics being unfamiliar with the parts and systems of the locomotive, yes. Having a background in manufacturing and all the maintenance that goes into machines, having the ability to keep systems the same and parts inventories the same is going to make the bean counters in accounting extremely happy.

[Rio Grandeous]

Interesting that just between the Tiers of locomotives that they would equate to 6600 cars worth of savings in emissions!  That's pretty wild.