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Post by arsenix2001 on Mar 25, 2024 13:17:57 GMT -5
I've noticed this on a couple of my sd70ace units and in particular a BNSF ES 44 from the original production run. They seem to run noticeably faster in one direction versus the other. Checked for binding in the trucks and lubricated everything. I didn't want to go as far as splitting the case. Ive had it running in both directions for an hour or so and it has helped quite a bit. Speed is "Almost" matched now. The only thing I can think of is usually I ran this unit in reverse in a 3 loco consist and that is possibly broke in only in that direction? Should I tear down further or just keep exercising? Main reason any of this came up is that the new ES 44 arrive today and is quite a bit smoother and quicker. I noticed the same thing with the new one of the SD70 as well.
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Post by ptitrainrouge on Mar 25, 2024 14:13:50 GMT -5
I have the same thing on several locomotives
speed is higher in reverse than normal run (even in DCC)
I have no clue of what is involved
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Post by ednadolski on Mar 25, 2024 14:20:32 GMT -5
This isn't too uncommon. Some DCC decoders will allow you to compensate by biasing the speed in one direction over the other.
Ed
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Post by BAZman on Mar 26, 2024 13:34:12 GMT -5
Sometimes it’s because the trucks center is between two axles and not directly over the middle axle (for a 3 axle truck). But for a 2 axle it may just be the worm gear drive the gear engagement angle being a push rather than a pull.
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Post by rgs455 on Mar 26, 2024 14:07:39 GMT -5
I have this with my GP30 and GP9... Eventually I cut down the CV5&6 on the faster egine to make them run smoother.
The GP9 has run more, so it's possible that the GP30 just needs some mire break in time.
On the SD45's it's much less present and the new SD40's run at the same speed right out of the box...
BR Boris
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einot
Engineer
Posts: 102
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Post by einot on Mar 28, 2024 1:04:57 GMT -5
Sometimes it’s because the trucks center is between two axles and not directly over the middle axle (for a 3 axle truck). But for a 2 axle it may just be the worm gear drive the gear engagement angle being a push rather than a pull. I’m not sure if I understood correctly so here’s an honest question: Wouldn’t the push/pull case always be present on the other truck and change along with direction? Or is my thinking wrong? BR, Eino |
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