Anyone know of any Class 1's implementing this promising sounding technology for their EMD based road switcher fleets?
http://www.nre.com/news/bnsf-tests-nre%E2%80%99s-heavy-haul-independent-axle-control-iac
CSX was to initially increase the tractive effort of their SD40-2's going through the Dash 3 program from 82,000 to 130,000 pounds, presumably through use of similar technology. But they seem to have backtracked with SD40-3's instead listed at the older figure.
Bet this would've been perfect for Montana Rail Link a few years ago, although it's a moot point now.
Likely to be of somewhat limited use for many Class 1s, as the expense of maintaining DC traction motors, the necessary derating of the motor at slow rotational speeds, and the high-speed propensity to birdsnest are all still present.
Having said that, but also having observed creep control in action in the mid-90s, it is easily possible to modulate traction power to a set of DC motors in ways that give highest possible torque with limited overspeed even in severe slip conditions. I'd be very interested in seeing the full technical specs on how this is implemented, but I suspect much of the interesting equipment and its programming are proprietary.
Yes, this is a potential big thing for smaller Class Is and Class IIs, especially if its cost can be used to tie into better emissions performance. I expect the 'real' benefit here is the decreased risk and increased profitability that make financing the conversion less difficult and costly to arrange. A secondary benefit might be decreased insurance costs.
OvermodHaving said that, but also having observed creep control in action in the mid-90s, it is easily possible to modulate traction power to a set of DC motors in ways that give highest possible torque with limited overspeed even in severe slip conditions. I'd be very interested in seeing the full technical specs on how this is implemented, but I suspect much of the interesting equipment and its programming are proprietary.
A surprising amount of info is in the locomotive service manuals. At the 50,000 ft level, both EMD and GE just try to maximize current out of the traction alternator.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Don might remember that the old SD24s had a crude wheel creep system. No computers, no wheel speed monitoring. Just a whole bunch of relays (including a WCR wheel creep relay) . These were the beginning of high adhesion EMD locomotives and they sorta worked...
That said , back i the 90s there were dozens of after market builders that sold micro processor comtrolled adhesion packages. They worked very well . I don't think a lot has changed for the DC locomotives. NRE now markets the "N Force" system that looks great. Most systems depend of either axle speed probes or strictly current transducers, in any case both systems initiate wheel creep and control it based on absolute wheel acceleration.
Randy
Leo_AmesCSX was to initially increase the tractive effort of their SD40-2's going through the Dash 3 program from 82,000 to 130,000 pounds
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