Is it a New Miracle of M.U. Run Numbers?

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Is it a New Miracle of M.U. Run Numbers?
Posted by K. P. Harrier on Tuesday, March 07, 2017 1:27 PM

Is it a New Miracle of M.U. Run Numbers?

Reports have been heard that instead of the traditional ALL units in a consist running at Run 8, a new better approach is that for the first unit to be in Run 8 while the rest in the consist are in Run 2.  Sounds kind of illogical to me, but have the railroad’s found a miracle method of efficiency?

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Posted by BaltACD on Tuesday, March 07, 2017 9:00 PM

K. P. Harrier

Is it a New Miracle of M.U. Run Numbers?

Reports have been heard that instead of the traditional ALL units in a consist running at Run 8, a new better approach is that for the first unit to be in Run 8 while the rest in the consist are in Run 2.  Sounds kind of illogical to me, but have the railroad’s found a miracle method of efficiency?

jeffhergert in one of the threads on locomotive operations mentioned a third option in the control of locomotives beyond GE's 'Trip Optimizer' and EMD's 'Leader' systems of locomotive control.  I forget the name of it - it is predicated on only having sufficient power on line and loading to operate the train at the company's desired speed.  In many areas (level or slightly descending) trains can be moved at track speed with the power of only a single engine in the locomotive consist.  When the train begins to ascend a gradient additional power will be placed back on line (at least that is the theory).

         

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Posted by jeffhergert on Tuesday, March 07, 2017 10:35 PM

It's called Smart Consist and IMO is total junk.  It can work with one or two trailing engines.  It is supposed to run the consist in the most fuel efficient manner to deliver the power requested, determined by the lead engine's throttle position.  Which in one case was going over Blair hill with the lead engine loading 120klbs while the trailing engine was in idle.

Somewhere in my work bag I have a booklet that describes how it works.  Where it puts the load and when.  They've tweaked it a bit, but it still isn't very good.  My MOP told me a while back it was going to go away, but hasn't yet.

Jeff 

RME
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Posted by RME on Wednesday, March 08, 2017 11:25 AM

If I remember Smart Consist correctly it's kind of like Harmon Select-A-Power, where the 'control' of the trailing units is just to knock some of them back to some minimal power rather than controlling them to appropriate run levels via translation of the MU signals on the governor wires, or some kind of high-level modulation of the engine/generator output power. Somewhere I recall reading that the choice of 'run' was determined to be the output power that would just balance the unit's HP at the railhead with the unit's contribution to train resistance.

I do SO hope that it's more involved than that, and has reasonably practical reliability long-term in service.

Combined with computerized slow-load and emission controls, it looks 'born to fail' to anyone who isn't a computer* or "automotive" engineer.  Or to anyone actually cognizant of what's involved in practical train-handling, I suppose.

 

*I'm not talking about real professional computer engineers -- just the kinds of folks who program zero-length trains into PTC and don't use Gray coding on rotary sensors.

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