Dash-9s with DC motors under 'em allow ya 3/4" between DIAMETERS of wheels in the same truck. Beyond 3/4" ya gotta cut wheels ta no more'n 3/4" dia. diff.
Same rule applies ta -2EMDs.
But wheelsets on different trucks [6-axle ONLY] mustn't exceed 1-1/4" diameter. You cannot shim a wheel on a truck to compensate for this difference between trucks. Ya gotta cut 'em ta size.
The closer the wheels are ta one size, the better your overall performance will be. Wheels number two, and four, or five tend ta show more wear than others. At least from my experience...
I find myself truing number five on Dash-9s all the damn time! Older EMDs...varies.
But that rule...over 3/4" diff. within one truck, ya gotta shim the smaller wheel, or cut the largest down. This holds true ONLY on three axle trucks. Which is with SIX-axle units.
And ye can't go with a wheel that's over 1-1/4" larger than the largest one in the other truck.
Sharp eyes [and trackside detectors] find wheel defects for us. Our machine's an antique by most standards, but it works pretty damn well!
Flats spots can be machined out IF ya have enough meat ta work with. I've ended up with a scrap wheel a few times trying ta save one... So I always measure 'em all ta see if it'll be safe ta cut.
When I see a scrapper ahead of time, I let 'em know. Then we just change it out, for a close-sized wheel, instead of wasting machine 'machine time' tryin' ta save it.
Does that help Blackie? I hope so! I'm here ta help ya know...
-- Edited by Uke at 10:07, 2009-02-05
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One last point: AC motors are more critical in matching. EMDs, and GEs...only allow 1/8" difference between ANY two wheels on a three-axle truck.
Between trucks? I would think the same 1/8". That's quite small. It has to do mostly with wheel speed, and wheel slip modulation.
AC motors/wheels are allowed some teeny slippage ta keep 'em from overheating. But that amount is also tightly monitored, as is current output to every motor in the trucks under load.
I'm pretty certain my pal mntman could further the AC motor thing. But wheel diameters...1/8" difference between wheels.
ALL wheels on MACs, and GE-AC power!
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Hmm. That address doesnt look right. It looks like the link pointing here was faulty.
