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Can P42s go faster than 110mph?

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Can P42s go faster than 110mph?
Posted by zkr123 on Saturday, August 9, 2014 2:13 PM
I have heard a rumor that the P42DC can go faster than 110mph. I heard they can achieve 120mph, is this true?
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Posted by timz on Monday, August 11, 2014 12:24 PM

In other words, if you disconnect whatever overspeed protection it has and accelerate to 120 mph downhill, will it fly to pieces? Suspect not, but none of us has much idea how much faster it could go without damage.

Nor do we know how fast it could go with higher gearing.

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Posted by MidlandMike on Tuesday, August 12, 2014 7:51 PM

I understand the 110 mph limit has more to do with the un-sprung weight of the nose-hung traction motor.

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Posted by oltmannd on Wednesday, August 13, 2014 8:36 AM

Big difference between "can" and "should".  

Would the traction motors hold together at 120 mph w/o changing the gearing?  Maybe.  For a short while.  

Would you like what a nose-suspended traction motor does to the track at 120 mph.  No - but it probably wouldn't derail (particularly if you had fresh 1:40 taper wheels on it)

It maybe possible, but it's a bad idea.  110 mph for a P42 isn't the best idea...

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by Paul Milenkovic on Friday, August 15, 2014 2:47 PM

The VIA Rail Canada's LRC consisted of LRC coaches, which are somewhat but not completely unlike Acela coaches, and the LRC locomotive, a low profile locomotive that matched the low roof profile on the LRC coaches but was really an MLW (Montreal Locomotive Works) version of an ALCo. 

The LRCs were rated at 125 MPH capable and tested up140 MPH.  What kind of traction motor suspension, not known.  They were limited to 100 MPH in service.

The LRC locomotives have been replaced by Genesis (P42) Diesels when the wore out -- coaches last longer than locomotives it seems.  It seems that the current VIA LRC trains with Genesis power are limited to 100 MPH.

If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?

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Posted by CSSHEGEWISCH on Saturday, August 16, 2014 6:45 AM

Speed limits are as much a factor of what the track structure will tolerate as the mechanical limitations of the locomotive and rolling stock.

The daily commute is part of everyday life but I get two rides a day out of it. Paul
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Posted by Overmod on Saturday, August 16, 2014 12:00 PM

Paul Milenkovic
The LRCs were rated at 125 MPH capable and tested up140 MPH.  What kind of traction motor suspension, not known.

I believe the LRC locomotives used four GE 785PA-2 traction motors.

Some of the LRC locomotives were geared for 125mph, some 103 -- I don't remember the specific gear ratios involved. Note that both acceleration and starting TE were significantly affected by the higher gear ratio.

I believe the trucks on the Genesis units are designed for higher speed than 110mph, so the physical limiting factor (other than governing) would be TM gear ratio.  Loss of acceleration and TE would be a problem for Genesis units that were given higher-speed gearing, and I suspect it would be difficult if not impossible to run them effectively in MU with 'standard' units.

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