Hi reving EMD engines

[tate955]

Hi,

Has anyone any info on EMD 645 and 710 engines that were built to rev at above 900,930 RPM. I understand that some were put into loco's. Can anybody tell me which ones?

I also understand that EMD engines reliability suffers at these higher speeds, is this true?

any info would be much appreciated

Thanks

Tate

[nickleinonen]

i don't know of any applications where they turn over 950rpm, but i have had a 16-645f3b turning 1200rpm or so when setting the mechanical overspeed trip... someone had messed around with it and it was way out...

[tate955]

Thanks.

I'm sure I heard somewhere of a 1000rpm 2 cycle EMD, could be wrong though.

Do you or anybody else out there have any knowledge on how reliable EMD egines are at 950RPM compared to the standard 900?

Was the F3b A 950 and if so what loco(s) Have them fitted?

[nickleinonen]

the f3b was in one of our sd50's.. i think they are governed at around 900rpm... our sd75's turn the 950rpm and they seem to be about as reliable as the sd70's and sd60's that turn ±900rpm... all of them blow up pretty regularly

[tate955]

LOL!

Seems that the Sd50 has a poor reputation for reliability with the last of the 645's.

Is this your experience? If so, what goes wrong?

Tate

[DutchRailnut]

In Tug boat use I have seen 710's run as high as 1045 RPM continous.
but not in locomotive use.

[junction tower]

According to a recent Trains magazine article, Jack Whelihan, former EMD technical guru, said that the increase from 900 to 950 rpm created unanticipated harmonics and vibrations that literally shook the the units apart early on. There was also some poorly designed pieces by some younger less experienced engineers than those that created the 40 series. They also found that the wiring technology that EMD had used from the begining was suddenly found to be no longer adequate for the job and was breaking down in severe service aplications. Wheelihan stated that SD50's upgraded with second generation parts and serviced by technicians that understood it's somewhat complicated wheel slip system, they should provide excellent service.

[mxdata]

1000 RPM is a standard operating speed for EMD engines in 50 Hz power generating applications, but this is a railroad forum so we aren't supposed to discuss that here.