FP10's

I'm aware that the FP10's were rebuilt GM&O F3's and F7's, for the MBTA. Were these engines repowered with new prime movers or did they all retain their original prime movers?

Those old F units would have had at least the 567BC upgrade to their engines. This thread on rypn states the rebuilt F units got 567Cs, which is possible. http://www.rypn.org/forums/viewtopic.php?t=39820 I'll take a look at some old info from the late 1970s and report back. By the way there were 18 F3As and only one F7A used in the rebuilds.

Ed in Kentucky

News item in Extra 2200 South Issue 63 states that the "F3au's" for MBTA were to be rebuilt using the
innards of 12 ex-PC GP9's, starting with 7533, 7535 and 7559 at Paducah in May 1978. Five additional
GP9's were to be rebuilt in kind for MBTA.

Factoid. 16-567 engines in F and GP units aren't the same: different power take-offs for traction motor blowers, I think. The BL-2 used the style from F-units: when a preservation society tried to restore a BL-2 to working order some years back, they ended up taking an engine from an F-unit to simplify the task. Obviously, if there were 18 F3a and 1 F7a used for the "FP-10" project, F9 donors would have been in short supply, and commuter agencies are better funded than preservation societies, so they used GP-9 engines and paid for the extra work involved in modifying the engines!
---
Rebuild of 567C engines in the 1970s often replaced the cylinder+piston assemblies with 645 "power assemblies," typically allowing a higher power output. So, curiosity question: were the FP-10's rated at 1750hp (as one would expect if they got "pure" 567C engines) or a bit more (as would have been possible with 645 power assemblies installed on the 567C frame)?

That was going to be my next question, what were they rate at for horsepower? I've looked a little bit for some answers but haven't found any solid information, only a couple of YouTube videos that referenced them has having 1500hp.

I thought I remembered the rebuilt "Paducah Geeps" having an increase of about 100 hp over the original
build. Going back to Extra 2200 South, a summary of recent rebuilds in Issue 58 ( Oct-Nov-Dec 1976 ) noted
"GP8" was a 1600 hp GP7u and "GP10" was a 1850 hp GP9u. If ICG made the same mods to the MBTA units
that they were making to their own rebuilds then the FP10's were likely rated at 1850 hp but so far I haven't
found anything that actually says that.

The May 1979 issue of Railfan & Railroad Magazine on pages 18-19 has a news item and photo detailing
MBTA 1100 beginning revenue service in Boston on 25 Jan 1979 and states the the unit is rated at 1850 hp.

If I remember correctly what I read back in the ... 1970s? ... ICG was able to get their 100hp power increase on their rebuilt Geeps without using 645 power assemblies. (Their "GP-8" and "GP-10" rebuilds typically had four exhaust stacks: this was part of a "liberated exhaust" system that got more power by reducing the back pressure of the engine exhaust. Missouri Pacific was also a fan of this idea, and rated its GP-18 units at 2000 hp.) With 645 power assemblies, the engine would be close to being equivalent to the 16-645 engine used on (2000 hp) GP-38: I thinkMilwaukee had SD-9 units upgraded in this way to2000 hp.
So... I'm happy to believe that the "FP-10" was an 1850 hp unit... but don't have any confident opinion as to how this rating was achieved.

I was searching the subject with Google and one message board discussion I read led me to look at my
copy of "The Diesel Spotters Update" (Pinkepank, Marre, Kalmbch Books 1979 ) in which there is a chapter
on Railroad shops capital rebuild programs- pages 106 to 125 devoted to EMD roadswitchers rebuilt by MILW,
ICG, SP, BN, ATSF, CNW and CR. A common theme is the liberated exhaust system and a central air system,
apparently initiated by MP and omitted from the tally because MP rebuilt it's units on a one-by-one basis as
part of routine maintenance and not part of a program and each unit was a little different from the others.
MILW and BN should be excluded from this group because they installed 645E engines. The only other mention
of 645 parts was that ATSF experimented with 645 parts on CF7 2542 but wasn't convinced to expand the mod
to the rest of the program; the ATSF, SP, CNW and CR retained the original hp ratings. ICG rebuilt 123 GP8's
and 343 GP10's with the frames and blocks being freely interchanged in the process including a 567D block
from a wrecked GTW GP18 and briefly experimented with a 2000 hp rating but converted all back to the
lower ratings after Feb 1969. Interesting subject- there has probably been a more involved article written on
it somewhere and I seem to remember one on VMV somewhere....

The late J David Ingles wrote an article titled "Rebuild or Replace? The Paducah Answer" His article was the 28th Annual Motive Power Survey and was on pages 40-49 of the September 1976 issue of Trains magazine. The article noted that the 567 engine equipped locomotives rebuilt at Paducah would have the fuel rack and governor adjusted, new pistons installed, new chrome cylinder liners and new crankshafts installed. These new parts and the four stack exhaust pioneered by Missouri Pacific would give a 100 horsepower increase to the rebuilt engine.

Ed in Kentucky