Western Railroad Discussion > GE leading UP's Ft. Collins local

Yesterday I ran across Union Pacific's Ft. Collins local North of the BNSF diamond on the branch up to the cement plant at Boettcher with UP 7060 leading, a convertible GE model AC4460CW while waiting for maintenance-in-the-way working ahead.

Snapped with my phone on my lunch break:}

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Literally, good catch.
JB

Nice angle and OK I'll bite, and ask, because I really don't know and have wondered since I saw the term Convertible ----can the hoghead make this change running out on the road or is it something for the shop forces?
Brian Stevens

Great shot. Love the angle also.

Ronda Thomas

SCKP187 Wrote:

> Nice angle and OK I'll bite, and ask, because I
> really don't know and have wondered since I saw
> the term Convertible ----can the hoghead make
> this change running out on the road or is it
> something for the shop forces?

Short answer: The conversion would have involved swapping out a 4400hp prime mover for a 6000hp prime mover, so it would have been a job for the backshop.

Long answer: In the mid-1990's, GE and EMD were both rushing to develop 6000hp locomotives for UP (the AC6000CW and SD90MAC-H). This required developing and debugging new prime movers. GE turned to Deutz to develop their HDL engine, while EMD took a leap into the world of 4-strokes-per-cycle with their new 265H. While both builders were working out the kinks in their new engines, they began supplying railroads interested in 6000hp locomotives with "convertibles;" 4300-4400hp locomotives fitted with the tried-and-true GE FDL and EMD 710 prime movers, but with the carbody, radiators, electrical cabinet, etc. necessary for the 6000hp prime movers. The plan was that once the new prime movers were ready, the convertibles would be retrofitted and "converted" to 6000hp machines. UP called the GE convertibles "C6044AC" and took 106 of them; they dubbed the EMD units "SD9043MAC" and took 309. CP Rail and CIT leasing (CEFX) also picked up convertible SD90MAC's.

GE and EMD did eventually deliver several orders of genuine 6000hp locomotives fitted with the new prime movers, but initial reliability was poor. After considerable tinkering and a lawsuit with Deutz, GE eventually got the AC6000CW's to behave reasonably well. EMD tried a number of retrofits on the SD90MAC-H's, which reportedly suffered from electrical system and ride quality issues along with engine troubles. In the end, railroads including UP and CSX (the other customer for the AC6000CW) went back to buying standard 4300-4400hp locomotives. None of the "convertibles" were ever retrofitted with the 6000hp engines, and in fact a few years ago UP did just the opposite, "de-converting" their AC6000CW's with 4400hp FDL's. The 6000hp SD90MAC-H's were either turned back to EMD or scrapped. UP continues to use its GE "convertibles," and the EMD ones are slowly coming back into service after being stored while a frame cracking issue was addressed. CP Rail also had their SD90MAC's stored; not sure what their current status is.