GE "XR Series" Upgrades?

I came across the following photo on RailPictures:

http://www.railpictures.net/viewphoto.php?id=274701

The caption mentions that these units had the words "XR Series" on the frame, and that XR apparently stood for Extra Reliability and that this was some sort of upgrade performed on the units by GE.

I've never heard of XR Series until now. Can anyone tell me anything about it?

I believe it was basically the precussor to the -7 technology. It was installed in late production U series engines. Heres a promotional paint schemed L&N unit U30C for the XR tech. http://www.lnrr.org/images/Diesel%20Loc ... MLeach.jpg

"XR series" was announced in 1972, I think September. EMD had introduced its Dash-2 series at the beginning of 1972, and I think a lot of people saw this announcement as an effort at a "tit for tat" on GE's part. I think the actual technical upgrade was a bunch of internal features, many of which were already available as options: the one that sticks in my mind is steel-crowned pistons, already standard on U36 (and U34CH) and available (as an option??) on other models. I ***think*** (but am not sure of my grounds) that U23B-XR all had AC generators: in which case, since GE built some DC U23B after this time, not all post-1972 U-boats were "XR-series". I think the announcement covered U18B, U23B, (no U23C were built for North America after this) U30B and U30C, U36B and U36C. So it may be that U33C built after this for SP were non-XR, and that the U33C was kept in the catalogue as a low-price option for railroads unwilling to spend the money on the XR package. (Please note the "I think"s and "it may be" in the last few sentences: I'm working with conclusions drawn from press and railfan sources, remembered from a quarter century ago!)

I do not know of any external spotting feature distinguishing XR series from ordinary U-boats. GE may have offered a sight-glass on the side of the long hood (for checking engine water without opening doors) like that on EMD's Dash-2 series, but I don't hink many units got it.

As for paint jobs-- One L&N U30C and one Frisco U30B got special paint schemes to publicize the XR line, and I've seen other pictures showing the lettering on the frames of Rock Island U30C, but I don't know of other units so decorated. It might be worth looking at photos of late U30B and U30C from these and other railroads to see if any are labeled as XR series.

From what i've read there are no external differences.

ATSF SP--
My suspicion is that that's riht, or at least no CONSISTENT spotting features. After posting, for curiosity I tried googling for more information: there were a couple of model railroad sites that implied some spotting features (louvers on the door of some equipment box, round-topped headlight casing), but I suspect these are just features of later U-series, and not specifically of XR. As for the "ER Series" stencil next to the builder's plate on the frame at left front, as seen on the Rock Island U30C, I found a site that said that BN's 5380-series U30C (problably lots of others, but these were units specifically mentioned) were XR-series, and did NOT find any photos showing this stencilled on them. (The Rock Island's U30C were built in 1973, I think, when the XR series was still new: it may be that after that GE figured they'd milked the announcement for all it was worth, PR-wise, and stopped emphasizing it. Which wouyld make sense if, as I think was the case, the "XR series" was just a publicized stage in GE's continuous process of improvement.)

Possibly some one else here could answer this. Didn't the XR series ultimately end up as part of the B and C series (examples B30-7,C30-7and C36-7) of locomotives from General Electric.

The "Dash-7" series (as it is now called: I think at the time they were called something like "the new series"), C30-7 starting production in second half of 1976, B23-7 about the middle of 1977, was the NEXT generally announced GE product upgrade after the XR series of 1972. GE's modifications and improvements of its locomotives are continuous, so early Dash-7 units had a lot in common with XR series, but there were some changes made on the Dash-7 designs which were not included as part of the XR series, including some externally visible ones. Notably: U30B-XR and U30C-XR did not have "wingspan" radiators, B30-7 and C30-7 did; equipment blower on U23B-XR and U30B-XR is in front of the engine, that on B23-7 and B30-7 (other than B30-7A1) is at rear, so there is no vent on the hood side behind the cab; etail changes to nose sheet-metal,....

One (maybe) difference: GE stopped building U-series after the Dash-7 series was introduced (even rebuilding an old U30C when they got a one-unit order for a U34CH rather than building a new U-boat), but I think that not all U-series locomotives built in late 1972 to end of production had the XR-series features: but I could be wrong about this.