GP-9 1514: history?

I saw GP-9 1514 (chopnose; painted in the current dark red with the gold "medallion" on the side long enough ago to be fairly dirty now) in the yard at Edmonton, Alberta (not far from the yard office, a few blocks south of Whyte Avenue) today. It has unusual sheet-metal work at the rear end. About the top third of the end of the long hood (so: the part with the numberboards and lights) is of normal GP-9-ish shape but a bit below the lights it is build out several inches beyond the normal end-point, and squared off so the rear of the lower part of the long hood is a flat surface from side to side.

It was coupled to a pair of dump cars (there appears to be ballasting going on), so I thought this might house special equipment for operating the dump cars, but when I asked a group of railroaders having lunch at the yard office none knew of any special equipment: one got up to look out the window to see what I was talking about, and apparently had never thought there was anything unusual about the unit.

I have seen similar built-out hood sections in photos of first generation geeps bought for service on suburban trains: it housed extra power take-offs to allow the locomotive to provide electric current for train lighting. Did CP have GP-9 so equipped? and did the 1514 start life as one of them?

Apparently I was lucky: it IS a GP-9. (The spotting feature I rely on is the number of vents on the battery box, and CP has some upgraded GP-7 on which the original batterry box covers have been replaced with GP-9 style...)

As for the appearance, it is kinda like this
http://www.rr-fallenflags.org/bm/bm1555aga.jpg
but not quite: the squared-off portion is, I think, higher on CP 1514, and the vent on the side is different. If you have Kalmbach Publishing's "Diesel Locomotives: the first 50 years," there is a photo there of the end of the long hood on CNW 1714, which I think matches CP 1514 exactly-- the photos of such CNW GP-9 at rr-fallenflags, however, are taken from angles that don't show the long hood end. ... According to the picture caption in "Diesel Locomotives: the first 50 years," CNW, B&M and CNJ had
GP-7/GP-9 with this sort of feature; there are photos of CNJ GP-7 ("GP-7P") with it at rr-fallenflags, and they look like the B&M unit rather than like the CNW or CP examples.

I believe it's a larger sand tank on the long hood end.

CP 1514 started off as a regular freight GP9, #8627, built by GMD in 1956. It was one of the first units to be rebuilt with a chopped hood and other upgrades, and as such it features the expanded sand boxes that CP added to the first GP9 rebuilds. A few other units in the low 1500 and 8200 series had similar additions. My understanding is that the added sand capacity was not worth the cost of upgrading, so the majority of the GP9 rebuilds retained the original long hood end.

Tyler, Michael--
Thank you! I'm astounded: the rear end treatment looks SO similar to that on the GP-9 illustrated in "Diesel locomotives: the first 50 years".
When i saw it, it was parked with the front facing away from me: I could see that it had a chopped nose, but didn't notice whether it had any built-out sections for added front-end sand capacity. ... I pass the CP yard fairly regularly, and will look out for this unit to see if I can see any other details.

To clerify, the CNW, CNJ, and BM units had the lengthened hoods for train lighting generators. They were used in commuter service, where the axle generators did not run far or fast enough to keep the lighting batteries charged.