heads up on Walthers trainline GP15-1 - Model Railroader Magazine

Trying to piece this one together... just so happens the Contemporary Diesel Spotter's Guide was my bedtime reading the other night. :)

OK, so, first of all -- there is only one model, GP15-1. (Actually there are two others, more on that in a sec.) What you're looking at is two different types of air filters. A GP15-1 with inertial air filters has the big blower duct with the "landscape"-oriented inlet above it. A GP15-1 without inertial filters has the smaller duct and multiple groups of vertical louvers cut into the body. 

According to TCDSG, only C&NW and SLSF (Frisco) ordered GP15-1s without inertial filters. Model name did not change with this option.

It looks like the Walthers GP15-1 was initially produced as a Proto 1000 model, which was offered with both air filter versions. Here's a Walters Flyer showing both:

(Though it refers to what TCDSG says are inertials as "Farr", and the other filter style as "Internal" -- as opposed to external??  Marre and Pinkepank have rarely failed me, so I'll stick with TCDSG's definitions.)

Based on what Walthers offers now, it looks as though when the GP15-1 was switched from Proto to Trainline, they only kept the small-duct, non-inertial (or, if you're Walthers, "internal") shell. That's all I see on Walthers' own site. Obviously, this is the wrong filter style for a Conrail GP15-1.

I looked on eBay and saw several ads for the Trainline loco using a photo of one with inertials. It looks like a stock photo so I'm guessing it was grabbed from Walthers' site of the old Proto model:

So, probably not a packing or picking error -- more like they used an old photo and you got the new loco.

Looks like you'll have to either find an older Proto 1000 model, or get one of the Athearns, or pretend Conrail bought some GP15-1s from CNW, Frisco or BN. :)

Aaron