Model Railroading > Question Proto 2000 SD-7

Are these angines any good.  Seems like I remember axel gears breaking etc.  If any experience with these let me know.  Also if equipped with DCC to they run well/

IIRC Athearn replacement axle sets drop right in.  I have only had to change them on one or two Proto units.
They have a motor and light board that you can plug in an 8-pin decoder directly. 
I have other Proto units and they run fine.

The axle split problem was mostly with the 4 axle models, agree that Athearn axels drop right in. The SD7's seemed to have a number of frame designs and motors, I counted three combinations which made matching with other locomotives an issue. Eventually I was able to swap shells around to make things work. After quite a bit of tinkering and cleaning the set of SD9's have been running for many years. The P2K design at the time had a slightly different gear ratio, which also confused matching consists as well.

The plastic shells have awesome details and paint jobs, if you find one in your favorite scheme they are worth working with.

I only have experiance with the Proto SD9, very worthwhile locomotives. They had completely different gears from the various geeps that had the cracked gear issue. Did the SD7's ever have the same gears as the defective geeps? That would be news to me. Detail wise the SD7 and SD9 locomotives are virtually identical. The only differences I'm aware of is the the SD7 have the class light centered over the number board where the SD9 had them closer to the outside. And the SD7 has ladders on both sides of the nose where the SD9 only had a grab iron on the conductor's side, and that was only correct for just some SD9's.

Ted Curphey
Ontario, OR

I don't remember seeing a split axle gear on the P2K SD7's or SD9's.

The idea is the metal wheel has an half length axle that is inserted into the delrin gear ( I would think it's delrin but don't know for sure ) that has sockets on either side, something about the delrin part cause the socket to crack as the axle is inserted. For some reason Athearn uses a very similar design and the gear with sockets can be swapped.

The only dependable spotting difference between an SD7 and an SD9 appears to be the classification light placement above the numberboards, centered for SD7 and towards the outside for SD9's, there looks to be a cover not being detailed on the P2K SD7 model but the class light does change locations. Sometimes the frame or the design of the corner step well is cited but that seems to have varied for other reasons. Strapac has an excellent reference for SP SD7's and SD9's.

+ most hobby spotting features are for factory as delivered configuraton. Rebuilt equipment features would be in comparison to factory configuraton. But it's just a hobby.



Edited 2 time(s). Last edit at 01/20/20 22:05 by TCnR.

I've had a Proto SD7 for many years and I've never had a problem with the axle gears.

The corner steps on SD7s were also different compared to SD9s.  SD7 on left, SD9 on right.  Both were chop-nosed by the C&NW, and they also modified the access doors on the side sill of the 6606.  My photo taken at Eagle Grove, Iowa in June of 1974.

Dennis



Edited 3 time(s). Last edit at 01/20/20 19:31 by CNW.

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I contacted LifeLike about this issue more than a few years ago.  The problem was with the P1K four-axle units only.  Six-axle and P2K were not affected.

If the model starts to 'thump' (best way to describe it) the gear is split.

Athearn replacement gear part number is 60024.

That might have been the LifeLike line and it may have been true in N scale, but I have replaced many many thumping drive gears in P2K GP7, GP9, and GP20 units.  Not too many in the GP30.
I'm still pulling 20-year-old Geeps out of their boxes and finding them on units that haven't run a full yard in their life.
It does depress their price at swap mets.



Edited 1 time(s). Last edit at 01/22/20 17:56 by grahamline.