Sd50 vs sd40-2

[JanesCustomTrain]

I'm thinking Ben is right, while the proto uses the same frame, the model, there is more room inside the shell of the 45-2 so think they used a different frame.

Just from an economical point of view, what would be the advantages for a N scale manufacturer to produce a different drive for a model of a prototype which was produced and sold roughly 30 times less than the SD40-2 if they can use the drive they already have ? The models share the same drive.

Jane 

[Ike the BN Freak]

My under standing is that the SD40-2, SD45-2 and SD40T and SD45T-2 all should use the same frame.  So if that is the case, then makes sence that the SD45-2 uses the T-motor frame as the shell has more room to stuff frame into for weight.  Also I think someone here mentioned that the SD40-2W, uses the same frame, just milled down.

Plus the SD45-2 was released years before the SD40-2 was announced, much less delivered. Want to say the SD45-2 was announced/delivered close to 10 years ago

[JanesCustomTrain]

My under standing is that the SD40-2, SD45-2 and SD40T and SD45T-2 all should use the same frame.

SD38-2, SD40-2(W, F), SD45-2 length 68' 10"  bolster 43' 6"

SD40T-2, SD45T-2 length 70' 8"  bolster 45' 5"

The Tunnel Motors are not only longer than the SD38-2/40-2/45-2 they also have a bigger/wider truck space. The Tunnel Motors frames are not the same as the SD38-2/40-2/45-2 frames.

So if that is the case, then makes sence that the SD45-2 uses the T-motor frame as the shell has more room to stuff frame into for weight.

If that would be the case, the truck space on the SD45-2 would be way off and the trucks wouldn't fit between the pilots. Not the same frame.

Also I think someone here mentioned that the SD40-2W, uses the same frame, just milled down.

Same here, if that would be the case, the truck space would be way off and the trucks wouldn't fit between the pilots. These are not milled down Tunnel Motor frames !

Plus the SD45-2 was released years before the SD40-2 was announced, much less delivered. Want to say the SD45-2 was announced/delivered close to 10 years ago.

Not sure about the year but yes, that is correct, they came out first. But someone at IM must have had future projects in mind and thought that it would make sense, as the truck space of the SD38-2/40-2 (W, F) and the SD45-2 are the same, to design the frame shorter than necessary for the SD45-2 so they will also fit the SD38-2/40-2(w) !

I remember when I got my first IM SD45-2 and I took the shell off and saw the drive/frame for the first time, I was surprised about the size. Then I realized that it had roughly the same size as a Kato SD40-2 drive/frame and I thought clever, IM is ready for SD40-2s as well. 

Same with the new frame IM designed to allow the use of the ESU LokSound board, SD38-2/SD40-2(W) and SD45-2 (will) share the same drive/frame while the Tunnel Motors will have a different, new designed drive/frame to be compatible with the ESU LokSound board.

Jane

[u18b]

Well, now that I'm home, I'm not sure what I was thinking.

The IM SD45-2 chassis will work.  (though I hate the doughnut and slot interface that IM uses on that motor as I recall).

I need to order some shells from Atlas and then I'll have something to show.