As I understood it, the SD-7 was introduced to spread out the weight of the engine so it could run on lighter branchline rail. Except maybe on the DM&IR, I don't think the concept of a bigger and heavier engine with more pulling axles and greater tractive effort came along until the SD-24, which was several years behind the competing models, including the (IF-ME) TrainMaster, and the (Alco DL-600) Alligator. Conjecture only.
----- Original Message ----- From: "G. Elems" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Friday, October 20, 2006 12:46 AM Subject: {S-Scale List} More SD7 thoughts I like this discussion about modeling the SD7. I was curious as to the size difference the SD7 presented to the GP7. It turns out the SD7 isn't really that much longer and the overall engine is smaller than the PA-1 and FM Trainmaster. The "too big" argument doesn't hold up IMO. The SD7/9 had 13'5" wheel base with a 35' bolster pivot point and overall length of 60'8 ½". The GP7/9 had 9' wheel base, 31' bolster pivot point and overall length of 56' 2". Alco PA had 15'6" wheel base trucks, the bolster pivot points were 34' 2" and the engine was and overall 65' 8" long The FM Trainmaster had 13' wheel base trucks with a bolster pivot point of 41' 6" and overall length of 66'. All things equal, the overall length I used was the coupler face to coupler face. My numbers came from "Loco 1-The Diesel" which have drawings by Larry Jackman and George Trager. Seems to me that the SD7 would be a good engine to model. It was first offered in 1952 and they still ply the rails today. BNSF and NS still roster them. SP's ran till 1999 or so and many of theirs went to short lines and museums. Anyway just some thought about the SD7 and its relative position in size compared to some existing models. Greg Elems Reno NV [Non-text portions of this message have been removed] Yahoo! Groups Links Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/S-Scale/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/S-Scale/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
