Does anybody know the the differences are between a ‘phase 1’ and a ‘phase 2’ EMD SW7? Is there a ‘cutoff’ date when production shifted?
Jim
The only thing I can find that might be interpreted as “phase” production in the SW7 is that in the spring of 1950 EMD shifted from curved-top windows above the hood to rectangular windows. Other than that everything appears to have stayed the same.
I may need correction on this matter but I believe that the SW7 was merely an NW2 carrying around 1200hp. The two models may have slightly overlapped in production dates and one would really be hard pressed to distinguish one model form the other until the advent of the rectangular glass which was born only by the SW7. I have been giving heavy consideration to remodeling some of Kato’s new NW2s into SW7s by modifying these above-the-hood cab windows. In fact with some cosmetic altering of louvers and changing the above-the-hood glass this NW2 lends itself readily to kitbashing SW9s and SW1200s
The NW2 is easily distinguished from the SW7. True there was a difference in the cab glass but the NW2 has a shorter radiator. The radiator on the NW2 goes half way down where the SW7 takes the whole end of the hood. There was two variants in the NW2. The earlier version had a flat area on the top of the hood just in front of the cab. The later version had the slope from the hood right to the front of the cab without the flat area.
I did indeed overlook the fact that the NW2 had a half-height radiator grill. I’m not sure just when EMD eliminated the two step hood slope but it had to have been shortly after the Second World War and the single stage hood was on the majority of production. Assuming one had an NW2 with the single stage slope all you are going to have to do is (carefully) graft a full length radiator grill onto an NW2 to create an SW7 and that can be done with a second shell.
The ‘double step’ taper on the top of the hood went with late NW2 production(like the BLI HO model). The ‘1/2’ height radiator grill was standard all through NW2 production. I think that maybe most, if not all NW2’s had the ‘curved’ window glass.
The SW7 was the follow-on switcher to the NW2. It had the ‘full’ front grill and an internal 200 hp increase(1200 hp). BLI has 2 variations of the SW7 model, and I am trying to figure out what the difference is. Maybe the Ph1 has the older NW2 cab with the curved glass, and the Ph2 has the rectangular window glass?
Jim
Diesel Era ran a six part series on the SW7 beginning with the May/June '05 issue; as soon as I get to the storage box containing these issues I’ll see if Diesel Era identifies any phase/variations between early and late production samples besides the change from curved-top to rectangular windows.