The class for the Balwin 2 6 0 was an early class and I do not know if there were full scale drawings, there are in the 'construction' parts some drawings and these do run through the articles on it. I have not looked through all of it, but I have some drawings from it and they are 'parts of (the locomotive)' and not full ones. The later classes required drawings as there was both parts to buy, and a lot was to be made by the builders.
The drawing I have (of the cab) is nothing like the later 'Master Class' PDF drawings, and I do not think that that were any PDF draings made for the Baldwin mogul.
The entire project revolves around the parts that can be bought and what to do with them, en route to a model of the 2 6 0 in one of its many and varied styles. The prtices will have risen though!
However there are some drawings of the Nevada County Loco's available in the Narrow Gauge Annual, (by Finescale Railroader) books - available as back numbers from RailPub.
The 2007 and 2008 issues (which have in the lower right hand corner dates of Sept 2006 and Sept 2007: the spines show 2007 & 2008) have a mass of information/photos/ and drawings of the line including the 4 4 0 & 2 6 0 locos which include drawings of them.
I found it difficult to negociate the master class material in general. Too bad because I think there is some good material there. I did manage to get some material from the Porter section but some of the files gave me trouble in trying to down load.