Purchased second hand
Hobart Estate Lumber Operated E&P Eureka
Colusa and Lake Operated SPC 3
Lake Tahoe Railway & Transporation Co Operated SPC 6
Carson & Colorado
Notes on other Baldwing 4-4-0's (eliminating possible locos)
SPC No 1 was a 8-14-C
Carson & Colorado 4-4-0's were 8-22-C
Sources
Manuscript
Baldwin Locomotive Class lists for 8-18c and 8-18.5c from CSRM, Microfilm
Baldwin Specification sheets for specific locomotives from CSRM, Microfilm
Baldwin Locomotive "Engine Drawings"
From Stanford Univesity, "M15", mirofilm
Books
Dickinson, Narrow Gauge to the Redwoods
Fabling, Steinbech County Narrow Gauge
Ferrell, Southern Pacific Narrow Gauge
Hammand, California Central Coast Railways
Myric, Railroads of Nevada & Eastern California, Vol 2.
Westcott & Johnson, The Pacific Coast Railway
Other
Tom Armstrong's NCO locomotive roster from 
http://www.urbaneagle.com/nco/nco-loco-roster.html