Norm,
Search youtube for Powder River Basin Coal Trains if you haven't already. You can see hoppers along with locomotives used. Mick's link gives allot info. This website also has allot of info as far as photos.
http://www.railpictures.net/album/807/
Dean
Um, I studied all consists in photos dated 1992-2002 and the hoppers are mixed owners on some consists and not mixed (unit) on others. The same with hopper types, mixed on some consists but not mixed on most.
As for locomotives
EMD SD9043MAC (2000) UP/SP/UP-rev/end?
EMD SD70MAC (1999) BNSFp/BNSFe-rev/BNSFe-rev/end?
EMD SD70MAC (2002) BNSFe/BNSFe/end unk
EMD SD70MAC (1999) BNSFp/BNSFp-rev/end?
GE C40-8 (1995) C&NWyb/UP-rev/C&NWyb/end unk
GE C40-8 (1995) C&NWyb/UP-rev/UP-rev/end?
EMD SD70MAC (1998) BSNFe/BNSFe/BNSFe/end?
EMD SD70MAC (1998) BSNFe/BNSFe/BNSFp-rev/end?
EMD SD60M (1993) BNSFg/BNSFg-rev/SFby/BNSFg-rev/end?
GE C30-7 (1994) BNSFg/BNSFg/BNSFg/BNSFg-rev/end?
EMD SD70MAC (1998) BNSFp/BNSFe/end?
EMD SD60 (1997) GMem/BNSFg-rev/GMem-rev/GMem-rev/end?
GE AC4400CW (2000) UP/UP-rev/end?
EMD SD70MAC (1997) BNSFe/BNSFe-rev/BNSFe-rev/end?
GE C30-7 (1998) BNSFg/BNSFg/GMem-rev/GMem-rev/end?
Edit: Bold are locomotive consists that I have in trainz
All UP locomotives were striped but not lightening and without flags or other logos.
Livery abbreviations e=executive, g=green&white, p=pumpkin, em=Electro-Motive blue&white, yb=yellow&black, by=black&yellow
Other abbreviations rev=locomotive reversed, /end?=unable to determine if an end helper was present, /end unk=end helper(s) present but unidentifiable.
It seems that the conclusion I drew from the 1996 video that at some time between 1997 and 2000 the standard practice changed from three locomotives at the headend to two locomotives is borne out by these pictures.
Out of the nine pages/129 pictures only two were non-coal trains and are not included.