You might be interested to know that Athearn has run upgraded versions of the MDC Thrall gons. The upgrades have improved the body substantially; one MAJOR fix to the old MDC cars is the bottom ribs did not match the side ribs and were offset. The only way to correct that on the kit would be to cut the bottem pieces apart and glue them on so they match better. The RTR cars fixed that and have nicer grab irons and ladders as well. Occasionally the old sets show up on Ebay but Athearn has a new run of 10 numbers due out this summer:
http://www.athearn.com/Search/Default.aspx?SearchTerm=BN+Thrall&OA=True
Rio Grande. The Action Road - Focus 1977-1983
The 7/8" BN logo scales out to about 79.5" in HO (an HO scale inch is equivalent to about .011"), so the 80" one on the decal sheet sounds to me to be the proper one. I'd guess the larger one to be meant for boxcars or hoppers, perhaps.
Wayne
Got a question for my BN friends in the forums: I am modeling some of the 570015-57249 Thrall Gondolas. I have five that are the BN-lettered Roundhouse Thralls. Using both the 87-251 and the 87-1377 Microscale sheets, the lettering on the left side was replaced (the top lettering and the reporting marks) and the dimensional data was changed to be accurate to the number series. The exisiting BN logo was left alone.
Now for the problem: I recently purchased another 5 of those same type of Thrall cars. They are lettered for a different roadname. I will again use the same mentioned Microscale sheets. However, with these cars, I will need to use a logo. By measuring the logo on one of the BN cars, it comes to 7/8" tall. The 251 sheet has two different sizes of logos (80 inches and 87 inches). The 7/8" measurement falls between the two logos. I am unsure as to which size is correct. I am leaning toward using the 80 inch ones. However, any advice my forum friends can provide would be welcomed.