Really difficult to tell from the photos, but they look like aluminum extrusions.  Minton's cars were monel metal, a corrosion resistant steel, and pretty crude looking - at least the early ones.

I would think that if these were Cronkhite cars which had been used at the MSI, that  would have been mentioned in the listing, as it might increase interest and auction value. Is there a resource, for instance, that mentions the names of the cars used on the MSI layout, or that has better close-up photos of them? I have some of the MR articles from 1939-1940, but I don't recall particularly great photos of the rolling stock. I'll have to dig them out.

The obs is a Kasiner kit, I have 3 if you want one. And the coach I don’t know, Bob would know before I would maybe a Mac Shops?. Where is Carey when you need him? He knows for sure.

Were the cars on eBay now ever run on the M&SF?, maybe? I recall seeing the original passenger cars in the 1980’s as a child and they did not look like these at all. I added some shots from the 1941 MR for reference on the pre-war Budd Cars the M&SF used in 1941 pretty accurate I would say. In my humble opinion Minton would have custom built correct cars to reflect the actual Cars used on the ATSF, using generic kits was beneath him. Neither of these cars are remotely close to any Santa Fe lightweight passenger cars. Opinion.  

our version of the 1939 El Capitan with PRB rolling stock and Key Model E1’s (delivery detailing)

Hello all   Erik  thank you for posting the Pomona  and MSI images .....yes Obs is Kaisner ..very popular late 40's early 50's ... company is still in business now ..you can order a new one up .   see link  http://www.okengines.com/

Minton .. used the Pomona diesel and cars on the MSI and SF Treasure Island layouts...  one of the sets is on display at the Model Train museum in SanDiego , CA ...  link to museum   http://sdmrm.org/exhibitions/4592670233              see photos below from Minton pieces on display .  

Pomona made rather cutting edge stuff for 1939 ....today ..not so much ...but neat old vintage look ..I like it !   Lobaugh called the line in the 1941 catalog .

Bog question   who made ?   ...and where are they now ???  the MSI  engines and passenger cars of the 50's -70's ???...they were big time shiny ... like plated ?????...as a youth  they were just beautiful gliding around the layout ...

Cheers Carey 

above a Kaisner car 

odd car is the Pomona  39-41 ...much fewer ribs ..other cars Exacta   copper etched late 40's 

display at SanDiego Museum 

MSI layout 1955 ...those were  Central Locomotive Works engines? and who made the cars ????  where are they ???  this was after the 1953  modifications ...now O gauge ..hump yard added ..new control towers etc ... the kid is 68+ -   today 

Thanks for the link to the OK site. I did not know they were making O gauge passenger cars again

Great stuff Carey, love that 1941 Chief obs.. Coconino.. sweet 

Here we have a pair of monel metal Pomona Valley coaches - these went to either Allan Wehrle or Steve Neal.  Not my cup of tea, but historically interesting.