On Oct 11, 2020, at 22:09, Kenneth Montero <va661midlo@comcast.net> wrote:

From Piedmont & Western Railroad Club website - Railroad reporting marks:

First class source, that.

CGW = Chicago Great Western
LPT =?

<sarcasm>Lone Pine & Tonopah (AKA Little Potties & Toilets), Kermit Paul's layout in Walnut Creek, CA</sarcasm>

MRJX = Marcus-Ruth-Jerome?. Possibly a Mather refrigerator car (type R). The company rendered fat.

Thankyew; I'd seen that in a photo somewhere...

CMstP = Chicago, Milwaukee & St. Paul - a prior name for Chicago, Milwaukee, St. Paul & Pacific (Milwaukee Road)
TIDX = TIDEWATER OIL CO.; TIDE WATER ASSOCIATED OIL CO.; TIDAL REFINING CO.; TIDAL GASOLINE CO.]
GF = Georgia & Florida Railway
MLT = ML&T = Margan's Louisiana & Texas Railroad

see above in re: MRJX.

P&P = P&PU = Peoria & Pekin Union?
KTOX (and tank car) -unknown

s. be DTOX, neh?
It all helps fill in the gaps.