Guy Wilber wrote

"Advertisements of any shipper, consignee or product, prohibited on all cars
except special cars of Mechanical Designation "L" and tank cars of Mechanical
Designation "T". In Interchange.

Note. -- The name of the "home point" of the car owner or lessee, a trade
mark or symbol, or the name of the owner or lessee, or any part thereof, will
not be considered advertising."

Thanks Guy, although excepting "trade marks" would seemingly cover a lot of
what is usually considering to be advertising. Like Tony's example of the
Chateau Martin cars (which were not T or L) bearing 40 foot slogans, e.g.

"For Good-ness Sake ... drink Chateau Martin Wines"

If that's just a declaration of ownership or a simple trade mark, then I
guess I don't understand the meaning of the word "advertising". I wonder if
you have any evidence of further relaxation of the 'ban' in the 1950's or
afterwards?

Tim O'Connor