A copyriight renewal search was done for any renewals by Pullman for the years 1968 and 1969. No information was discovered; there is no evidence Pullman renewed its copyright on this ad.
The ad is not covered by any copyrights for the magazine it appeared in.
"A notice for the collective work will not serve as the notice for advertisements inserted on behalf of persons other than the copyright owner of the collective work. These advertisements should each bear a separate notice in the name of the copyright owner of the advertisement."
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.
{{Information |Description=Ad for the then new Rock Island Choctaw Rocket streamliner built by Pullman-Standard. |Source=[http://www.ebay.com/itm/1941-Ad-Pullman-Standard-Car-Manufacturing-Choctaw-Rocket-Silver-Ink-Train-/110939246710?forcev4exp=true#h...