The picture is also on the Find a Grave web page for Walter Johnson. There is no mention of a Carol or Barbara as his children. However, if you look under Walter's mother, Minnie's page, a 1940 census lists:
* 1940 Census - Montgomery Co., Maryland
-Head, Walter Johnson, 53, Ks
-Mother, Minnie Johnson, 73, In
-Son, Walter Johnson, 24, DC
-Son, Edwin Johnson, 22, DC
-Son, Robert Johnson, 19, Ks
-Daughter, Carolyn Johnson, 17, Nv
-Daughter, Barbara Johnson, 14, DC
-Brother-in-law, John Burke, 52, Ks
-Nephew, John G Burke, 20, Ks
-Nephew, James Burke, 16, Ks
Both links:
https://www.findagrave.com/memorial/2453/walter-johnson
https://www.findagrave.com/memorial/...-olive-johnson
Also, a link to Carolyn selling her home in 2017:
https://www.washingtonpost.com/news/...ling-her-home/