Pop's Bridge: Bunting, Eve, Payne, C.F.: 9780152047733 ...
https://www.amazon.com/Pops-Bridge-Eve-Bunting/dp/0152047735
Pop is a high-iron worker, what folks called a "skywalker." And, in the year 1937, he is one of more than a thousand men who are engaged in constructing the "impossible bridge." Robert's friend Charlie Shu's father, a painter, is also involved, but Robert secretly feels Pop's job is more important than Mr. Shu's.