The builder's name, Harold Woods, Jr., appears in the first photo. A quick Google search led to this link featuring his 45' Standard Gauge Hellgate Bridge model--that's right, 45 feet of Standard gauge Hellgate bridge:
https://www.artprize.org/65041
The link also shows his O scale, 15' long scale model of the Illinois Central Bridge at Metropolis, Illinois.
Astonishing!!!!
Edit: Per Matt GN027's post below, Mr. Woods' middle name is "Virgil."