In 1993, RTD commissioned an analysis of the historical resources along the southwest corridor, in anticipation of the new light rail. The results of this rather preliminary investigation indicated that four sites (Gates Factory, Denver Water, Coal and Lumberyard, and Overland Subway) needed further study by a team of architectural historians.

In all, a total of six sites were indicated as officially eligible for the national register, though further discussion of the sites or determination was not available in the abbreviate report attached below.