You might want to check out the buildings by Dave Drake (dmdrake). He made a series of city buildings and factory buildings that would fit into this period.
Dave Drake (dmdrake), John Keenan (jkeenan), and a few others have made some nice buildings that would match this period. They were made for TRS2004, but they work fine in TRS2006.
Dave Drake's Cityscape series contains whole neighborhoods without roads so you can put in what you want as well as complete industrial areas with old-fashioned factories.
I used a bunch of his 2D-buildings from his Cityscape series for my industrial areas on my layout. My layout was based on the New England areas with plenty of old textile mills and warehouses like those found in Manchester, Lowell and Lawrence.
You can make any of these industries interactive by using the basic industry tracks. These are fixed-track segments that have properties associated with them that can be configured to load and unload various materials.
These are built into the content in TRS2006. I'm not sure about classics however, and are available for TRS2004.
Another creator that I recommend is Ben Dorsey. (bendorsey) He made a ton, and I mean a ton of wonderful industrial buildings that are dated around this period. They are mostly wood-sided, but they, for the most part, have interactive tracks built in that will change to any style and gauge track that you connect to it just like the basic-industry track.