one possible source is Underground Railroad press, they may have some < They have a lot of plans. here is a link. The NMRA has made a reprint of an old textbook called Lumber, I believe the authors name is Bryant. that will have a lot of info on sawmill layout, if not the actual plans, and is likely too big for the space most of us have available.
One problem we have as modelers, is that a sawmill big enough to need a logging railroad to feed it has a huge footprint
On my RR ( see logging in eastern TN on the DG CC & W RR in 1928 in this section) I did not have a plan. My dad had a lot of reference materials, and I looked at lots of pictures of mills, and borrowed elements of several to build my mill, and mill town.
There are some other resources I have in mind, but I will have to dig around in the cobwebby corners to try to get a handle on them, I'll share those if and when the memory resurfaces.
Sawmill plans will vary with the locality, the time period ( which will dictate the machinery used) and even the dominant species of tree to be cut. The Bryant textbook is an invaluable resource ( I have an original) The main determinant of the shape of the mill is the machinery, and the route of the logs through the machinery. the shape of building is just what is needed to keep the machinery out of the rain.
big determinants of what the mill will or ought to look like then is the location , time period, type of trees to be cut, and the size of the operation. Have you thought about those things? how much space do you have available? as I said, a proper sawmill is huge. on my RR I have the Mill and the planning mill up close to the wall so much of the complex is just suggested in the back drop. My sawmill town is over 18 feet long and two and a half feet deep in Ho, and I used some compression in places and left stuff out.
Thanks so much for the advice and info. I'm still in the planning stage. I would like to present the illusion of a mill but not get too big with it. I just need a frame of reference for scratch building a mill.
One way to get an illusion of a larger mill than you have room for is to do the mill as a flat along the backdrop. one of the best I have seen is used on the front page of the Yahoo model loggers group
this is a decent forum, as is the 4L group @ Yahoo. I much prefer the format here at Zealot, as over in the Yahoo sites, text is seperated from photos, so the kind of step by step text with photos for illustration is not possible over there.
With a mill's interface with a railroad, you have two main areas of interest, the log dump, and the lumber loading docks. In model railroads, often the emphasis is on the log dump, and the lumber loading ins minimized or even ignored. If you are modeling a log hauler < all you need is a log dump, a lumber loading operation will take more space. My RR is a Log and lumber hauler, so I have to model both. If you check out my thread, and DR. Tom's old C&S thread, you will see a lot of ideas, and get some feel for the other operations needed to support a logging operation (moving crews, supplies, machinery (animals, on earlier or more primitive operations), stuff that makes operations of a woods railroad much more interesting and more complex than they might otherwise seem.
Good luck, if you read through My DG CC & W RR thread, Dr. Tom's C&S thread, and the Bill and Tom's excellent adventure ( our club projects) you will be exposed to many years worth of information, some of it may be helpful. look through that stuff, we will be happy to help with specifics as you run into them.
You seem to have a time period, do you have a location, Tom and I do Eastern TN. most folks do west cost, which is easier, as the operations were generally later and better documented. It really helps if you can select one or two actual operations to use for inspiration, then you can use photos of a particular mill as inspiration. My mill was inspired by three or four, and as a result is somewhat of a mess. It looks good enough that no one notices, but I have used some elements of a single band sawmill design, and others from a double band saw mill, and I left out an important feature, a saw filling platform in the roof, so taking your inspiration from one mill will make sense, but you want to make that mill compatible with a time and place that fits your railroads theme.