A model railroad is in every way a miniature railroad. In fact, most have had to truncate some of their dimensions to fit available space. Just look at distances. A scale mile in O gauge 1/48 is 110 feet. It is 82.5 feet in S and 3/16" O27. It is 60 feet 8 inches in HO, and 33 Feet in N scale. How many home railroads have that much space? And that is just one mile! Modeling a railroad mainline in full scale would be almost impossible. A 50-mile route would take 5,500 feet for O scale, 4,125 in S. 3,330 feet in HO and 1,650 feet in N. Most home railroads’ longest dimension runs from 8 to 16 feet. While club tracks can be larger, few have a longest side reaching 100 feet. Obviously, distances must be truncated.
Unless you are a large club with several members running a massive pike at once, your operation is limited. There are real railroad resources which can help you develop a functioning pike in a smaller area. Short lines and branch lines are real railroads with a more limited scope than Class 1 railways. They handle less distance and fewer tasks than the big roads. For a model railroader, using them as inspiration can make a satisfying and realistic pike that can be handled easily by a lone operator. It does not matter if you want to model a Class 1 or smaller operation.
The smaller pikes can show you the way.
For one thing., you can get a feel for working in a more limited area with smaller facilities. There is the benefit of seeing how shorter distances are handled. You also find inspiration for designing your own small railroad. Operating in a scaled-down fashion, the methods of smaller railroads can easily be applied to your own home railway.
Your railroad can be a mainline pike, branch or shortline. Which ever you choose, short and branch lines can certainly help you put together a small railroad that works!
Also, check out the historical societies formed around various short, branch and bridge lines. In my region, the ones that come to mind are the Raritan River Railroad, Freehold branch of the Jersey Central, Middletown and New Jersey (formerly Middletown and Unionville), the Morristown and Erie, Hoboken Shore Railroad, and the Lehigh and Hudson River (a bridge line).
To give you an idea of how commodities affect your choice of equipment, here are soem examples:
If you are hauling pulp wood, expect to use gondolas. For paper, boxcars provide adequate protection from the elements. The potatoes and produce in Freehold were only going to be in transit for less than two hours, so boxcars were used. Longer hauls might require refrigerated cars. Sand and gravel tend to use hoppers. Brick would use gondolas are flat cars, depending how it was stacked and bundled. munitions would move in boxcars.
Sand, gravel, brick and coal emphasize pulling power rather than speed in locomotives. Potato trains require less power and so could accommodate more speed in their motive power..