Quoting from a post on the Frisco.org website, there's a ton of detail:
The Fairgrounds Branch (also known as (aka) "the Hill") was an interesting industrial switching area near West 31st Street and Southwest Boulevard, close to the state line border of Kansas and Missouri. In the Frisco's Kansas City Terminal Industry Schematics it is known as part of the 29th Street Industrial Area, Zone 3.That last sentence of the original post sums up what I'm aiming for. Now I have some company names to continue research on and narrow down an era when most of them might've still been receiving rail service.
The branch is located between the Frisco's Rosedale and 19th Street Yards. It starts at 29th Street Interlocking, under the I-35 overpass behind Ponak's Mexican Restaurant, curves southwest across Southwest Boulevard, passes and serves Schutte Lumber, starts uphill climbing across 31st Street, turns generally southeast and parallels Roanoke Road.
Climbing out of the Turkey Creek valley (prone to flooding) the line climbs in vertical elevation 80 feet in just under 1 mile. Close to the end of the line, after crossing West 34th Street, it stub ends near Karnes Boulevard. From here there is a switchback uphill to serve additional industries to the northwest that again climbs and runs on either side of Terrace Street.
In addition to the really neat area area around Schutte Lumber (with several switch backs and tracks inside lumber sheds) industries along the line included the Garfield Team Track, Paper Supply Company, Carthage Marble, W. C. Tingle, Pacific Mutual Door Company, Battenfield Grease & Oil Company, Safeway Bakeries, Motor Parts Distributors, Sherwood Chemical Company, Union Carbide, American Mineral Sprits, Southwestern Bell Telephone, U. S. Engineering, Swenson Construction Company, Ftyro Fabricators and Fred Wolferman Groceries. <edit> Additionally, I've found Columbia Bedding, Fairfax Bread Co., Western Electric, Sherwood & Co, Inc., plus Concrete Building Units Co. on a Sanborn Map updated through 1950. </edit>
Branching off the Fairgrounds Branch in the 29th Street Industrial Area is Zone 4 (aka "the Alley"). This spur takes off to the northeast on the south side of Southwest Boulevard. This line ran in an alley (hence the name) behind the buildings that fronted Southwest Boulevard, across from the Kansas City Terminal (KCT) Railway roundhouse.
Industries served on this line included the American Dish Service Company, Rite-Made Paper Converters, Hubbard's Imperial, Combs & Company, Bartlett Container Corporation, C. S. Tull Transfer, City Wide Brick & Supply Company, Koch Supplies, Roll Easy Door Company, K & K Sheet Metal, Gate City Petroleum (tank farm), Dairy & Creamery Equipment Company, Gresham Company, Anchor Roofing and Siding company, Foreign Car Auto Salvage, Webb Belting & Supply Company, Aero Plastics, American Steel Company (with overhead transverse crane), Texaco, Inc., Corbin Equipment Company, Hill Building Materials Company, A.P. Green Fire Brick Company, Skelly Oil Company, Roberts Furniture Company, Jianas Brothers Candy Company, R. L. Faubion Steel and Tank Company, Flint Ink Company and Funkhouser Machinery Company (including an end loading ramp).
Today only a short spur remains from the 29th Street Interlocking to serve Schutte Lumber. Many of the buildings, signs of track in streets and some of the original businesses listed above remain. This would be a great area to model in a relatively small space as it featured a great number of industries in a relatively small space, most types of freight cars served the different customers and would need only a switcher or two for power.
<<edit>> Corrected W.C. Triangle to W.C. Tingle, a flooring supply company.