i’d have to say a paper mill— there was an article about one in MR a few years back.
I am gathering materials to model a large urban soft drink bottling and distribution plant. In bound would be Corn Syurp (funnel flow tank); sugar (air slide hopper); phosphoric acid (tank or box car); citric acid (tank of box car); and CO2 gas (tank);
Pepsi web site has infornation concerning major ingridients in their products.
Outbound shipments of soft drinks and soft drink mix is by truck not rail. Next to the plant will be another small company which makes the plastic containers and receives plastic pellets by rail. (covered hopper) In addition, cans are punched from sheets of rolled alumimum. (box car or coil car).
Mack79 here is an idea for a lineside industry for your self type layout. Walthers’ magic pan bakeries commerical bakery would be good industry as it would have more than one kind of freight car. You would have airslide covered hoppers of flour and sugar, 40 foot funnel flow tankcars of corn syrup, 54 foot funnel flow tankcars of vegetable oils (cottonseed, canola, sunflower, corn oils, etc), and boxcars taking out bound boxed baked goods.
A major brand cannery complex would fill the bill! Especially if it had an attached can plant and maybe a glass plant, too! The old Hunt’s cannery in Hayward Ca. was such an industry. The United Can division got boxcars and flats of tinplated steel coils on pallets for it’s can and end production lines. It also got boxcars for shipping out cans, ends, and can-making machinery (another on site division) to other plants and customers, and put out gondola loads of scrap tinplate. The cannery got all kinds of cars of various fruit and vegetables, tank cars of corn syrup, and shipped boxcars of cased and palletized can goods to distributors all over, and the glass plant at the other end got hoppers of sand, and shipped out cased palletized loads of bottles and jars, besides the catsup that was pumped overhead pipeline across the street filled and cased over there. It was almost a mile long complex of buildings, having a siding on each side of the main and several spurs off them.