Springfield is served by six railroads - AMTK, CN, IMRR, KCS, NS and UP. There isn't much local industry but there's enough train action to make it interesting. I'll try to break it down below:
AMTRAK runs ten daily trains on the Union Pacific's Springfield Subdivision, eight of which are Chicago - St. Louis Lincoln Service trains. The Chicago - San Antonio Texas Eagles are the other two trains.
CANADIAN NATIONAL runs a daily-except-Sunday local out of Clinton to serve customers and interchanges on the Gilman Subdivision between Clinton and Farmersville. CN has rights on the KCS to reach the ADM Grain elevator at Cockrell Station. Other customers are Illinois Valley Paving (former Sankey Construction), Contech Construction Products, Mid-States Warehouse (fertilizer) and Crown Mine III (Farmersville). Regular interchange is made with Illinois & Midland and Kansas City Southern.
ILLINOIS & MIDLAND recently downsized their Springfield operations (Shops Yard), moving the locomotive shop work to sister Tazewell & Peoria's Creve Coeur facilities. I believe the fuel storage tanks and depot have been razed. Rumor is most yard tracks will be scrapped. A switch engine is based at Springfield to perform local work (lumber re-load on yard property) and interchanges (mainly KCS, but also CN, NS and UP). It's unclear if this job operates beyond Springfield switching district limits, such as to Ellis where a Reed Minerals plant is still (presumably) served. Past customers like Solomon Colors and Thurman L. Flatt & Sons have sidings but haven't been served since c. 2000. Once a large customer, the Cargill Flour Milling plant closed in 2001.
On most days, IMRR runs a coal train (with UP run-through power) to the Dominion-Kincaid Generating Station east of Pawnee, with corresponding empties returning in the other direction. To reach it, IMRR excercises trackage rights on CN between Springfield and Cimic.
KANSAS CITY SOUTHERN's nearest "terminal" is at Roodhouse, at which an AM and PM roadswitcher are based. Usually the PM job gets to Springfield in the evening (after dark) on a few days a week. KCS serves the ADM Grain elevator, Brandt Conolidated, Freesen asphalt plant and plastic transload at Cockrell Station, and goes into Springfield to interchange with CN and IMRR at IMRR's Shops Yard.
NORFOLK SOUTHERN actually has a small yard in Springfield where about two or three local jobs are based. One "turns" to Decatur, the others go west (one to Jacksonville and Meredosia; the other I believe runs all the way to Hannibal - not sure though). The Formosa Plastics plant in Illiopolis is closed, permanently, it appears but fertilizer customers at Illiopolis and Buffalo still get service. The State Journal-Register is also gets some of its newsprint by rail. NS serves Brandt Consolidated at Curran, just SW of town. NS runs daily Detroit - Kansas City roadrailers, a Los Angeles - Columbus (OH) stack train joint with BNSF, and some auto parts, automotive and general merchandise trains through Springfield, amounting to something like a dozen movements per day.
UNION PACIFIC still uses Ridgely Yard to perform some local switching but most tracks were removed in the early 1990's by Southern Pacific. A local runs out of Bloomington Su, Tu and Th in AM, then the following day may continue down to Carlinville to switch Central Illinois Steel Company before returning north. The only customer served directly is Mid-States Warehouse, to which UP delivers an occasional potash train (which runs via the former C&NW).
An alternate-day Alton & Southern - Bloomington manifest train (MASBN/MBNAS) begins its cycle Monday and ends it on Saturday. Daily manifests MPRPB (Proviso to Pine Bluff) and MASPR (Alton & Southern to Proviso) use the Springfield Sub south of Ridgely, the old C&NW route (via IMRR trackage rights) north of there. These trains operate in second sections once or twice a week.
A Monterey Mine - Duck Creek coal train makes about two or three cycles per week, passing through Springfield. Unit grain trains coming out of Sterling and Allen Station (just west of San Jose) appear frequently, especially during the fall and winter months. Due to trackwork on the Jefferson City Sub in Missouri, frequent empty coal trains and even manifest MASNP have detoured through Springfield.
I don't claim the above is 100% accurate but it should be close. Hope it helps.