The Mid-Michigan Railroad (formerly the Grand Rapids Eastern) used to go east everyday to Ada, Lowell, Ionia and / or Greenville. Their major customers to the east included Amway, King Milling, Michigan Wire, American Bumper (now Meridian) and Electrolux. At one time, 1 crew worked Greenville to Lowell and return and 1 crew worked GR to Ionia and return. Today, the Electrolux plant is gone and Meridian ships exclusivley by truck and I don't see that changing. The MMRR still serves Rosewoodworks & Precision Poly on Oak Industrial Drive, King Milling and Michigan Wire. They get occasional cars of fertilizer for Greenville & Ionia and a car or two of lumber for Standard Lumber in Ionia. They rarely work 5 days a week, usually 4 and only go as far as needed. They go as far west as Marne with their biggest customer that direction being Van's in the smaller Meijer warehouse on Walker Ave.
Short version: They used to go east 5 days a week, now it may be less than that depending on traffic
Hope this wasn't too much detail