St. Clair County in Illinois is home to this rail-with-trail as it travels from Belleville to Swansea. Though only 7 miles in length now, there are plans to extend in each direction to the next train station thus making it accessible to six stations. The southern end runs briefly through a sub-division, but construction is underway to move it alongside the track and build an overpass to avoid a busy street. The train travels all the way to St. Louis' Lambert Field airport.
The trail is mainly flat with some rises and a few overpasses and underpasses to negotiate. Currently it ends at Memorial Hospital in Belleville on the north and South Western Illinois College on the south. Below you see the train passing as it speeds by. The trains are electric and quite quiet as they speed past, and they allow you to ride the trail with your bike if the need arises.
The trail is equipped with these emergency call towers at regular intervals.
The Richland Creek Greenway Trail travels along the creek and takes you though seven Belleville city parks. Currently it is in two un-connected sections and the trail totals about 4 miles. This bridge is just past the water treatment facility.
Here's the map for the trail.