The first railroad to cross the Mississippi River was the Mississippi and Missouri (M&M) Railroad in 1856.
When the Chicago, Rock Island & Pacific (CRI&P) was formed in Iowa, it purchased the M&M in 1866. It was authorized to build from Kellogg to Des Moines, arriving in 1867. With clear title, including land grants, the Illinois and Iowa lines were consolidated.
The railroad was finished to Dexter in August, 1868, and the depot was erected in December, same year.
Construction to Council Bluffs was completed May 11, 1869, the day after the UP-Central Pacific tracks were joined at Promontory Point, Utah.
Trains
When Ruby Blohm was girl in the early 1900s, a passenger train came through Dexter about every two hours, going one way or the other. Folks could go to Des Moines to shop and be back in Dexter about 6:00 in the evening. She said that a local reporter met every passenger train to learn where folks were going, so the Dexter paper had lots of local news items. Some passenger trains stopped at every town. The Flyer stopped only if a station agent had wired ahead for it to make a stop. Dexterites were always curious to know why and for whom a Flyer would stop in Dexter.



Everything that came into Dexter had to come on a freight train. There were two dray lines to haul groceries that arrived in barrels and bags. Grocery stores had their own coffee grinders, operated by a big wheel by hand [like at Ike Godsey’s Store in the Walton series]. They had to weigh and grind the coffee.
Ruby Blohm: Mexican families were brought into town to work on the railroad bed. Several boxcars were parked on the siding for them to live in. [During the 1920s, Doris Wilson went to school with a girl named Tina Doll Navitidad who lived there in a boxcar.]

In September 1957, the Dexter depot became history.
The Dexter Museum has a display about the Rock Island Railroad, with items loaned by Rod Stanley.
Sources: 1870 clipping about Dexter; 1968 Dexter Centennial history; memories of Ruby (Blohm) Neal
Steam locomotives still capture a great sense of nostalgia!
I sure agree with that!