History of Nebraska, Chapter 33, Railroad Construction , page 682
"At Valentine the Fremont, Elkhorn & Missouri Valley
till 1885, during which time, or before it commenced building again, the
road was sold to the Chicago & Northwestern railway company, and its
future extensions were under the direction and ownership of that
corporation. In 1885 it was extended to Chadron, and from Chadron to
Buffalo Gap, South Dakota; in 1886 from Buffalo Gap to Rapid City, South
Dakota. In September, 1886, another branch was completed and opened from
Fremont to Wahoo, and on October 25, 1886, the same branch was completed
and opened to Lincoln."
"Another line was completed and opened December 6, 1886, from Scribner
to Lindsay. The next year, 1887, this line was extended through Boone,
Stanton, and Madison counties, to Oakdale, the then county seat of
Antelope county. There it intersected and connected with the main line."
Below is 1893 Rand McNally railroad map, with locations Buffalo Gap and Chadron highlighted. This shows the lines under the old name of Fremont, Elkhorn & Missouri Valley RR. Usually a town sprang up at every water stop (15 miles) along the track, so this stretch was pretty desolate.