The CM&N was also working on building a mainline to Chicago from Freeport at this time.
In Freeport, the line met with two other lines, an Illinois Central line south towards Cairo, Illinois; and another IC line west towards Iowa.
As the line continued north, it had to transverse the increasingly harsher terrain as it got closer to Madison. Because of this, a tunnel was required east of New Glarus, Wisconsin.
The line was completed by 1888, and began branch line operations.
In Madison, the line met with a Chicago & North Western line and a Milwaukee Road line, providing connections to places north.
The line had been operated as an Illinois Central Line since its completion, but the CM&N finally became a part of the Illinois Central in 1903.
IC continued to operate this line as a branch line. The IC became part of the Illinois Central Gulf in 1972, after a merger with the Gulf, Mobile & Ohio.
The ICG abandoned the line in 1985, and the Wisconsin Department of Transportation decided the line was of critical importance.
The Wisconsin & Calumet was contracted to operated the line, and continued with moderate success until 1993, when the tracks were embargoed.
Between 1993 and 1999, the line was used for motor car enthusiasts, with hope of returned freight service.
This service would never return, and the tracks were removed in 1999, and the state of Wisconsin and Stephenson County purchased the line.
In Wisconsin, the line is currently the Badger State Trail, which heads directly into Madison. One short stub of the old line remains in Madison.
In Illinois, the Jane Addams Trail uses the line between Freeport and the State Line.
This tunnel is the largest landmark on the Badger State Trail.
As the darkest tunnel in Wisconsin, it holds the title due to the large curve in it. This prevents one from seeing from end to end.
Surprisingly, it is also considerably shorter than any of the Elroy-Sparta Trail tunnels; yet longer than the Hustler Tunnel, the other notable tunnels on Wisconsin Trails.
On the south portal, a partially concealed date confirms the date of 1887.
The tunnel is best accessed from Tunnel Road. Much of the interior of the tunnel either contains a rough cut of stone, or a brick lining.
Some sections also contain a concrete lining, as well as a reinforced steel lining added after the trail was constructed.
The south portal is a stone construction, while the north is a brick construction. Both are approached by sharp limestone bluffs on either side.
The tunnel here is necessary to go under a large ridge, which is common in the Driftless Area. This explanation is why Wisconsin had nine tunnels at one time.
On top of the tunnel, the land is used for farming. However, a few lucky landowners have houses on top of the ridge as well.
The author has ranked this tunnel as being moderately significant, due to it being one of the newer tunnels in Wisconsin.
The photo above is an overview of the South Portal.