A lot of areas here in the US have trails that used to be railroad lines. The easy grades, separated right-of-way, etc. all lend itself to them being created for public use. They're great to have.
But their condition can vary a lot. Some are paved, some have crushed class 5 gravel, others are marked as a trail but lack improvements or are missing bridges.
It's nice to see folks like @innisfree getting out and getting these trails mapped. IIRC when this trail was a railroad, it was part of The Milwaukee Road and abandoned when it went bankrupt in the early 1980s. Wisconsin DOT had bought it back then looking to keep rail service. That didn't work out but it worked well in the end since the land was kept for the trail.