The only significant gap in the trail between Columbus and Cincinnati (with the exception of the 5-mile approach to DT Cincinnati) was closed in September with the opening of a new bridge across the Little Miami River:
https://www.wcpo.com/news/local-news...g-construction
So now approximately 122 of the 127 miles between Cincinnati and Columbus are complete. The wheels are finally turning to build the downtown approach, which will parallel a very lightly used railroad track (2-3 trains per week) on an almost entirely grade separated route between Lunken Airport and DT Cincinnati.
This rail corridor was rebuilt in its current form as a two-track fully-grade separated route around 1912 and features a bunch of riveted overpasses, pedestrian underpasses, and other old-school stuff. It was big-time for its era.
The line used to connect across Cincinnati's riverfront but that link was severed in the late 1990s. It now has just two customers and operates as a spur. The second track is still there but probably hasn't been used since that time. The bike trail is going to take the place of the disused track and will be separated from the active track with a fence.