OKI has planned to incorporate the Wasson Rd. railroad into a regional transit plan since the 1970s. After Norfolk-Southern abandoned the line in 2009, a plan to convert it into a paved recreational trail appeared in 2011. The problem with this proposal is that there is not enough space for a double-track railroad and a paved rec trail on the available 30 foot right-of-way in the area between I-71 and Paxton Rd.
This means if we are to have both the transit line and the paved rec trail, the line must be built in a cut-and-cover subway tunnel between its bridge over I-71 and the Hyde Park Kroger, a distance of about 6,500 feet. For certain, an underground station would be required at Edwards Rd., and if the tunnel must be extended as far as Marburg, at least one more underground station. Although such a tunnel would conflict with few utilities, and no building underpinning would be required, it would add at least $50 million to the project cost, and perhaps $100 million or more.
This drawing shows the tunnel with dashes, and station locations in white:
Here are photos I took in 2007, when the line was still active. As is obvious from these photos, there is hardly space for a parallel railroad track (the existing tracks would be removed and new tracks built to either side), let alone the 40-50 feet necessary for a double-track line and a 10-foot rec trail:
Near Paxton Rd.:
These photos of the gulch east of Paxton show that retaining walls will be necessary along Wasson Rd. and/or the private land south of the ROW in order to double-track the line. The rec trail could probably be built here at street level, with a railing at the top of a retaining wall down to the tracks:
I'm seeing a manhole down there on the right. Does a utility line cross the line at this point or does it parallel the entire line? If so, add another $10 million to the tunnel cost:
Passing over Red Bank Rd.:
So in summary, by increasing the cost of the Hyde Park section of the Wasson Rd. transit line by $50-100~ million, the tunnel means miles of construction east of Red Bank Rd. will be temporarily sacrificed. Does this mean the line gets to Fairfax but not Mariemont? Mariemont but not Terrace Park? There's no way to know that today. But considering the glacial pace at which rail transit projects proceed, the neighborhood left without service might wait a decade or more.