The Town has received comments and suggestions to install a bridge or tunnel across the tracks. To help the public understand why these options are considered infeasible, we have included additional information for the tunnel configuration. Tunnels would require 16.5 feet clearance beneath the tracks for trucks. This would create roadway grades in excess of 27%. To provide an idea of how steep this is, Northwoods Boulevard face is 8 to 10%! Bridges over the tracks are even steeper, requiring clearance over the tracks of about 23 feet. The reason the Mousehole and McIver undercrossing areas work for grade separation are due to the existing elevation differences between the roads and the tracks. McIver undercrossing required the switchback down to West River Street to make the grades work even with a significant elevation difference.
We have also receive many comments on the costs of these options, assuming that is why they are not considered as an alternative. At this point in the project, cost was not a factor in selection of the best alternatives. While bridges or tunnels are very expensive, the main objective was to determine the best solution for the intersections and to find additional funding through grants or other sources if necessary.
Therefore, due to the steep grades required for these options, we considered them infeasible.