Sources suggest that the cow tunnel is located at Webster Street and the tracks.
There is also another tunnel further east, south of Seager Park, but when the locals refer to the cow tunnel, the Webster Street tunnel is the one they are thinking about.
As Naperville grew and neighborhoods sprung up around the railroad tracks, pedestrians and bicyclists took over use of the tunnel. The underpass remained open until the 1970s when then-Mayor Chet Rybicki boarded it up to stop any "hanky-panky" from going on, as local lore tells it.
In latest buzz, residents want to reopen Naperville 'cow tunnel' for pedestrian access. Find out more at Chicago Tribune.