I had never heard of the Tunnel marathon until Herbert wrote about it. It says there is over a 2,000 foot drop from the start to the finish with an consistent downhill grade of negative 2.2%. Given the downhill course and the fact that it is a point to point course which would most likely have a consistent west wind I was surprised that a course like this would be eligible for Boston qualifying?
Any idea what the time savings would be for a typical 3 hour marathoner?