Hi,
Quote
Rich Muth
The ascent in the tunnel is 2.57 feet from the west portal to the apex and 27.2 feet from the east portal to the apex.
The vertical clearance in the inside of the tunnel is about 14-15 feet (I do now know the exact distance) the floor of the tunnel rises about 2.5 feet from the west portal before descending. If the height clearance int he tunnel is 15 feet, then the there is at least 12.5 feet from the top of the west portal to the apex. In other words, it is an ascending tunnel from east to west with a small pocket of air that is about 2.5 feet deep at the apex.
I suspect that other items governed the placement of the apex inside the tunnel. Drainage has already been mentioned. You really do not want water flowing through a tunnel. When it rains and floods (cloud burst) there is not much room in the tunnel in the ditches for the flood waters to go before the tracks flood. in many places, when a tunnel of on a steady grade, there are catch basins and culverts on the uphill side of the ditches along the track to get the water away from the tunnel.
Another item might be the type of geology that was found. Hard rock, flaky rock, shale, etc. Water is a powerful enemy, strong currents through a tunnel can erode the sub-grade. Not a desired result.
There may have been other reasons (N-S, E-W) for the tunnel to be built so.
Others have commented on these. Best rule of thumb, keep flowing water out of tunnels when possible.
Doug vV
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