LONDON (Bentley Year in Infrastructure 2013), Oct 28, 2013 - Driving a train into a tunnel at full speed is an act of faith. As that little hole in the mountain approaches, you can only hope the engineers who designed the tunnel and the men who laid the tracks did their jobs well. Surely, all the other trains that have entered before yours have also emerged from the other side. Intact. Unscathed. Whole.
photo from Lewis and Clark Train Club
With the 8 mile long Cascade Tunnel, the longest tunnel in the United States, this is not necessarily the case. Built in 1928 before the advent of double stack container cars, corners of trains had been scraping the insides of the tunnel. The tunnel was notched to prevent this problem. It wasn't enough. The double stacked container cars were creating showers of sparks as they plowed their own, even deeper channels.
The obvious solution was to increase the depth of the notches. Makes sense, right? The tunnel owners (BSNF) balked at the $10 million cost to deepen the notch along the entire 8 mile length and hired JL Patterson & Associates, Inc. to suggest an alternative solution. Engineers at JLP lowered their gaze from the damaged roof of the tunnel to the track. Could the placement of the track, perhaps its shift over time, be causing the scraping?
To prove their theory, JLP needed some serious technology. First, they would have to remap the tunnel. With the tunnel being under thousands of feet of rock, GPS wasn't going to help inside. They had to create a survey network throughout the tunnel length, anchored by GPS-verified locations on each end. Then they set to work constructing a 3D model of the rail and the tunnel.
A 3D laser scanner was driven through the tunnel and generated a point cloud model of the tunnel. The good news was the scanner generated 2.5 terabytes of data. That was also the bad news, jokes the JLP engineer who is presenting the project as finalist at Bentley's annual parade of top projects. Point clouds need to be converted to surface models in order to make themselves useful -- visually or for analysis. And also, the traveling scanner would need to be aware of its own position. Knowing its position and relating that to the dimensions of a double stacked container car should allow them to define a clearance between train and tunnel-- or lack thereof.
Who can help with that? Enter Bentley Systems. Bentley's Rail and Transit software seems tailor made for such an application.
JLP credits Bentley Rail and Track to help have saved BSNF save $9M of the projected $10M cost estimated for the original plan, a whopping 90% cost reduction.