Installing two large diameter casings under the Burlington Northern/Santa Fe Railroad for the expansion of a golf course. Safety was a major concern since the track was traveled by up to 120 trains each day. In addition, the expansion would also be adding more hike and bike trails in the area, so the safety of pedestrians eliminated the option of an above ground crossing.
For the first tunnel, Permalok delivered four 21-foot joints of 120” O. D. casing. When the initial tool configuration of segmented ram cones could not stand up to the amount of stress placed on it, Permalok fabricated a 120” pipe adapter that resembled an inverted bell, which proved to be successful.
After learning new lessons on the smaller installation, the crew began to work on the 138” job. Permalok provided pipe for the larger tunnel that had an O. D. of 138” and a 1.5” wall thickness. Each 21-foot joint weighed 46,000 lbs.
When installation was complete, the pipe forming the 148-foot long tunnel weighed 323,000 lbs., and when the final casing segment was in place, a new large diameter pipe ramming record was established.