elevation, and the hole was backfilled. Calnev personnel testified that as a result of these soft dig excavations, the pipe was exposed from the 10 o’clock position to the 2 o’clock position at each soft dig excavation and that before the holes were backfilled, the pipe was inspected for damage; no damage was observed at any of these locations. According to Calnev, the purpose of the stakes was to provide information to SP regarding the location and depth of the pipeline when SP began removing the trona from the derailment site. SP was advised by Calnev to preserve the stakes until all grading of the area was completed. Calnev’s manager of operations observed, based on the placement of the stakes, that the pipeline depth below natural ground varied from 4 to 8 feet through the derailment area.
Calnev’s manager of operations testified, "On Tuesday, the 16th, we had by then accomplished full trenching [8-foot-wide path] over the top of the pipeline in the affected area. We had removed or had caused to remove any debris that we had found. We had investigated every area that debris had penetrated the native soil. …Based on that assessment…my opinion was that the pipe had not been damaged by the train derailment." Clearance was given at 11:28 a.m. by Calnev for the restart of the pipeline; operations were resumed about noon on Tuesday, May 16. The pressure was initially increased to about 1,200 psig, at which point, according to Calnev’s manager of operations, the dispatcher on duty watched for any signs of loss of pressure in the system. The pressure held constant for about 15 minutes after which the pipeline was brought up to normal operating pressure (about 1,600 psig) and regular operations were resumed.
The Safety Board received conflicting testimony regarding a request to expose completely the pipeline prior to resuming operations. The incident commander (San Bernardino deputy fire chief) testified he requested that Calnev fully expose the pipeline in the derailment area. According to Calnev’s manager of operations, such a request was not made by either the San Bernardino fire department or the SP. He did state that several options had been considered, including the use of an internal electromagnetic inspection instrument for detecting defects in the pipe wall and a hydrostatic test of the pipeline. He stated further that it would not have been practical to run the inspection instrument through the line because "…the line would have had to have been brought up to full operating pressure and operated in that state for about 5 days to push [the instrument] through to the other end." He elaborated that because of the mountains between Colton and Las Vegas [the end of the line], it would be necessary to operate at full pressure just to get the instrument over the mountains. Calnev’s manager of operations also stated that, "[A] hydrostatic test would have been performed had there been some doubt as to the integrity of the pipeline. We found no reason to doubt the integrity of the pipeline upon completion of our inspection and did not perform a hydrostatic test."
SP contracted with the International Technology Corporation (IT) to have the trona removed from the derailment site; removal of the trona began during the afternoon of May 16. According to the project manager for IT, cleanup of the trona began in the area closest to Duffy Street and then continued through the derailment area from south to north. Equipment operators testified that to remove the trona that had been piled east of the