Page:NTSB - Railroad Accident Report - Derailment on May 25, 1989.djvu/9



Events Preceding the Train Derailment

Loading of Hopper Cars.—The Lake Minerals Corporation, an Owens Lake, California, company involved in the mining and shipment of trona, contracted with the Southern Pacific Transportation Company (SP) to have a shipment of trona transported from the Corporation’s rail facility in Rosamond, California (see figure 1), to the Port of Los Angeles. The trona was then to be loaded into a vessel destined for Colombia, South America. Lake Minerals’ customer had ordered 6,835 tons of trona. The contract with the SP specified that the railroad would provide 69 100-ton open-top hopper cars; Lake Minerals’ payment to the SP was to be based on 100 tons per car.

Because Lake Minerals Corporation did not have rail facilities at its Owens Lake plant, the trona was shipped by truck from there to the rail facility at Rosamond, where the trona was loaded into the open-top hopper cars by a loading contractor hired by the Lake Minerals Corporation. The Lake Minerals Corporation had shipped trona by rail to the Port of Los Angeles on only one previous occasion. The superintendent of Lake Minerals Corporation testified that on that first shipment the company had averaged 88 tons per car when the contract had also called for 100 tons per car. He stated, "We ended up with a significant shortage at the port and did not have enough material to fill the vessel," and "…we ended up with a dead freight charge." For the second shipment, Lake Minerals Corporation requested that the loading contractor install a sensing device on the front-end loader to measure the amount of material that was being loaded into the cars. To test the accuracy of the sensing device, a truck was loaded with the trona and weighed on the truck scale at the loading facility. The device was checked for accuracy after about half the cars had been loaded. The superintendent stated that he was satisfied that the device accurately weighed the loads. He further testified that "we were very concerned with being as accurate as possible." In addition to expressing concern that they did not underestimate the amount of trona loaded, he stated, "At the Port facility there is no way to handle the trona if we had excess material and the vessel was loaded. We would have had to dump it on the ground and haul it back, and we wanted to avoid that at all costs."