ANCHORAGE - A buildup of ice and snow on the tracks caused the train derailment last month that resulted in a 100,000 gallon jet fuel spill, Alaska Railroad officials said Monday.
``I know it seems strange that a 263,000-pound locomotive can be moved off the rail just by snow and ice,'' said Ernie Piper, the railroad's vice president of safety and environmental compliance. ``We had snow and ice forming a solid surface at the same level as the track.''
The southbound fuel train of 53 tank cars and four locomotives derailed early on Dec. 22 about 36 miles north of Talkeetna. Three locomotives and 15 tank cars went off the tracks, spilling jet fuel that had been loaded at the Williams Alaska Refinery in North Pole.
The train previously had moved off the main track and onto a siding to allow a northbound train to pass. The problem began as the train was backing out of the siding and onto the main line. One of the rear wheels on the second locomotive slid off the track, Piper said. The train was moving south on the main line at about 30 mph when the train derailed.
``We found a mark where the locomotive wheel crawled over the top of the rail,'' Piper said.
The investigation found no defects with the track or road bed. The locomotives and cars were all in good shape, and the train crew did their jobs properly, he said.
``It was a confluence of sub-optimal conditions, a backing movement, the heavy snow and the ice buildup.''
Piper said changes made since the derailment are intended to minimize the chances of a similar accident.
Among the changes, loaded fuel trains headed southbound have the right of way over all other trains for at least the next four months. In addition, crews are making more frequent track inspections.
``Indeed, we can prepare for these things by increasing our track inspections and by broader snow removal,'' Piper said.
Efforts to clean up the spill continued Monday. Crews hoped to have the last of the fuel from the derailed cars off-loaded by Monday night and to remove the damaged cars so the snow and soil underneath can be cleaned up.
``We're still looking at a pretty tight area of contamination,'' Piper said.