Lincoln Fire Chief Dave Whitt said Monday the cause of a propane tanker rail car fire last week was "undetermined, unable to rule out mechanical failure or human error."

Whitt's preliminary report on the tanker car blaze that resulted in the evacuation of approximately 4,800 homes in the city for two days leaves unanswered why the fire erupted that day.

It could be some time before federal officials release a possible cause. Whitt said he understands that investigators with the Federal Railroad Administration want to move the burned rail car to a location where they can closely examine the tanker.

Whitt said inspectors will look at valving on the rail car and may conduct more interviews.

"They did some interviews on Saturday," said Whitt. "They may have to do some more. It's pretty simple: There was one guy up there when it started. I don't know what the result of that interview was."

Lincoln Fire Department will not investigate the propane car fire, Whitt said. Even though the fire occurred in Lincoln's jurisdiction, he said, it was appropriate to place the investigation in the hands of federal authorities who have more experience with railroad fires.

"I would yield to the experts: the Federal Railroad Administration and the Public Utilities Commission," said Whitt.

Firefighters responded about 12:30 p.m. last Tuesday to emergency calls of flames shooting from the top of the full 30,000-gallon propane rail car parked on a spur off the Union Pacific main line. Authorities evacuated neighborhoods within a 1-mile radius, including the city's downtown, while unmanned hoses were trained on the burning tanker to cool it and keep it from exploding.

Experts were brought in from Texas to conduct a risky "hot tap" operation to divert the liquid propane from the tanker into a dugout pond where it could be safely burned. But before that operation was undertaken Wednesday night, firefighters saw that the flames were diminishing. They instead pumped water and an aqueous foam into the tanker to force out the remaining vapors and allowed the fire to burn itself out.

Northern Energy, the firm that owns and operates the propane storage facility in Lincoln, announced Monday that it has set up a centralized call center to handle claims from people affected by the evacuation last week. People may call (855) 828-5137.

Northern Energy is an operating subsidiary of Helena, Mont.-based Heritage Propane, a national propane retailer.

"The strength and character of this community shone brightly during a very difficult time, yet we know that many of you made great sacrifices during the evacuation effort," Eric Beatty, Heritage Propane's general counsel, said in a written statement.

"If you were affected by the evacuation effort, please contact us."

© Copyright The Sacramento Bee. All rights reserved.

Call The Bee's Bill Lindelof, (916) 321-1079. Staff writer Cathy Locke contributed to this report.

• Read more articles by Bill Lindelof