Union Pacific railroad's "failure to maintain its track and track equipment" caused the June 3 oil train derailment that sent fireballs into the sky near Mosier and oil into the Columbia River, a federal agency has concluded.

In a preliminary report [PDF] issued by the Federal Railroad Administration this morning, investigators have confirmed that the accident, in which 16 oil tanker cars derailed and caught fire, was likely caused by broken "lag bolts," which made the track's rails stray too far apart. And the FRA concurs with the Oregon Department of Transportation, which has said that those broken bolts are virtually undetectable in routine inspections. You've pretty much got to have employees visually inspecting track to ferret them out.

"Broken and sheared lag bolts, while difficult to detect by high-rail, are more detectable by walking inspection combined with indications of movement in the rail or track structure and/or uneven rail wear, and are critically important to resolve quickly," the report says.

The finding comes as Union Pacific announced yesterday it will resume oil train traffic through the gorge this week. That's despite pleas from ODOT to the feds that oil trains be put on ice until assurances can be made that broken bolts aren't an issue on other segments of track.

In the wake of the June 3 derailment, a growing chorus of officials have called for an and to, or at least a break from, oil train traffic, but they're powerless to stop it.

Update, 1:30 pm: Gov. Kate Brown just issued a statement calling for a halt to oil train traffic in Oregon until safety concerns can be addressed. It's the strongest position we've heard from Brown on the subject. EDIT: Brown made a similar statement in an editorial in the Oregonian earlier this month.

Here it is:

"The Federal Railroad Administration's preliminary Mosier derailment report calls attention to serious safety concerns and the need for improved track inspections. I expect the final investigation report to be completed quickly and again call on rail operators to halt oil trains in Oregon until the strongest safety measures are put in place by federal authorities to protect Oregonians.”

Original post:

While today's FRA report blames faulty track maintenance for the crash, in also notes that if the train had been equipped with better brakes, "two fewer tank cars may have derailed, and one less tank car may have been punctured."

The report resulted in an immediate release from Oregon's US senators, Ron Wyden and Jeff Merkley:

“The preliminary findings released today by the Federal Railroad Administration confirm the deep concerns we have regarding track safety in the Columbia River Gorge," the statement says. "Union Pacific has not done enough to regain the confidence of Oregonians shaken by the Mosier derailment to restart oil shipments through this area.”