The inexplicable happened last week and there likely won't be any official answers for a year or more as investigators unwind what happened when two CN Railway ore trains collided north of Two Harbors.

The accident happened about 4 p.m. Thursday as an empty ore train coming from the docks in Two Harbors collided with a full ore train headed south near the Highland Lake siding. Each were pulling more than 100 cars. The empties smashed into the third engine of the northbound train, clipping a corner off and showing the force behind the impact Friday as crews worked to pull the six engines off the tracks at the Boomers Road crossing a few miles west of Highway 2, 12 miles north of Two Harbors.

Five crew members were injured. One remained in a Duluth hospital this week with broken bones.

Investigators with a railroad union, the National Transportation Safety Board, Federal Railroad Administration, and CN were on the scene this week. The investigation included a reenactment of the crash.

The line reopened late Friday afternoon as CN continues what it has called a good year at the docks with shipments up.

CN spokesman Patrick Waldron won't go into details about the accident or the condition of the crew. Crews are cutting up the damaged engines and ore cars along the line this week. "The 13 cars and three locomotives will be scrapped and hauled away in coming days."

Waldron said no one from his company is going to talk about the accident until the facts are in.

Scott Schendel of Duluth remained in good condition Monday at St. Mary's Medical Center, said hospital spokeswoman Kim Kaiser.

All five crewmen originally were transported to Lake View Memorial Hospital in Two Harbors. Three of the men were released Friday and one was released between then and Monday.

The other men released from hospitals in Two Harbors and Duluth include conductors Kevin Weaver, Michael Anderson and Miles Reimer and engineer Dan Murphy. Anderson, Reimer and Weaver are members of the United Transportation Union, according to the union. Schendel and Murphy belong to the Brotherhood of Local Engineers and Trainmen, said Keith Stauber, general chairman for Division 163 in Proctor.

The wreck

The train heading north had three locomotives and was pulling 118 empty cars at the time of the crash. As the two trains hit each other, one locomotive in the northbound train derailed, but they all remained upright. Behind them, five empty cars spilled off the tracks in an S-shape - two on one side and three on the other side of the tracks, with one car completely on its side. The train had just rounded a gradual western bend.

The southbound train, with three locomotives pulling 116 cars full of taconite pellets, had two locomotives and eight cars derail, spilling taconite. The speed of the trains at impact, considering track rules and that the full train was just pulling out of the siding, are speculated at under 30 mph but the weight of the trains makes any impact significant.

Crews from CN, including environmental teams, spent the night cleaning up the site and the cars and engines were removed from the tracks by Friday afternoon. A train with empties left Two Harbors at 4:45 p.m. Friday.

Local response

Lake County Sheriff Carey Johnson said local police were cleared from the scene as soon as the five injured people were removed. The clean-up is "up to CN, it's on their tracks," Johnson said.

Police would be more involved if the accident included public right-of-way or a train hitting a car at a crossing.

Deputies responded as well as State Patrol, Lake and St. Louis County rescue teams, fire crews from Two Harbors and Brimson, and three Lake County ambulances.

Two of the ambulances were used. A helicopter landing sight was set up on Highway 2, just east of the crash site, but Johnson said it wasn't used. There was also a helicopter site at the Two Harbors Fire Department that was used to bring two of the injured to Duluth.

On Sept 14, county emergency crews worked with CN on a disaster drill at Agate Bay. It was a simulated fuel spill at the docks CN uses to fill ships with iron ore pellets.

While protocol set up for that drill called for a command post and a coordinated response from responders, the scene Thursday was about making sure injured people were taken care of, Johnson said. "It's hectic right away and we all work together. It depends on who the first responders are."

How could it happen?

Mel Sando, who runs the Lake County Historical Society at the depot in Two Harbors, said he and local train historian Todd Lindahl were just talking about train traffic on the old Drummond Line the day before the accident. They talked about how remarkable it was that there weren't more accidents on the historical spur line for lumber trains, which at one point numbered 30 a day going to and from Two Harbors.

"And back then they're using stop watches and speed gauges (on the tracks)," Sando said. He, like many train enthusiasts in the area, found it hard to believe how two trains could collide.

The section of track where the accident happened Thursday, and all the way south to Two Harbors, is considered "dark," meaning there isn't centralized traffic control from CN's traffic control center in Homewood, Ill. That section isn't monitored or controlled by computerized systems. Train movement is communicated via radio with back-and-forth messages on what section a train is on.

Lindahl said he can recall many single-train mishaps in the county, derailments or car failures, but not a head-on accident.

A recently retired trainmaster, conductor and dispatcher for Canadian National described how crews and trains typically operate on those tracks.

"The trains leave Two Harbors and go to various mines," he said. "They average 116 cars, mostly three engines. That's standard.

"They run empty out of Two Harbors and go to the mines. They load and return the train to Two Harbors in an 11½- or 12-hour shift."

Most trains are operated by an engineer and a conductor and sometimes a train might also have a brakeman along. CN officials said one of the trains involved in Thursday's accident had two employees on board and that the other had three. One was a trainee.

"The engineer is in charge of safe handling of the train," the retiree said. "The conductor is the one who does the radio work with the dispatcher, gets the track warrants -- the authority to run on the track. When they get up to the mine, the conductor is in charge of watching the mine load it. He's in charge of the paperwork."

A track warrant is clearance that a section of track is clear and that a train may proceed on it. It's common for a southbound, loaded train to pull off on the Highland Lake siding to be weighed. If an unloaded northbound train is in the vicinity, the loaded train's track warrant would allow it to return to the main track only after verifying that the northbound train had been cleared.

"They physically read the engine number (of the northbound train), and then when they know it's the train they were supposed to meet, they can go," he said.

Northbound trains, traveling empty, typically travel up to the limit of track speed, which is 35 to 40 mph, although they may go slower climbing the hill out of Two Harbors. Southbound trains don't usually travel up to track speed.

"Loaded trains have many hills to conquer where they can't go nearly that fast. They may be going 8 to 12 mph (in those places). They're pulling up to 10,000 trailing tons," he said.

When two trains are on the same track, it's typical for one train to pull off on a siding to let the other pass, he said. "It happens every day in a million places," he said. "It's called a 'train leap.'"

"The big fight is going to be why did that train leave the siding?" said William Jungbauer, an attorney who has been representing injured railroad workers for 33 years, and whose Minneapolis-based firm has been representing railroad workers for 80 years.

"The crew members are probably going to say that the dispatchers told them to come into town," Jungbauer said. "The railroad is going to say 'I don't care what the dispatcher said, you still have to comply with the rules of who's allowed to be on what track and what time.' "

Rare event

Head-on train accidents are uncommon, said Jerry Bakke, an independent railroad industry consultant in Duluth.

"They're fairly rare," Bakke said. "We investigate hundreds of train wrecks, derailments and accidents a year. The occurrence of a head-on is rare. ... Any time that happens, generally there's a communication gap somewhere."

The fact that the trains met near a curve in the track suggests that the engineers likely had little time to react before the collision, Bakke said. And stopping a train with more than 100 cars, even if empty and moving slowly, requires significant distance.

Investigators with the NTSB and the Federal Railroad Administration will interview the crews and trainmasters and examine maintenance records of the trains. Both federal groups have targeted "dark territory" in the past decade, calling for more automated traffic control to take human error out of accident equations.

"The first thing you're always looking for is a cause," Bakke said. "In this situation, it's probably not going to be too difficult for them, as opposed to a mechanical (issue) or a rail brake."

Like airplanes, locomotives are equipped with so-called "black boxes," or event recorders, that indicate such things as speed, use of throttle controls and use of brakes at the time of accidents.

A final report on the cause of the accident might not be completed for 12 to 18 months, said NTSB spokesman Keith Holloway. But he said preliminary factual findings on the crash will periodically be released by the board.