An MBTA spokesman said police are still investigating how the person came to be on the tracks before being hit by an inbound train shortly before 4 p.m..

Shortly after 4 p.m., a rider on one train e-mailed UHub:

Train stopped due to what the conductor said is an apparent suicide between the two stops. He said the police are going to be on the scene for a few hours, so now we're waiting for the train to turn back to West Concord to disembark the train.

MBTA Transit Police report on an incident at 8:15 p.m.:

An Eastbound MBTA Fitchburg Line train struck a trespasser on Track 1 approximately 200 yards east of the Route 2 Bridge in Concord, MA. The person struck was pronounced deceased.

Police report the victim was a white woman, between roughly 18 and 22.

You know it's bad, Lee Ann Hooley tweets this morning, when the conductor announces "If you do need to get into town quickly, I suggest you drive."

Hooley and AsianKerr were among the hostages this morning on the Fitchburg Line, where yet another choo-choo went bye-bye, forcing commuters to wait for another train to come up and get hitched to their train for the long, even slower ride into Boston.

AsianKerr was onboard the 6:30 train when she tweeted at 6:50:

It's heartwarming how the little choo-choos help each other out. When the 6:33 into Boston belched its last and died in Sharon, the train behind it agreed to help out and push it all the way into Boston. Good train, good! Of course, that does mean 30-minute delays, but at least Providence Line riders get to have a nice warm feeling, unlike their counterparts on the Newburyport/Rockport line, facing lengthy delays due to boring signal problems, and riders on the Fitchburg Line, facing long delays because, well, it's the Fitchburg Line.

MBTA Transit Police report an outbound train derailed a bit in Belmont Center. MBTA and Belmont Police helped passengers off the train and back to the station to await buses to take them the rest of the way. "NO INJURIES," Transit Police tweeted.

Channel 25 reports T officials called the wheel slipping off the track "a relatively minor incident."

CommonWealth reports on plans to begin shipping 3.9 million gallons a week of ethanol into Revere, on trains that will lumber down the Fitchburg commuter-rail line into Charlestown, where they will switch to the Newburyport/Rockport line up to a "blending terminal" to be mixed into the gasoline that is now shipped along the Rose Kennedy Greenway in 18-wheelers.

Madfilkentist chronicles his three-hour, 45-minute ride from Porter to Fitchburg last night - a trip that normally takes an hour and 20 minutes:

The next stop was Waltham. Before we reached it, the train was stopped for an unusually long time. Finally we were told there were mechanical problems that were being looked at. The lights went out for about ten minutes as all power was cut so the mechanic could look under the train. They came back on again, but there was still no motion. Finally we were told that the next train would hook up to ours and push us.

Robert Burgess reports on an impromptu adventure with son Will this morning: A train ride from South Acton to Lincoln and back again:

There are plenty of chores and errands to run, but we want our little sponge to just soak up the experiences of life. Sure, we're sacrificing my full-time salary to help keep the house running, but that needs to be balanced with Will's needs. The train ride was a great rainy Monday success, so I think we'll try it again sometime and maybe go farther. Maybe, as Will would say, we'll go to infinity and beyond.

Channel 5 reports the 18-year-old was hit on the Fitchburg Line near Belmont High School.

Madfilkentist reports that due to some "suspect" track in the Concord area, his evening commute this week has been 30 minutes longer. On the plus side, he adds:

The good news is that in early October the Fitchburg line offers passengers a very scenic view, especially in the area of the Concord River and Walden Pond. ...