Damn, I must have ridden those very train carriages thousands of times! The crash happened just four stops up the commuter train line from where I live. My wife and I went there this morning with our camera. Details here.
Update 21 January: On the basis of first reports and information from a former railway employee, I thought this was an ostentatious suicide attempt. Now there are indications that it was a horrific accident caused by the unsanctioned habits of train drivers. Apparently they routinely jury-rig the safety apparatus for convenience, and in cold weather, to keep the brakes from freezing stuck. This works fine as long as only trained drivers come near the controls. But the cleaning ladies don't receive any driver's training, and they too have to enter the cramped cockpit.
I guess that answers the question:"Do you need an ignition key to start a train engine?".
My son pointed immediately to the relevant Thomas the tank engine chapter.
I had intended to post a link about the crash under the heading "Weird Stuff Stockholmers Do For Fun" but I decided it would be below the belt. Did that cleaning lady by any chance watch a Mad Max or Jason Bourne film before the event?