MBTA Transit Police tweet somebody left a threatening message on a North Station restroom wall this afternoon, but that a search that started just as the evening rush was getting underway found no device and that as a result, "all service resuming normal operations."

The T said today that riders on the Greenbush, Kingston/Plymouth and Middleboro/Lakeville Lines will see real-time arrival info on those platform sign boards tomorrow.

"Displayed in a countdown format on easy-to-read electronic message boards, the information will provide minute-accurate train arrival times to customers waiting for their trains," the T says. The Worcester/Framingham and Lowell lines will get the updates next week, the T says, adding plans are to have all 13 commuter-rail lines operating by February.

The MBTA is also promising special AM broadcasts at stations with the same information, so commuters can stay in their cars until the train is near. The Anderson stop in Woburn will be the first to get the new AM frequency, followed over several weeks by other stations with at least 50 parking spaces.

Meanwhile, the T says that by the end of this summer, it expects to equip all of its 410 coaches with WiFi, making it the first commuter-rail system in the country with full-train wireless.

Meanwhile, the MBTA also said it will begin looking for a new contract for somebody to operate its commuter-rail lines starting in 2013, after granting current operator MBCR a two-year extension.

Council on American-Islamic Relations vs. Massachusetts College of Pharmacy and Health Sciences.

Preston Jackson, a Mattapan man charged with continuing to rob Back Bay, South End and Fenway stores even after his photo started showing up on TV, pleaded guilty today to nine counts of armed robbery and one count each of armed assault with intent to rob and attempted robbery, the Suffolk County District Attorney's office reports.

Suffolk Superior Court Judge Peter Lauriat sentenced Jackson to 13 to 20 years in state prison.

Jackson never actually showed a weapon during his holdups, in which he typically passed a note to a clerk, but was charged with armed robbery because he told his victims he was armed. After his last, failed heist, police recovered a note on the street that read "Give me the money quietly and no one will be shot."