Because otherwise signal problems on the Red Line at Park Street and a disabled trolley on the Green Line at Government Center might mean trouble. Phew. Oh, wait.

NECN reports the MBTA is going to use the Mattapan Line as a guinea pig for a collision-avoidance system that uses radio waves to detect other trolleys and begins to beep insistently if the trolley operator gets too close. If it works, the system could be deployed on the Green Line.

Hah! And some of you people snort at Twitter. Take a look at one chihuahua's feed.

The MBTA is installing 42 phone lines at key employee gathering spots as part of its total ban on employee cell phone use, T General Manager Dan Grabauskas told the Department of Public Utilities today.

Grabauskas said the new phone lines represent one of several steps the T is taking to ensure workers are reachable in an emergency. Grabauskas's comments came at a DPU hearing at which he asked the department to permanently enact the emergency ban put into effect after that May Green Line crash caused by a texting trolley driver.

In addition to the new phone lines, the T has a 24-hour emergency hotline family members can call if they need to get in touch with a T worker. Grabauskas said this has been used 100 times with just one case in which the employee was not reached "in a timely manner." The T now also conducts daily checks of radio equipment on both trains and buses, which he said show the systems work 98% of the time on trains and 95% of the time on buses.

We are committed to putting the necessary systems in place to allay any concerns Operators may have about their families and dependents contacting them in the event of an emergency while they are at work.

Grabauskas's DPU testimony.

David checked the trip planner on mbta.com to see how to get from the North End to Copley. Its primary suggestion: Get on the Green Line and, 20 minutes or so later, get off at Copley. Its proposed alternative: Take commuter rail from North Station to Porter Square, hop on the Red Line for a trip to Broadway (in South Boston), then take the 9 bus:

... I would have thought the orange line from Haymarket to Back Bay station would be a decent second.

Fess up. The riders, however, realize this is Monday.

Also, South Shore commuter lines are on 10-15 minute delays due to what the T describes as "a track problem."

In 1978 and 1979, students at the Powderhouse Community School in Somerville made 249 special tiles that were placed around the Davis Square station. The Davis Square Tile Project is trying to contact the kids who made them as part of a project to show how the square has changed over the years - and possibly help show how the Green Line extension might change the parts of Somerville it goes through.

Local Spice reports on the guy who not only blared MJ songs on his MP3 player last night, he gave some people free MJ mix CDs he'd made:

Now I just want to see a crowd all wearing Farah Fawcett wigs.

Brandon Merritt reports from a Worcester Line train stuck about 2,000 feet past Yawkey. There's a switching problem of some sort that requires some guy from CSX to come in and fix it - which he finally started doing 90 minutes after the train stopped. Some people are abandoning the train and walking down the tracks because the train crew won't back the train up to the station. The smokers on the train are lighting up. The toilet is disgusting. And the only video he has on his iPhone is a Nick Jr. show.

UPDATE AT 8:37 P.M. Merritt tweets his train, the 6:35 local, has started to move, slowly - as has the 6:15 express in front of his train.