On this of all days: Green Line grinds to a halt; dead trolley is at fault

One of the MBTA's newest trolleys suffered some sort of catastrophic failure with that swiveling mechanism in the center of the car near Boylston shortly before 3 p.m., jamming up the line on one of its busiest days of the year - and leaving some passengers on other trolleys trapped for an hour or more as T workers tried to get them and the newly dysfunctional trolley safely out of the tunnels.

It took the T more than 90 minutes to finally get the Type 9 car - one of 24 the T bought from a Spanish trolley maker in anticipation of the opening of the Green Line Extension - out of the way. The oldest of those cars only dates to 2018.

The Green Line's Patriots Day collapse - the T was halting trolleys at Arlington on one side of downtown and North Station on the other - left riders fuming, none more so than the ones who found themselves trapped on other, non-moving trolleys. As one reported:

over an hour plus i was so close to calling 911 getting @bostonpolice to allow all passengers off at Copley this kind of entrapment is WRONG

Yes, it was bad:

There’s a Lord of the Flies scenario brewing down here. The hierarchy is being established and someone just blew on a conch shell…. This is devolving rapidly…

When the T responded to one increasingly upset rider that crews were working as fast as they could to get people unpacked, another passenger responded to that:

Where??? Because I’m currently stuck in the train at copley and all we hear is “well he moving soon” over and over again for the past hour

No word if among the people trapped down below was Randy Clarke, general manager of the Washington Metro, up here for the race, who much enjoyed his ride on the Orange Line the day before.