For nostalgias's sake, I saw some interesting threads on alt.urban.transport about the old Providence subway trolley that I thought I'd reproduce here for posterity.
 

From: Derek J. Hallam
Newsgroups: misc.transport.urban-transit
Sent: Saturday, February 06, 1999 7:05 AM
 

There are two tunnels that go under Providence's East Side.. One, I know a little about, It was built in 1912, and was Rhode Island's "Subway" (Streetcar tunnel to get up college hill) and is now used by Buses. The other, I stumbled across while walking down Benefit Street, slightly north of Angell street. The portal was very large, probably big enough to fit a full sized train through, although it was covered by iron sheeting, with only a small opening about the size of a door. I peeked my head through, and there were rails in it. I wandered the East Side for about a week until I finally found the other portal, It was in the Fox Point section of Providence, over by a sport complex. There was water pouring out of it (There had been alot of rain that week) so I didn't peek in. Instead, I followed the ROW that was grown over, and it took me right to the Railroad Bridge that spans the Seekonk river (Its now raised, impassable.)
    What I would like to know is if anyone knows more about this tunnel, Year of building, purpose, years used, any other enterences, Why it was abandoned, and where that ROW goes (I'm assuming Fall River, Massachusetts)..

To which Dave Snowden of Redondo Beach, CA replied:

 Until the tracks at the old Union Station were removed, the "East Side Tunnel" was used by freights of the Providence & Worcester RR. The tunnel was originally double-tracked and lead off of track 4. Before 1940 there was an electric trolley line that ran from Union
Station through the tunnel to Warren where one line ran to Bristol and the other branch split to Fall River running over an upper level of the Slade's Ferry Bridge.

Also, on the East Side after crossing the bridge there were 2 lines to the north, one connected to the Northeast Corridor at Boston Switch, near Attleboro and the other connected with the Worcester line near Central Falls.

All passenger trains to Boston ran via Pawtucket and were not routed through the tunnel, although the route could have been used by a diesel train in an emergency. I do not know how freights made it through the tunnel during the steam era. The New Haven ran "Race Trains" to Narragansett Park from Boston. I  think there was a train from Providence and it would have been routed through the tunnel, then over the bridge to the track which was in Pawtucket.
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For some reason, the closed-off tunnel (including the whole ROW under
the Hill, and the permanently-raised drawbridge, and a bunch of
abandoned track across the river) appear on my Arrow '93 street map.
Of course said map also has a bunch of other not-quite-current stuff
in that area as well.

dan

--
Daniel Macks
dmacks@a.chem.upenn.edu

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To which Derek J. Hallam  replied:

My Father, who Worked at the old  Supervalu warehouse in EP (now closed) Which was right along the tracks on the East Providence side of the river, said to me just last night that every week or so, a 4 car long freight train would go right through the Warehouse and it would need to be un-loaded inside the Warehouse, then it would continue on towards Pawtucket. So apparently, the trackage around there is still used for freight deliverys to the industrial areas along the Seekonk River.