Farewell, Porter commuter rail signals

If you stood on the commuter rail platform at Porter Square and looked towards Boston, there has always been a pair of signals, one for each track. They were replaced around 2015 as part of the general Fitchburg Line upgrade project, at the same time the line was double-tracked through Acton and Littleton: they moved east behind the car wash, and with a block signal near Union Square removed, became a distant signal for Swift Interlocking at the McGrath Highway overpass.

Those signals got removed this week as part of the T's Positive Train Control project.

There's very established technology to tell a train what the next signal will be by sending signals through the rails, and displaying the corresponding signal in the operator's cab.  Of note, Amtrak's Northeast Corridor uses a variation on this system that displays both a signal and a speed limit, and so MBTA trains that operate on the Providence Line are already equipped with the ACSES hardware.  In the wake of the 2008 Metrolink crash, Congress mandated that all passenger trains be equipped with a positive train control system that can stop a train before it passes a red signal, and in turn this has caused the T to install cab signaling everywhere on the commuter rail system.

If the train already has a display in the cab telling it what the next signal should be and how fast it should go, you don't also need signals next to the track displaying the same thing.  So the wayside automatic signals are also disappearing across the MBTA commuter rail network.  The Old Colony lines never had them; if you drive on the Pike next to the Worcester Line, you'll also notice the signals there have been removed.

Still, I have a fondness for seeing these signals as I go past.  This is one of a couple of locations where I said "...so what does yellow-over-green mean?" and actually looked it up.  As my...well, "home signal" is a technical term, but you get the idea...I'll miss seeing them.