Recent comments in /f/boston

Anxa t1_j944fmx wrote

It's kind of a "yeah both" situation. Safety barriers would be better. But absent them, it's very much you have to be trying to touch the third rail.

Not directly relevant but I remember one time the red line broke down between central and Kendall, and we had to walk back to central. They had these alarm things set up on the third rail all over the place that presumably would light up if they detected current. None of us went anywhere near it regardless.

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Se7en_speed t1_j943vee wrote

So an actual answer. There are two rails that the train rides on, these are a few feet apart and you can see them if you look down at the tracks. These are just metal and would be safe to touch (if there isn't a train coming). On heavy rail subway lines (not the green line) the train gets power from an energized third rail that is slightly to the outside of these two riding rails. It's also slightly elevated off the ground so that it doesn't short circuit to the ground. That is how you can tell which one is the third rail.

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BACsop t1_j93z6zl wrote

Platform screen doors are pretty much standard on new metro lines in Europe and Asia nowadays, and many cities have retrofitted old lines to add platform screen doors. North America is unique in not moving in this direction--the only project with them on the continent I'm aware of is the new Honolulu automated metro.

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