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| Re: The Return Of ''Rapid'' Transit ? (1500082) | |||
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Re: The Return Of ''Rapid'' Transit ? |
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Posted by Michael549 on Tue Jan 15 15:57:25 2019, in response to Re: The Return Of ''Rapid'' Transit ?, posted by Stephen Bauman on Tue Jan 15 05:47:55 2019. Let me re-phrase myself by using the paragraphs that you have typed:The analog system that I was referring to: "Block systems, being older, tend to be implemented by hard wired relay logic." Re-phrased text - The signal system of the 1920-1930's & 1940's was a kind of analog computer with track detection elements serving as a kind of input sensors, the home signals and stands as a kind of output, and switch machines and related diagram board serving as a kind a "command control center" aka keyboard & output screen. This analog system has several (or many) features built into it - opposing tracks can not be switched onto the same track, trains can be kept at certain distances, switches can not move while a train is moving over the switch, etc. --- Please note that I used the phrase, "current signal system" because that was the information given out in an MTA video concerning the behind the scenes look at the West 4th Street station complex and the equipment still in use that are many decades old. They explained in the video that sometimes older parts have to be re-wired or cobbled together because getting newer parts is difficult or not being made. --- I do not try to make this stuff up. When I go to the NYC Transit Museum and look at the model board and the track switch machine - that's the image that I have of the "old stuff." (I am not "allowed" into the newer tower rooms. I used to stand outside the tower room at City Hall station staring into the room, so now they have reflective glass. LOL! Ha! Ha!) --- I agree with you about computer components and the nature of change. Just try today to buy a brand new computer with a 3.5 floppy drive! Mike |
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