tag:blogger.com,1999:blog-7924903188810610343.post8378890599433744950..comments2023-09-21T01:51:15.719-07:00Comments on The Dead Horse Times: Impedance matching and transitEngineerScottyhttp://www.blogger.com/profile/11005863528905991434noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-7924903188810610343.post-67094534412602420902010-07-24T12:04:50.677-07:002010-07-24T12:04:50.677-07:00"All you would have to do is walk across the ..."All you would have to do is walk across the platform". <br /><br />You've described The Netherlands. They have an absolutely fabulous half-hourly service between everywhere and everywhere, centered not on Amsterdam (it's actually rather peripheral though many direct trains not in this timed transfer network have it as an end point) but Utrecht. It's fabulous. Four trains on four routes (normally Rotterdam/Zwolle/Groningen, Maastricht/Amsterdam, Arnhem/Schiphol, and Hengelo/Den Haag) arrive essentially simultaneously and passengers have about four minutes to scramble among them. Then off they go. <br /><br />It happens every fifteen minutes first westbound then eastbound alternately. <br /><br />Superb.<br /><br />Amsterdam is served by direct trains to and from Rotterdam, Den Haag, Hengelo and Groningen that bypass Utrecht on other routes.Anandakoshttps://www.blogger.com/profile/15397105362372268883noreply@blogger.comtag:blogger.com,1999:blog-7924903188810610343.post-78262740877959329412010-07-18T15:43:10.351-07:002010-07-18T15:43:10.351-07:00RA--I thought you might ask. As we both know, bes...RA--I thought you might ask. As we both know, best case performance of LO streetcar is not going to be any better than the bus today. I'll do another post on that soon.<br /><br />As far as the whole impedance/lethargy thing, I probably should emphasize that this particular bit of analysis is a crude model I cooked up to make a point. While real transit planners and system designers do similar things; their analyses are far more complex, and aren't artificially constructed to resemble electric circuit theory. <br /><br />That said, I was attempted to expand the analogy to AC, and model congested corridors as inductors, and transfer stations as capacitors, and service frequency as, well, signal frequency. It works! If there's only one bus or train per day, transfer points block passage; as service frequency increases, transfer points become less and less of a barrier to movement of passengers--and at high frequencies all you would have to do is walk across the platform. Likewise, series capacitors will block DC signals but pass high-frequency ones. Congested corridors have a negative impact on high-frequency service, as bottlenecks form and vehicles bunch up--just like high frequency electrical signals get attenuated when passing through a coil. <br /><br />However much "nerd chic" such an analysis would have generated--it was far beyond what was necessary to prove the point I wanted to make. Hence, it is left as an exercise for the reader.<br /><br />Now what would be the transit equivalent of an op amp?EngineerScottyhttps://www.blogger.com/profile/11005863528905991434noreply@blogger.comtag:blogger.com,1999:blog-7924903188810610343.post-63153373467755482572010-07-18T13:08:11.181-07:002010-07-18T13:08:11.181-07:00Thanks for the refresher on impedence. It's b...Thanks for the refresher on impedence. It's been a while. <br /><br />For comparison, what would L be for the current bus between Lake Oswego and PSU. The fastest weekday run is the 5:03 (LOTC) northbound at 17 minutes and the slowest the 5:19 (4th & Harrison) at 31 minutes. Current estimates for streetcar are for between 30 and 34 minutes depending on alignment decisions.R A Fontesnoreply@blogger.com