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Cake day: July 24th, 2023

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  • Laughs in good public transit(rail based is based, but buses are good too), where it can achieve 10~100x the capacity in the same footprint

    With rail, as long as you have a good timetable and a robust signaling system, 27tpdph with multiple service patterns is achievable, and >33tpdph if you run just one service pattern, all while having a top speed of 120km/h and an average speed of >50km/h

    Railway in general (excluding Line-of-sight based light rail and trams) can move stupendous amounts of people at full speed really quickly due to signaling and mass transit inherently being more efficient in general






  • While technically a high speed ‘regional’ metro(like the ones China has been building) does have a top speed of 160km/h, it is more like regional rail than a ‘lowest tier’ urban transit. Most metro systems have a top speed of 80km/h due to station spacing and physics (motor gear ratios tuned for accelaration).

    That or you are talking about the Keisei Skyliner, which is an Airport Express service.





  • royal_starfish@lemmy.worldtoMemes@lemmy.mlEVs
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    1 year ago

    You can use liquified hydrogen which need to be chilled and insulated, and will evaporate away in a short time if not properly sealed

    Or you use compressed hydrogen which means you are basically carrying an IED that weighs several hundred kilograms with the amount of pressure inside the gas tank

    And hydrogen combustion is as others have said, inefficient.

    Another issue is that you also need to use basically pure oxygen if you want to use a hydrogen fuel cell, otherwise the catalyst inside the cell would get poisoned

    And well, there is a car that did all that, the Toyota Mirai, but that also pretty much ended in commercial failure, due to lack of hydrogen filling infrastructure and a whole load of other reasons.





  • It is both, but the pressure one contributes more to lift. You can see this when a wing stalls, the airflow separates from the upper surface and the pressure difference is gone. The angle of a stalled wing still means air is directed downwards, but the overall lift is much smaller.

    At least that is what I’ve been told anyways