From: feliphil@gmx.net   
      
   > bob brought next idea :   
   > >   
   > > I do wonder the extent to which power independence is useful for a   
   > > tram, though. On a trolleybus, the utility is clear, but if you   
   > > need tracks to run a tram on, the restrictions of being tied to an   
   > > overhead wire are not significant. The only use case I can see for   
   > > them is in locations where the visual intrusion of overhead power   
   > > is undesirable. Robin   
   >    
   > A second possible usage is at crossings between different transit   
   > systems, for example a tram line and a trolleybus line. The needed   
   > insulation between the wires makes such crossings quite complex, and   
   > it is now easier to give the trams some independence from the overhead   
   > wire, so that they can lower the panto before the crossing and raise   
   > it back after. This way, the tram wire can simply be interrupted at   
   > the crossing and the complexity is eliminated.   
      
   Bullshit.   
      
   Overhead crossings are way simpler and more reliable than what you have   
   in "mind".   
       
   > Another case is for passing under short tunnels or bridges, where   
   > there wouldn't be enough free height to install the overhead wire +   
   > required insulation distance. Get the trams under there on their own   
   > power and the problem is solved...   
      
   Same. You would end up with the line blocked for several hours per day   
   per bridge due to a streetcar ripping off its pantograph.   
      
   > Then you have the places where trams are stored and maintained, which   
   > require also complex overhead wire installations, which can totally be   
   > eliminated if the trams can move independently.   
      
   Same. This has been a non-issue for over a century.   
      
   > Also, because of the low floors, the technical equipment on last   
   > generation trams is often on the roofs, which means maintenance shops   
   > must be equipped with platforms from where this roof-mounted equipment   
   > is easily accessible. Such platforms require sophisticated safety   
   > equipment to ensure noone can be on them if the overhead wires are not   
   > switched off and grounded. If the trams can move to those platforms on   
   > their own power, the wires can simply be eliminated.   
      
   "Simply". Bullshit.   
      
   All topics you mentioned are total non-issues. You've obviously never   
   been professionally involved with the engineering and/or operation of   
   electrified rail networks.   
      
   The obscene cost of those "wireless" systems *are* a serious issue,   
   however.   
      
   The "idea" of wireless streetcars was a cerebral flatulance emanating   
   from the "brain" of a lifeform named Alain Juppé, ex-mayor of Bordeaux   
   and convicted felon, who didn't want to have any wires in the air in   
   front of "his" city hall. Alstom agreed to develop such a nonsense   
   because they smelled an opportunity to create single-vendor-lock-in for   
   the rolling stock. Then the whole bullshit unfortunately went viral   
   thanks to the total techno-economic incompetence of political "leaders".   
      
   Sincerely,   
      
   Wolfgang   
      
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