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| Re: Pantograph for Trackless Trolley vs. Light Rail or MU (486547) | |||
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Re: Pantograph for Trackless Trolley vs. Light Rail or MU |
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Posted by WillD on Thu Sep 6 11:08:10 2007, in response to Pantograph for Trackless Trolley vs. Light Rail or MU, posted by RonInBayside on Thu Sep 6 09:18:17 2007. There are non-rail vehicles which use pantographs for electric power collection, but the only one I can think of off the top of my head are trolley-assisted off road mining dump trucks.http://hutnyak.com/Trolley/trolleyphotos.html San Fran manages to run trolleybuses and pantograph-equipped LRVs side by side without too much incident. Because the pickup shoes on a trolleybus swivel the wire can be offset from the lane of travel by a considerable distance. Thus you could in theory have trolleybuses and pantograph-equipped LRVs operating on the same transit lane for example, but you'd need three wires for power distribution. I don't see why restringing the wire would be a big deal if you're installing LRV tracks. The street is already going to be ripped up for the installation, so you don't have to maintain trolleybus service on that particular segment and can work on the wire while it's grounded. Also the trolley wire support poles and such are already there, so that's not a big deal. All you'd end up paying for would be the new streetcar wire and the labor to install that and the relocate the trolleybus wire. It's likely impractical for a regular trolleybus to use a pantograph for pickup. The vehicle itself is perfectly able to maneuver out from under the wire, and a fixed LRV-like pantograph would rob it of that ability. Mounting the pan atop the pole as seen in ISR's concept here are also likely a poor idea for the near future as that'd require some sort of logic and control system to recognize the wire, recognize the pole position, and control the pole accordingly. Such a system would likely be fairly prone to failure. That being said I've always wished Seattle would have ordered their DE60LFs with provisions for dual mode operation using 750-1500vdc power picked up from the LRV wire in the downtown tunnel. The DE60LFs, diesel electric parallel hybrids, have permiated the once clean tunnel with the stench of diesel exhaust. By fitting a large pantograph as wide as the body just ahead of the battery enclosure, placing two small, retractable electric return wheels on independent traversers ahead of the center wheel, then modifying the hybrid electric transmission to deal with the higher voltage they could get a fairly simple, lightweight dual mode hybrid bus. Outside the tunnel it'd operate just like any other DE60LF, with the battery, diesel engine, and electric motor working in concert. Once in the tunnel the pantograph would go up, the return wheels would drop down and contact each running rail, and the battery and motor would take their power from the 1500vdc overhead power. In the event they need to pass a broken down vehicle or some other obstruction, the battery could provide some power, and the diesel would be there if absolutely neccesary. |
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