citywatcher wrote:Actually I meant against obahn. The improvements people keep mentioning would already have been built into a rail system which could be extended and only highlight obahns shortcomings. . People alighting at interchanges, higher density , feeder services , the problem of Grenfell st
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Having to spend $160m on a tunnel
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My point is sure the obahn is ok. I just think rail would have been better IN THE LONG RUN. We proposed in this city way back CITY METRO NEAPTR MATS ETC . I just feel we missed an opportunity. I don't want to see obahn dug up. We do have our work cut out now to make it work as well as is needed.
All of the things you mention as specific to the O-Bahn apply to rail as well. Most perceived advantages to rail are bolt-on features. Bolt-on features can be applied to a guided busway, an un-guided busway, or even a non-busway with a distinct route. Continuous off-track running is pretty much the only intrinsic benefit of the O-Bahn over rail. Rail's only real intrinsic benefits are economy through easy availability of rollingstock (popularity), and economy of scale when you need to move a lot of passengers along a linear path. This is where O-Bahn shines over rail on relatively short routes - like the N.E. Suburbs. And hence why rail would not have been better in the long run. The relative short run from the N.E. Suburbs would make transferring to a rail corridor very unattractive. More people would be in their cars and we would be talking about the need for a N.E. Freeway instead of a tunnel through the parklands.
fishinajar wrote:As volume increases, ie. too many buses using the o-bahn and grenfell/currie streets, we will not be able to run all buses the whole way.
Based on what quantification? When the O-Bahn reaches its capacity, it is already near the top of light rail's capacity and time to consider heavy rail.
The only concern is the bottleneck of running back onto street. This can be addressed with more stops along Grenfell Street. The PTB are already looking into this with the plans to make Grenfell a PT only street.
fishinajar wrote:Also not all routes will fill their own buses to capacity, leaving either some buses partly empty (wasted capacity) or people utilise these buses to then transfer or alight to take their car from interchanges (meaning people may not be able to get on their own bus (route).
Not all routes need to run all the way. Not all routes need to run all the way, all the time. The current paradigm is to only run lower patronised routes during those times when they are more patronised. For example; the 556, 557 and 559 buses are run as feeders at all times, except in the morning peak, when the run into the city direct, and the afternoon peak, when they run out of the city direct.
Additionally, an aim (for economy) is to run buses at near capacity as often as possible, but it's not always necessary or possible to do so. The main aim is to encourage people out of their cars during peak periods. So all this talk of capacity only really applies to the 2 or 3 hours at each end of the working day.
fishinajar wrote:Dedicated o-bahn only buses could be multi sectioned with much greater capacity, but could not navigate suburban street networks. They would require a greater turning around area, ie. light sq.
The need for greater capacity vehicles assumes that we have a great quantity of transferring passengers. If we have a great number of transferring passengers, then the system is failing. Remember: transfers incur a 19 minute perceived delay, thus encouraging people to jump in their cars. As soon as you are devising elements of a system for transfers on a short route, you need to ask yourself if you're doing the right thing.
Such higher capacity vehicles are used on the Bogota Busway. Which isn't guided, but operates in dedicated corridors down very straight routes. They work for Bogota, but require specialised infrastructure for loading and unloading as well as the fairly straight routes. This is before considering the engineering challenges of running double bendies on a guided busway.
Exit on the right in the direction of travel.