I heard on the news a few days ago that the Metropolitan Transit Authority in Houston, TX voted to spend 1.4 Billion expanding it’s light rail system. I really haven’t figured out what to think other than it sure sounds like a lucrative business to be in. That is reportedly $73 million per mile. And apparently it doesn’t even cover all of the road “improvements”, but does include $118 million for new light rail cars.
I have always advocated for a place for other forms of public transport beside PRT. As I have written, most forms of transportation rely on fully or partially aggregated groups of people. A light rail system requires a fairly large group of people at each station to be efficient. This begs the question, “How did the people get to the station in the first place?” or rather “How COULD or SHOULD they get together to board this train?” I think PRT competes with buses more than light rail, because buses, rather inefficiently, stop for individual riders as well as groups.
But this kind of price tag gives me second thoughts. I wonder, for example, why don’t they just create a special road or lane and just run a fleet of buses instead of having them on a rail? (I confess I don’t know if Houston’s light rail is electric or what) How much does a bus cost? How many does $118 million buy?
It’s not that PRT CAN’T compete in the densely populated areas. (I would refer the reader to the “MISTER” system for what I consider the most efficient larger station design) It’s just that light rail really can’t compete in the one-passenger-at-a-time world.
Using a previously posted rail design I recently figured out the cost of steel per mile. (This was a VERY rough estimate) I came up with a between 1 and 3 million dollars per mile (depending on station frequency and support design) Of course this doesn’t include labor, and I’ll do all of this in some future post, but I just thought I’d mention it, being on the theme of money and all…And speaking of money…
I Googled (news) the term “cost of burying electrical lines” and came up with repeated estimates of $1 million per mile. This has been a much talked about issue after the recent massive power outages due to Hurricane Ike and the recent ice storms in the Midwest. Anyway, I’ll get back to the concepts of PRT control soon, but I just thought I’d post this stuff so I’m not the only one left scratching my head…
Monday, March 9, 2009
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4 comments:
Buses in their own lane is what BRT, or Bus Rapid Transit, is. Worth a google. Many TODers are in favor of that wherever light rail is prohibited by cost or other factors. BRT is generally more of an express-type service than standard urban buses, but PRT is probably still better for travel time.
While you're looking up cost per mile, can you get figures for electrification too? Third rail electrification I guess is the most appropriate as an estimate for PRT.
Two reasons why light rail has high costs are 1. Having to relocate underground utilities in older parts of the city and 2. Having to also pay for Park n Rides, art work to dress up stations, and other nonessentials.
Since heavy electrical wiring for PRT power is expensive and fairly heavy it would be best to let the local electrical company handle the power distrobution and only tap into where needed like an intersection of two lines. If we assume the PRT system uses a common voltage like 220 volts AC we could have a meter with a circuit breaker box & 4 60 amp circuit breakers near a vertical PRT support. The first two wire lengths would go to the top of the support where one could connect to a 1 mile segment from this intersection to the next one while the 2nd wire proceeded on the track to the other side of the intersection where it connected to the next 1 mile segment. The 3rd & 4th lines would go from the vertical support and follow the turning connector to the 2nd line where they would also connect to the two segments. This would need about 300 feet of wire to power 4 miles of guideway. A 25 mile starter line covering 12 sq miles would need 11 to 13 metered locations which would be much cheaper than installing cable to various parts of the system.
Two responses:
1) I would say PRT most directly competes with light rail than buses because they use very similar resources. They generally require devoted rights of way and usually require building the route from scratch. Bus lines usually just require more buses, not more infrastructure.
2) The cost of running power lines is a good argument in favor of keeping the power source (i.e. batteries) onboard the pod car. If the car powers itself then it's cheaper to build the tracks, there is no one point of failure, and its easier to run tracks out to places that aren't on the power grid.
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