[Mpls] Transit Modes

[A.J.Colianni]

On Jan 8, 2005, at 9:49 AM, Steve Nelson wrote:
>
> PLEASE PEOPLE START DOING YOUR HOMEWORK BEFORE YOU SPOUT OFF ON A 
> SUBJECT YOU HAVE OBVIOUSLY NOT RESEARCHED.

It's hard to do homework on a subject that is near-fantasy-land and 
when it's proponents get crazy whenever someone questions something!

Steve Nelson mentioned earlier the Target Center and loading a 
theoretical 18,000 passengers into LRT vs. PRT:

Steve Nelson wrote:
> Really?  Picture a crowded event at Target Center coming to a close.  
> A group of seniors from Horn Towers has attended and plans to return 
> home. These patrons can choose to cross the street and go down the 
> block to catch LRT which, theoretically, runs 8 - 9 minutes apart and 
> can haul 190 fully loaded.  Of course they also get to stop at every 
> stop along the way and make their wait for their bus connections on 
> Lake Street.
>
> Or they can go to the attached station at the Target Center where a 
> continuous stream for 4 passenger PRT cars are moving through the 
> station. No waiting.  As the patrons leaves the station paralleling 
> the LRT they do not have to stop at the same place as the car in front 
> or the car behind as cars are free to exit at any station without 
> making everyone else go with them.
>
> Assuming part of Dean Zimmermann's model has been built, when the car 
> reaches Lake Street it turns west and continues on to Horn Towers 
> where an attached station allows them to disembark without ever having 
> to set foot outside.
>
> Now if that was a group of 40 people they have used 10 cars.  With 
> cars continuously flowing through the station at Target center and an 
> average loading time of 2 minutes they are all on their way home in 20 
> minutes. Assuming they all stand in line at one gate.  If that station 
> is a 5 gate station and they spread out among the 5 gates then they 
> are all on their way in 4 minutes.
>
> Never having to go outside--non-stop service from 
> door-to-door--capacity equal to or greater than the LRT 
> behemoth------guess there's no efficiency there!

"-capacity equal to or greater than the LRT behemoth------guess there's 
no efficiency there!"

Right...

Some quick math:

LRT:

18,000 people / 180 people per car = 100 cars needed


100 cars / 3 car trains = 33 trains

33 trains * 8 minutes per train to arrive = 264 minutes to move 
everyone from the target center with LRT

PRT:

18,000 / 4 people per car = 4500 cars needed

4500 cars * 2 minutes per car loading time = 9000 minutes to move 
everyone from the target center with PRT

That's nearly 35 times slower. And it's assuming you'd be able to get 4 
people in every car.

Steve also said, well, what if there were 5 loading stations

9000 / 5 = 1800 minutes to move everyone from the target center.

It's still going to take 9 times as long to move everyone from the 
target center.

PRT simply does not scale for the amount of people we need to move 
around this city!

If steve says, well, let's just build 10 stations at the target center. 
9000 / 10 = 900 minutes

I say, let's just make all those 4 car trains! 25 trains * 8 minutes = 
200 minutes

Well, PRT fans? Let the faith-based refutations commence!
--
aj colianni
aj at colianni.net