Quote:
Originally Posted by miketoronto
In addition, too much energy is put into LRT while cities leave the rest of their transit system to rot. Without a viable bus system linking all areas together, how is one single rapid transit line, be it LRT or subway, suppose to make a difference in getting people around?
It has got to be an entire transport plan. Not just a single line.
|
You made some excellent points. But each line is built ontop of others. I can't think of any transit systems in the world that weren't built one line at a time.
What's the basic difference between light rail and heavy (metro) rail?
Between light rail and streetcars (trams)? Between heavy (metro) and commuter rail?
The differences are often just the vehicles used and where the tracks are laid.
Commuter rail make use of existing freight railroad corridors, requiring heavy vehicles meeting FRA regulations. None of the other vehicles have to be that heavy, so all others are much lighter. Metro rail requires completely grade separated lines using third rails for power. Streetcars require streets as that is where they usually run.
What makes light rail so popular a choice is its variability of place and use. It can run like commuter rail in the suburbs with stations far apart, it can run in city streets downtown like a streetcar with stations just blocks apart. It can run in elevated guideways, or in deep subways too.
Even commuter rail can run in elevated guideways, in deep subways, or in streets; but because the vehicles are so heavy, they accelerate slowly, and require stations further apart, you will not find commuter rail stations a few blocks apart. Metros are very expensive to build because they requires full grade separation. Metros can't run on city streets because of the third rail.
Streetcars are in general much slower than all other rail transit because they aren't required to go faster than other street traffic, their slower speeds limits the length of the corridors they can run on.
But light rail can do just about everything! As the starter line in any city, they are very popular and safe choice. I agree, experienced cities can make a wise choice picking the proper train for each corridor, but not initially with the first line. The first line built in most cities is along their busiest corridor.
Why most cities select light rail over other rail option:
(1) Light rail is so much cheaper than metro rail to build. Just look how far metro lines in L.A. and Atlanta were built.
(2) Street running in the central business district allows closer station spacing popular with commuters.
(3) In suburban areas running in dedicated lanes in streets or in abandoned railroad corridors are popular choices to minimize costs
(4) Can climb much steeper grades than commuter rail vehicles when necessary and aren't limited to running in freight railroad corridors.
So, I'm not surprise light rail is a popular choice for the first rail corridor in any city. I think several streetcar and commuter rail lines would make a better and cheaper choice for any city. But few cities have the ability to afford thinking in multiple lines initially, they're lucky to afford planning and building just one line at a time....
Denver built one light rail line initially, took advantage and branched off it for a second light rail line. Only after building the first light rail lines was Denver able to pass Fast Tracks that allowed planning and building multiple lines. That's when commuter rail became the better choice for most of the lines, the downtown street running lines had already been built to distribute commuters downtown. I'm not surprised............