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The grade separation is a strange distinction to make, since trains do not stop for at-grade crossings. Perhaps the distinction you meant to make is between tra

by burfog 9y ago

The grade separation is a strange distinction to make, since trains do not stop for at-grade crossings. Perhaps the distinction you meant to make is between trains that run in city traffic and those that do not. But anyway... I'll pick a couple examples that I have actually used. They are effectively random; I'm not choosing them to make rail look bad. EXAMPLE ONE The commuter rail between Lowell and Boston runs 26 trains on weekdays. This carries 11,965 people a maximum distance of 25.4 miles (40.9 km) within a window of 17.53 hours. Most people don't actually go the full distance. This is a pitiful 498 to 683 people per hour per lane, depending on if you count the nightly shutdown or not. The reality is far worse, since most people don't make the full 25.4 mile trip. Now consider the linear space occupied. On average, there are 19 to 27 people per mile. On average, they are spaced 196 to 269 feet apart. Again though, most people aren't making the whole trip. Normal highway traffic is denser than that and the lanes are narrower too. EXAMPLE TWO The commuter rail between West Palm Beach and Miami runs 50 trains on weekdays. This carries 14,800 people a maximum distance of 70.9 miles (114.1 km) within a window of 16.67 hours. Most people don't actually go the full distance. This is a pitiful 617 to 888 people per hour per lane, depending on if you count the nightly shutdown or not. The reality is far worse, since most people don't make the full 70.9 mile trip. Now consider the linear space occupied. On average, there are 8 to 13 people per mile. On average, they are spaced 421 to 607 feet apart. Again though, most people aren't making the whole trip. Normal highway traffic is denser than that and the lanes are narrower too. CONCLUSION We can fit 2 to 5 times as many humans in that land distance if we use single-occupancy vehicles on a normal highway instead. This would save land for wildlife, housing, or whatever. By switching to a normal highway, average speeds would double. (the train may peak at 80 MPH, but with all those stops it averages less than 40 MPH) The saved time can be put to use for sleeping, earning income, or spending time with family. Now, putting those together with the extra width of a rail line, we're looking at 8 to 20 times as many people moved for a given amount of land. The land wasted by rail is obscene.

eesmith 9y ago
A grade-separated junction, in the context of trains, is discussed in more detail at https://en.wikipedia.org/wiki/Flying_junction https://en.wikipedia.org/wiki/Flying_junction . > A flying junction or flyover is a railway junction at which one or more diverging or converging tracks in a multiple-track route cross other tracks on the route by bridge to avoid conflict with other train movements. A more technical term is "grade-separated junction". A burrowing junction or dive-under occurs where the diverging line passes below the main line. > The alternative to grade separation is a level junction or flat junction, where tracks cross at grade, and conflicting routes must be protected by interlocked signals. The examples you gave are all from the US, which as I mentioned has been designed around cars for almost a century. We (in the US) are a local minimum where it is hard to switch to a mass transit system because we've spent so much time optimizing for cars. That doesn't mean that mass transit systems are inherently less efficient. We have only to look to NYC (to say nothing of other countries) to see numbers far in excess of what you mentioned. So if rayiner's assertion is correct, that the government has an obligation to optimize the limited use of public land - which I disagree with - then I still argue that it means we should be doing a transition to a different way of organizing our cities and towns so they are better optimized for mass transit instead of personal vehicles. Like what The Netherlands started in the 1970s.

by burfog 9y ago

eesmith 9y ago

A grade-separated junction, in the context of trains, is discussed in more detail at https://en.wikipedia.org/wiki/Flying_junction https://en.wikipedia.org/wiki/Flying_junction . > A flying junction or flyover is a railway junction at which one or more diverging or converging tracks in a multiple-track route cross other tracks on the route by bridge to avoid conflict with other train movements. A more technical term is "grade-separated junction". A burrowing junction or dive-under occurs where the diverging line passes below the main line. > The alternative to grade separation is a level junction or flat junction, where tracks cross at grade, and conflicting routes must be protected by interlocked signals. The examples you gave are all from the US, which as I mentioned has been designed around cars for almost a century. We (in the US) are a local minimum where it is hard to switch to a mass transit system because we've spent so much time optimizing for cars. That doesn't mean that mass transit systems are inherently less efficient. We have only to look to NYC (to say nothing of other countries) to see numbers far in excess of what you mentioned. So if rayiner's assertion is correct, that the government has an obligation to optimize the limited use of public land - which I disagree with - then I still argue that it means we should be doing a transition to a different way of organizing our cities and towns so they are better optimized for mass transit instead of personal vehicles. Like what The Netherlands started in the 1970s.