buses and trains

=cities =transport =trains =vehicles



In theory, I like buses more than trains for moving people.


In practice, trains are generally nicer to use than buses, but they're also much more expensive. So are they nicer because they're more efficient, or just because more money is spent on them?


Trains have tracks that aren't shared by cars and trucks. They get their own tracks because they need them. But tracks are expensive. A 2-lane road is less expensive than a pair of train tracks. A lot of people find this counterintuitive, but you can think of things like this: the purpose of a road is to spread out weight over the ground, and a train has more weight that's concentrated onto a smaller area. But elevated roads need to concentrate their weight onto support pillars, so it's generally better to have elevated tracks and ground-level roads than vice versa.


Trains these days tend to be powered electrically by overhead wires. That means they produce less pollution than buses, and it's more efficient and cheaper to make electricity with gas turbines and use overhead wires than it is to burn oil in piston engines. But buses can also use overhead electric lines, in which case they're called trolleybuses. That works fairly well; the main problem is with intersections, but buses with small batteries can go through intersections without wires in them.


Trains have metal wheels instead of pneumatic tires. That reduces rolling resistance, but that's a relatively small part of the energy used by cars. Metal wheels have much less traction, which means trains can't accelerate or turn or climb hills very well. Metal wheels are also louder than rubber tires. The problem with cars is not that they have pneumatic tires. In fact, pneumatic tires work extremely well. Cars are inefficient because they usually only carry 1 person, because their engines are inefficient, and because they're generally not very aerodynamic compared to planes.


Trains are generally easier to board and exit than buses, because people don't pay for rides while exiting or entering a train. That also means that trains can have more doors, instead of forcing everyone to go through the front. A bus that's almost empty is less fuel-efficient than 2 cars, and a bus that's almost full takes too long to load and unload at stops. Of course, that isn't an issue if buses are free, but it also takes a significant amount of time for buses to stop and re-enter traffic, so full buses need to have fewer stops which means more walking for passengers.


Trains are bigger than buses, so for a given amount of passengers, trains either come less often or are less full. In a lot of cases, I think even buses are too big and vans would be better for public transport. And you also need to compare the cost-effectiveness of that to ride-sharing services like Uber or Lyft. I like that kind of ride-sharing system, but I actually think some anti-monopoly regulation might be needed.


In Europe, train fares are now often more expensive than plane tickets. This is perfectly normal for longer trips. Trains were more used than aircraft in Europe for a long time because of political restrictions on air travel between countries. Similarly, there was a focus on trains over aircraft in Japan after WW2 partly because aircraft were considered more military-related than trains. Japan has put a lot of effort into high-speed trains, but it's actually more energy-efficient to use aircraft than very fast trains because aircraft fly at high altitude where air density is lower, and because being near the ground increases aerodynamic drag. Tracks for high-speed trains also tend to be expensive because they need to be very straight.


On the other hand, trains work quite well for moving lots of heavy things between fixed points. For example, taking coal from mines to power plants, or ore from mines to processing plants. Ships are generally cheaper, and pipelines are generally more expensive to build but cheaper to run, but trains work well for that. China has used a lot of passenger trains and trucks carrying coal, but that's mostly because of the government there being dumb.



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