I am talking about Shinkansen or their French or Chinese analogs. What technological advancement in the recent years allows them to travel so fast? Where I come from most trains don’t go nearly at that fast speed.
In: 2
Normal trains have motors at the front and/or rear, high speed trains have a motor on every car
It’s not just recent years, first Shinkansen line was opened in 1964. What enables bullet trains in general is wider rails, more straight lines and gentler curves.
The bullet train itself has motors on every car, instead of the more standard front and rear car motor arrangement.
The main aspect that allows it is track design.
It isn’t hard to build a train that could go so fast, simply put a very powerful engine into it.
But that isn’t able to safely drive on a normal train track. High speed connections have to be very straight, any curve that is too strong could derail the train. Same for little height differences and so on, it just needs very precise engineering.
In theory we could get even faster with an even more powerful engine, safety remains the limiting factor.
The bullets trains runs on maglev (magnetic levitation) rails which produces very little friction (if any) therefore can travel much quicker. To slow down for stations etc the electromagnets alter the output so friction can slow the trains.
Also, straight lines and as level a track as possible help
Dedicated tracks
High speed trains need tracks with gentler curves and smoother transitions between rails to minimize rattling
They also need to not share their tracks. It doesn’t matter how fast you train can go if it has to spend it’s time waiting on slow passenger trains and cargo trains
This last bit is the problem with Acella in the states. It’s peak speed is a lot higher than the other trains but since it’s stuck behind them all it only shaves like 25% off the overall travel time
Well, the first thing to note is that High Speed Trains are not actually that new – the Shinkansen has been around since the sixties, for example.
As far as the technologies that made fast trains possible in general, though, I would say it was mainly down to improvements in track and catenary technology and the invention of the yaw damper.
In large part, the innovation with the fastest trains is not with the trains themselves, but with the supporting infrastructure. Building track with very wide corners and smooth gradients, ‘superelevation’ (leaning the corners inwards like a motorcycle), and using rails that are continuously welded together in sections more than a thousand feet long rather than much shorter sections joined with fishplates for a smoother ride, to give a few examples. It was also important to develop high tension catenary (overhead wires) and special pantographs that could handle rubbing against those wires at very high speed while conducting power to the locomotives.
It was also important to develop electronics capable of handling high voltage and high current within the confines of a locomotive body. Pretty much all post-steam locomotives drive their wheels with electricity, but for diesel (or older gas turbine, etc) locomotives there’s an on board generator hooked up to the engine. Moving all of that electrical generation outside of the locomotive and only carrying the motors (and some conversion electronics on board) allows more power in the same space and weight. That’s why the fastest diesel trains are only capable of ~145mph while the TGV’s wheeled train speed record is >350mph.
Another important development for the Shinkansen was something called a Yaw Damper. Essentially, train wheels are cone shaped – this is what keeps them on the rails, and allows them to go round corners even with a single fixed axle even though the outer wheel is covering a longer distance. The downside to this is that at high speed, trains have a tendency to rock from side. This is called Hunting Oscillation, and in the best case this can cause a lot of noise and friction as the wheel flanges impact the track while at worst it can cause serious damage to the track and wheels.
The solution to this was a combination of less conical wheels and the invention of the Yaw Damper, a kind of shock absorber used to reduce Hunting Oscillation.
Latest Answers