South Korea Developing 'Near-Supersonic' Train Similar To Hyperloop (huffingtonpost.co.uk)

The South Korean government plans to unveil a high-speed train that can travel at near-supersonic speeds capable of cutting a five hour journey to just 30 minutes. It's reminiscent of the Hyperloop, a proposed mode of passenger and freight transportation that propels a pod-like vehicle through a near-vacuum tube at more than airline speed. Huffington Post UK reports: According to the Korea Railroad Research Institute, it plans to unveil a "hyper tube" format train in the "not too distant" future. Speaking to the South China Morning Post, the government-owned organization said: "We hope to create an ultra-fast train, which will travel inside a state-of-the-art low-pressure tube at lightning speeds, in the not-too-distant future. To that end, we will cooperate with associated institutes as well as Hanyang University to check the viability of various related technologies called the hyper-tube format over the next three years." While this sounds very similar to the low-pressure concept designed initially by Tesla founder Elon Musk it seems as though the KRRI wants to go even further and create a system that will leave Hyperloop looking like a Hornby set. By throwing all their resources at the project, South Korea is hoping to skip past maglev, a still-new propulsion system that uses electromagnets to actually levitate trains above the air. While this removes some of the friction that comes with using conventional wheels, it still doesn't remove the brick wall of friction that is air itself. By building a low-pressure tube however and placing the train inside it you can effectively create a train that could travel at eye-watering speeds.

Comments

Re:Distances

[Solandri]

Keep in mind this is a country with 2.5x the population of New York state squashed into an area about 2/3 the size of New York state. Of countries larger than 10,000 km^2, only Bangladesh, Taiwan, and Lebanon are more densely populated. The highway system is easily overburdened. During the lunar new year, when nearly everyone tries to travel to their home town, it's not unusual for an approx 400 km drive to take 24 hours.

I've traveled between Seoul and Busan by highway, regular train, and airliner. The highway takes way too long when there's traffic. Train is slower than car because of all the stops. Air travel is way too expensive and annoying (flight is 40 minutes, about same as NYC to DC, but takes about 2.5 hours due to time tied up at and getting to the airport). The country badly needs something in-between. They started a high speed rail service, so this is just a natural progression of what they're already building.

Re:Think of why maglev is expensive...

[Rei]

Why are you under the impression that putting it in a tube makes handling turbing forces, stopping forces and control more difficult? Inside a tube, all motion is perfectly constrained, and you have a tremendous amount of surface area to magnetic brake against.

The turning radii issues are of course real, and are highly addressed in the Hyperloop Alpha document. Likewise for dimensional precision. For smoothness, their solution is a radial polisher which drives down the tube behind the pipelaying crew and smoothing out each orbital weld (and the pipe itself). For straightness, alignment is maintained by the same suspension/alignment system they use to deal with earthquakes.

As for why maglev trains are expensive - trains are expensive for a wide variety of reasons. Land acquisition and permitting is often the most expensive. Tunnels and viaducts are often a very large component as well. Maglev technology itself often tends to have high bills.

Hyperloop (as per Hyperloop Alpha, not the student competition) isn't maglev, it's an air bearing system. Skis, basically. The pipe is built the same as oil pipeline, and the budget is similar to that of oil pipeline budgeting per unit area per unit distance (oil pipelines have harder environmental issues to overcome and much higher loadings, more significant temperature management issues, etc, but lower precision / straightness requirements, so it's probably a wash). Tunnel cost is minimized by minimizing tube size (the budgeted tunnels are standard rates for tunneled pipe in non-urban areas). Viaduct costs are minimized by a key design feature of Hyperloop - minimizing peak loadings by having frequent, small vehicle launches rather than infrequent, large vehicle launches. Viaduct costs tend to track their peak loading.

As for land acquisition, the costs in Hyperloop Alpha are kept down by a combination of design and cheating. As per design, it's designed to be small enough to fit elevated into highway medians, with the low peak loadings, making overhead suspension an affordable option. Such places are state land, and already permitted for far more environmentally harmful activity (road traffic). This of course requires state buy-in to the concept, but states often specifically pursue high speed transport options. Private land acquisition is limited to places needed to maximize turning radii, and in-city for stations. The latter is the other place that they cheat - Hyperloop Alpha avoids cities. LA and San Francisco are served by it, according to the design, like airports on the outskirts of town; people have to get connecting legs into town. But that would be an unpopular decision, and you would expect the state to insist on greater accessibility (airports are only out of town because they have to be, not because that's a desirable location). Likewise it bypasses cities en route, unlike HSR. Basically, it's designed as something halfway in-between HSR and air travel (both in terms of service and throughput), but targeting much lower prices, higher speeds, and a lower energy footprint.

In short, it's budget savings vs. HSR are somewhat of a combination of cheating (cutting out a lot of what HSR does) and design (keeping track loadings down, profile small, build in the same manner as an established industry (pipeline), and moving your hardware (capital expense) through the system as quickly as you can.