Rep. Alexandria Ocasio-Cortez published an outline of her "Green New Deal" on Thursday, an ambitious plan to turn the US carbon-neutral in 10 years. One element of her proposal is the use of high-speed rail in the US.

China has the largest high-speed railway in the world, with 15,500 miles of track and most major cities covered by the network.

In May, I took China's fastest "G" train from Beijing to the northwestern city of Xi'an, which cuts an 11-hour journey — roughly the distance between New York and Chicago — to 4.5 hours.

I found the experience delightful, with relatively cheap tickets, painless security, comfortable seats, air-conditioned cabins, and plenty of legroom.

It left me thinking about how far behind US infrastructure has become, when most comparable journeys still require expensive and tiring air travel.

On Thursday, Rep. Alexandria Ocasio-Cortez published an outline of her Green New Deal, an ambitious plan to tackle climate change and turn the US carbon-neutral in 10 years. One element of her proposal is overhauling the public transportation systems to limit pollution, including the use of high-speed rail in the US.

To get an idea of what high-speed rail can mean for a country, we may want to look to China.

Traveling to China can often feel like visiting the future. The cities stretch out for what seems like forever, while new skyscrapers, bridges, and futuristically designed landmarks spring up every year.

Nowhere is this feeling more apparent than when you encounter China's high-speed railway network. At 15,500 miles, the country's "bullet train" is the world's largest.

And it's getting larger.

The China Railway Corp., the country's government-owned train operator, is getting close to finishing the Guangzhou-Shenzhen-Hong Kong Express Rail Link, a high-speed rail line spanning more than 80 miles. And the country's plan is to create an extended network that covers 24,000 miles and connects all cities with a population greater than 500,000.

Currently, there are over 100 cities in China with a population greater than 1 million, a figure projected to grow to 221 cities by 2025.

The practical result of this is that you can pretty much travel in anywhere in China via high-speed rail. It's usually comparable in speed to air travel (once you factor in security lines and check-in) and far more convenient, as I found on a trip to China.

In May, I had made plans to travel from Beijing to Xi'an, the capital of northwestern Shaanxi province and the imperial capital of China for centuries.

The distance between the two cities is around 746 miles, making it slightly more than two hours by plane, 11 hours by car, and anywhere between 11.5 hours and 17.5 hours on a regular train.

On China's top-of-the-line "bullet train," the journey takes 4.5 hours.

If I wanted to travel a comparable distance in the US by train — at 712 miles, New York to Chicago is the closest — it would take 22 hours, with a transfer in Washington, DC. And that's with traveling on Amtrak's Acela Express, currently the fastest train in the US with a speed up to 214 km/h (150 mph).

Traveling on one of China's fastest bullet trains is an entirely different experience: