Hyperloop is a form a transportation imagined by Elon Musk and now being pursued by a couple companies and several governments.

It would use a linear electric motor to accelerate and decelerate an electromagnetically levitated pod through a low-pressure tube at speeds up 1,000 kilometers per hour. Estimates say a capsule could go from Los Angeles to San Francisco in an hour.

So how are we doing on building that?

Here are five things to know about Hyperloop:

1. There are two main companies trying to develop a Hyperloop. Hyperloop Transportation Technologies is based in Playa Vista, California and is building a test track in Quay Valley California. Hyperloop One is based in Los Angeles, but is building its test track north of Las Vegas, Nevada.

2. Hyperloop Transport Technologies is crowdsourcing part of the development. It has 30 salaried employees and then 800 collaborators working part time in exchange for things like stock options. Its part-timers come from places like SpaceX, NASA, and Boeing.

3. Hyperloop One was the first to demonstrate its tech in May 2016. The company has a full system test track and a goal to deliver a fully operational system by 2020.

4. Hyperloop Transport Technologies announced an agreement with the Slovakian government in January 2017, and promises a prototype system there or in California by the end of 2017.

5. Hyperloop One is holding a contest, the Hyperloop One Global Challenge, to develop new route locations and has a feasibility study agreement for a route between Dubai and Abu Dhabi.

So there you go. A smattering of actual technology and the big promise that one day you’ll get into something that looks like a big pneumatic tube and whisk yourself around the world in hours.

Sounds loopy doesn’t it? For more about Hyperloop, check out these articles from TechRepublic: