Here's what a hyperloop will look like. Eventually. Image source: Tesla Motors.

It's been a busy year for fans of Elon Musk's Hyperloop project. In fact, it's been a pretty busy week.

In February, we learned that Elon Musk is revisiting the idea of building a $6 billion, 400-mile, 800-mile-per-hour electromagnetic subway connecting Los Angeles to San Francisco. In partnership with engineering company AECOM (NYSE:ACM), he's building a short Hyperloop test track outside of SpaceX HQ in Hawthorne, California.

One month later, Hyperloop Transportation Technologies (HTT) signed an agreement with the government of Slovakia to "explore building a local Hyperloop system" in Bratislava, again with AECOM doing much of the heavy lifting. There's also the potential that the Slovaks will build intercity Hyperloops to connect their capital city with Vienna, Austria and Budapest, Hungary, and they may even build a cross-country Slovakian system stretching 250 miles to Kosice.

And now, fast-forward a couple more months, and here's what we've learned this week: A third company, formerly named "Hyperloop Technologies" and now going under the moniker "Hyperloop One," is rushing to build its own Hyperloop projects with the help of a team of 11 other companies -- AECOM included.

In a rapid-fire series of press releases this week, Hyperloop announced that it has:

  • Formally adopted the name "Hyperloop One" (hereinafter "H1"), which should help to distinguish the company from rival builder HTT.
  • Secured $80 million in financing "toward building the world's first full-scale Hyperloop," attracting a team of investors that include General Electric's venture capital arm, GE Ventures.
  • Begun "privately funded feasibility studies" into the construction of Hyperloops in Finland, Sweden, and Switzerland, as well as the possibility of building Hyperloops connecting to the Ports of Long Beach and Los Angeles. 
  • Conducted an open-air test of Hyperloop's propulsion system in the Nevada desert, accelerating a prototype Hyperloop "sled" to 116 mph in 1.1 seconds. 

Blink and you'll miss it: H1's Hyperloop "sled" races down the test track. Image source: Hyperloop One.

Pause for applause

Clearly, Hyperloop One enjoyed a banner week and deserves praise for its achievements. In fact, praise was immediately forthcoming. Elon Musk, father of the Hyperloop concept, tweeted: "Full credit to the team that's doing this. All happening without any help from me."

But our question is: What does all of this mean to investors? Venture capitalists are starting to invest in Hyperloop, sure. But how can we invest in Hyperloop?

The first announcement of the Hyperloop concept back in 2013 came by way of Elon Musk's Tesla Motors (NASDAQ:TSLA) electric car company. But while Tesla is a publicly traded company (albeit unprofitable) and has a stock you can buy, both Tesla and Elon Musk have expressly disclaimed any involvement in H1's Hyperloop project.

That said, if you've been reading carefully so far, you'll surely have noticed one other publicly traded company that is involved. One name that keeps popping up again and again, wherever a story involving "Hyperloops" surfaces: AECOM.

How to invest in Hyperloop?

AECOM is helping H1 build Hyperloops in the desert. AECOM is helping HTT offer Hyperloops to Slovakia. AECOM is even helping Elon Musk build his own Hyperloop test track back home at SpaceX HQ.

What do we know about AECOM? Well, when last we checked in on the engineering giant, we noted that the company was not "profitable," having ended fiscal 2015 with a loss. That's no longer the case.

As data from S&P Global Market Intelligence confirm, while unprofitable last year, AECOM earned a $21.4 million profit through the first six months of this fiscal year 2016. AECOM is also free cash flow positive, having generated $160 million in cash profits so far this year, and $578 million in free cash flow over the past 12 months. Valued on that basis, the company's $5 billion market capitalization gives AECOM a price-to-free cash flow ratio of 8.7. The company is projected to grow earnings at 9.2% over the next five years, giving it a price-to-free cash flow-to-growth ratio of less than 1.0.

Is that cheap enough to buy? It depends. AECOM does carry a pretty heavy debt load -- about $3.5 billion net of cash. On the other hand, though, H1 says it plans to build and demonstrate "a full-scale [Hyperloop] system later this year." That suggests there could be chunk of work, and a big cash infusion, coming AECOM's way in the very near future. And if the actual construction projects in Finland, Sweden, Switzerland, and California materialize, then business could boom even bigger.

Even if you're not convinced that AECOM stock is quite cheap enough to buy today, if you're interested in investing in Hyperloop, this is clearly a stock to watch. Unless and until Tesla makes a move itself to get into the Hyperloop business, there's no other publicly traded company on Earth that has its fortunes more closely tied to Hyperloop than AECOM.

H1's prototype Hyperloop "sled" test bed. Image source: Hyperloop One.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.