Back in 2006, Tesla CEO, Elon Musk, posted "The Secret Tesla Motors Master Plan (just between you and me)." The first step was to create a "necessarily expensive" low volume car to lead the way. The Roadster achieved that and taught Tesla a lot about the automotive industry, paving the way for step two. Tesla created a medium volume car at a lower price in the form of the Model S, while the Tesla Model 3 is starting to fulfill step 3, which is to create an affordable, high volume car. Step four was to provide solar power, and that mission is now ongoing.

Elektra has reminded us that in 2016, Musk outlined part two of the plan. In terms of vehicles, Musk talked about "heavy-duty trucks and high passenger-density urban transport," and "a future compact SUV and a new kind of pickup truck."

So far we've seen a concept for the Tesla Semi and the Tesla Cybertruck, neither of which look like they will be in production for some time, if at all in the Semi's case. That leaves a "high passenger density urban transport" vehicle still on the to-do list.

Both the heavy-duty truck and urban transport were said to be "in the early stages of development at Tesla and should be ready for unveiling next year," but we saw nothing of the urban transport in the three years since the statement was made. That doesn't mean something isn't coming.

The Boring Company has been quietly going about its business of creating on a new 'Loop' in Las Vegas. It was commissioned by the Las Vegas Convention and Visitors Authority (LVCVA) and should be the perfect home for a form of urban transport.

Electric powered carriages moving around in tunnels isn't a new thing, though, and it'll be curious to see if making those carriages battery powered and rechargeable would give any advantage to a transport system like that. While trains run with all their carriages nearly all of the time, smaller units that can be used on-demand could be more efficient and, in a closed environment, be made fully autonomous.

With that being the last vehicle on Telsa's current plan, we could see something unveiled in the near future. And, without the pressure of needing publicity early, it could actually appear in a completed form.