Tesla CEO Elon Musk continues to find ways for his companies to work together. The latest is a plan to use The Boring Company to dig tunnels for transporting Tesla parts and vehicles between facilities.

On Tesla’s earnings call, Musk gave an example of the problem he hopes to solve:

“We are looking at building tunnels, using The Boring Company’s thing, because we have, for example, our seats production is at a separate building on Page. And we have a bunch of trucks moving seats back and forth between both the primary Fremont production and the seat factory. And we actually get constrained on how many trucks can we dock and undock at the seat factory, which is only, I don’t know, half a mile or a mile away from the vehicle plant. So it’ll be pretty easy to just have a tunnel, do an automated conveyance from seats to the factory,” Musk said.

Tesla would be looking to build a tunnel between its 901 Page Ave. seat factory in Fremont to the main Tesla Factory roughly 3 miles away by car at 45500 Fremont Blvd.

CTO JB Straubel said on the call that streamlining this part of the manufacturing process is important as the company begins to deploy high-density and high-velocity lines. When Model 3 production reaches the pace Tesla has planned, production would be dependent on the efficiency of trucks going to and from each factory.