Speaking to Wired, a spokesperson from the Boring Company has explained that the firm plans to build different types of transportation systems in those tunnels. Some will be "standard pressurized tunnels with electric skates going 125+ mph," while others will "use pressurized pods in a depressurized tunnel to allow speeds up to approximately 600+ mph (aka Hyperloop)."
Still, this is the man that was faced with incredulity when he vowed to recycle rocket boosters, then went ahead and made the whole thing look like child’s play. So his decision to build an underground Hyperloop will certainly buoy the nascent industry surrounding the peculiar form of transport, as many people will assume he can make a go of it. Whether he can or not? Keep your eyes on those tunnels.