Tesla should ( and will be in the position to ) make the worlds biggest roadgoing EV in a couple years. This EV will have a 3.4 MWh battery pack. Thats 3.4 megawatt hours. It will weigh about 80000 pounds and ( by my back of the napkin calculation ) have a range of at least 2000 miles. Maybe closer to 3000. The great thing about having a range over 2000 miles is that will let it do its job perfectly. It's job? Transporting about 40 Tesla battery packs from the Giga-battery factory to the Tesla car factory. Converting a normal ( but streamlined ) truck to use electric drive, it would haul an undersized ( and very aerodynamic ) trailer that holds all the battery packs. The battery packs are all connected together to provide the traction pack for the truck. The trailer would only be about 30' long, 6' wide and 5' tall, giving it about 1/3 the frontal area of a normal semi trailer. Eliminating the 1500 pounds of diesel fuel and a couple thousand pounds of diesel engine and transmission for a couple hundred pound electric motor will also help make the truck smaller, lighter and more efficient. ( I haven't figured out is how to get the empty trucks back to the battery factory ) I'm not saying Tesla should spend their manpower on this, they should subcontract this out. If they choose to transport the battery packs by rail, they could use a standard diesel locomotive - but bypass the diesel entirely, and run it as an electric locomotive.