Eminent domain is proper for any mode of transport operating as a "common carrier" -- public highway, railway, pipeline, electrical transmission lines, etc. E.g., Keystone will transport any shipper's crude oil to any refiner's refinery.
But Keystone isn’t a public agency, it’s an independent company. So that would be the equivalent of a private highway or say a private parking lot. I’m sure if Trump had won and built the parking lot, he would have let anybody park there.