How would the govt. make infrastructure improvements like high speed trains if it couldn't use eminent domain, though? It's an intractable problem to negotiate

How would the govt. make infrastructure improvements like high speed trains if it couldn't use eminent domain, though? It's an intractable problem to negotiate with everyone along a path simultaneously, and if they hit a block of people unwilling to sell, and the train couldn't be made to turn fast enough to avoid it at speed, you'd either have a very slow train, or they'd have to waste another x months negotiating a different path. We trade absolute liberty for pragmatism.