Many years ago I saw where the rule of thumb for rail was at least 100 miles. If less than that, truck was supposed to be more economical. IIRC, intermodal was higher like 200-250 mile limit. The last published study I saw said rail intermodal was not cost effective under 500 miles. Good luck getting any general freight quoted at a decent rate unless you're doing a unit train a week or a thousand mile single line haul.

Just look at a map. From San Pedro, Long Beach, Seattle, Tacoma, Oakland, San Diego, etc. a substantial amount of the left coast warehouses including Vegas, Reno/Sparks and the Tri-Cities are within 500 miles of a major (im)port. This is traffic that the railroads and logistics managers have conceded to trucks and publicly supported roads. Until there is a major change in traffic patterns, energy availability or regulations, this is the current reality.