No, the best thing is to create it all in a single plan. While plenty of private industry will be brought in to construct it; an overall plan with rules and regulations set for the transportation means is well better than breaking it down in completely different companies. High speed rail isn't something which is highly benefitial going 20 miles. It's benefit really comes in on longer trips. Which is why you want to hook up cities, particularly across State lines. That's the government's business right there.
Thus your appeal to oil is no applicable to high speed rail since the conditions are wildly different.