Certainly 30% is a big impact if it's your day job, but it's unlikely that the transportation infrastructure of the US would be dramatically different. (After all, gas prices had $2/gallon fluctuations that persisted over many years without much impact.) Also worth pointing out that the OP article lists labor as 75% of the cost (which is very different than the source I used).

I'd be very glad to see truck taxes/fees adjusted to better match reality. If that means less truck and more trains, all the better. Still, it's not clear to me that trains don't also get implicit subsidies (that are just less discussed because trains don't inspire as much politics), or that the positive externalities of trucks are important, or whatever.