Have you inquired into why they became unprofitable? Have you considered the massive government investments into and subsidies for the two other modes of transportation following WW II?

I don't think they were ever profitable. I think they became unbearably more unprofitable after WWII, but I think they were unprofitable before that.

And, when you talk about government investments into the two other modes of transportation, I presume you mean air and highways. You forgot waterways - also created/improved with government investment.

Passenger trains in the US died off in the late 1960s because of automobiles and the Interstate Highway System (don't forget airplanes).