Amtrak, founded after the collapse of the rail industry (especially the passenger rail industry) in the 1950s and 1960s to continue to provide passenger rail service, has been a major whipping boy for Congressional Republicans pretty much since it was founded.
Freight rail has become profitable again, and if energy prices go up, it should do even better. But passenger rail is still barely ridden in this country, with the exception of the Northeast corridor.
The reason is simple: it's not easy to get people to take the train when it cannot even be competitive in terms of time with the personal automobile, much less with air travel (for limited distances; due to air travel's major overhead and, in many places, major delays), and if you cannot fill the trains, you have also got the problem of costs.
And often, the train is often not even competitive (much less beating) the peronal automobile in terms of travel time.
Below, the mean speed of a train on various tracks throughout the country according to their Amtrak timetables; when lines intersect with the Northeast corridor, I leave the part on the corridor out. When certain parts of a line are far slower, I note that as well. Specifically, I put the mean speed when we discount the time spent waiting at stations (when that time is specified in the schedule), just to point out how bad things are; these are speeds over time when the train is moving (minus I suppose some number of minutes at the brief stops)
I'm ignoring the few lines that go across national lines, because customs slows things down there.
St. Albans, Vermont, to Albany, NY: 40.2
Albany to New York Penn, 56.4.
Rutland, Vermont to Albany, NY 32.4d (15 minute wait in Albany)
Rouses Point, New York to Albany, NY 34.2
Bellingham, WA to Seattle, WA: 38
Seattle, WA to Portland, OR: 53.4
Portland, OR to Eugene, OR: 50.9
Washington, DC to Raleigh, NC: about 53
(having trouble with the rest of the route until Jacksonville, FL along the east coast, but mean speed seem to remain in low-to-mid 50s)
Jacksonville, FL to Tampa, FL: 48.4
Winter Haven, FL to Miami, FL: 47.9
Chicago, IL to Omaha, NE: 58.9
Omaha, NE to Denver, CO: 56.6
Denver, CO to Salt Lake City, UT: 38
Salt Lake City, UT to Emeryville, CA: 49.8
San Jose, CA to Sacramento, CA: 43.1
Washington, DC to Cumberland, MD: 46.3
Cumberland, MD to Pittsburgh, PA: 34.8
Pittsburgh, PA to Cleveland, OH: 48.3
Cleveland, OH to Toledo, OH: 49.8
Toledo, OH to Chicago, IL: 53.4
Washington, DC to Clifton Forge, VA (43.1)
And it goes on like that, basically maxing at the low 50s as a mean speed when moving, except on the incredibly flat, straight Chicago to Omaha stretches and such; also, I believe the Albany to NYC tracks may have had some improvements done.
Except, of course, on the Northeast corridor, where NYC to Washington is 65.9 mph on average, better than a car can do straight without speeding.
I cannot find the distance for the track from NYC to Boston, so I can't provide an estimate there.
The point is, though that even 110 mph max track would be good enough to significantly increase ridership; it worked on the line between Philly and Harrisburg, where the 59.4 mph mean speed on the Keystone route has greatly increased ridership.
It'll work on the other areas as well. And of course, California and to a lesser extent Florida will be revolutionized.
This is why the work being done to get even semi-high train speeds (and genuine high train speeds in Florida and especially California)