Old LIRR tracks?

I was on the west side of Manhattan, walking towards 44th and 11th.

It was late at night but I realized that we were walking over a set of RR tracks that ran east/west. What are they and are they still used?

So you were walking toward the river on 44th St, and a couple hundred feet west of 10th Ave you crossed above a pair of tracks running parallel to 10th Ave?

That's ex-New York Central freight trackage dating from the early 1930s, now (since 1991) used by Amtrak trains from Penn Station to Albany and beyond.

thanks Tim. Is there a map showing all the traks emanating out of Penn Station as of present day, perhaps online?