It depends on your location and what you're trying to monitor. Looking at a CSX timetable, it appears that you're somewhere west of Rochester. As I recall from a couple of trips through that area on the Lake Shore Limited, the area is fairly flat and an antenna mounted on your roof via a tripod should be more than sufficient.
Remember that most FM signals are "line of sight" and 50 miles is probably at the outside limit of what you're going to be able to receive. Train radios are lower powered, thus the transmission range is going to be much shorter.
I'm assuming that your main monitoring target is CSX (ex-NYC) and Amtrak. If that is wrong, let me know what you are trying to monitor and also a little about the geographic area.
Art Audley, AA3RT
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