Sounds like you had a really great trip, Tom, on the Empire Builder from Chicago to Portland, and then on down on the Coast Starlight. I'm sure plugging in the frequencies, into your scanner, beforehand made it a lot easier and more fun.
I took the Coast Starlight up to Portland, then the Empire Builder from Portland to Whitefish, Mt, this past summer. It was a great trip, except for the fact we were 2-3 hrs late getting into just about every major stop.
I also am a ham operator (WA6ZFM). I purchased a Yaesu VX-5R hand-helf last spring..had a lot of fun with it on the train. I did try a few RR fequencies, but did not hear a thing (I will have to admit I didn't try the RR freq's very often..my main concern was working ham 2 meter repeaters along the way). A friend of mine suggested using an elongated rubber duck antenna instead of the one that comes with the VX-5R. I think it was good advice. I bought a Diamond SRH999 extended HT antenna (around 19 inches long) and it did make a big difference in receive amd makng repeater access. The cost of the thing (around $60) seems a little excessive, however.
Regarding reception distance for RR transmitter towers, there is a "rule of thumb" for 2 meter repeaters which can give you a rough extimate of maximum distance for acceptable receiving. I think it would apply to 160 mHz, as well.
If you take the square of the transmitter height and of the receiver height, add them together, then multiply times 1.4, you can get a rough idea of transmitter receive distance, in miles. For example, if you have 200 ft RR transmitter, the square of 200 is 14.1. Multiplying x 1.4 gives you around 20 miles (assuming you are receiving with a hand-held ..the receiver antenna height can be tossed aside).Again, this is a rough estimate and does not take into consideration transmitter power or antenna gain. If you had a transmitter antenna at 100 ft and you were using a receiver antenna at 9 feet, the max distance would be 10 (sq of 100) + 3 (sq. of 9 ft) = 13 x 1.4 or 19 miles.
There is a chart at:
It figures in transmitter power and gain of the transmitter antenna, as well as the receive antenna, as well as height above ground for both.
Using the chart, at 50 watts and with a RR transmitter at 200 ft, you get about 24 miles range, figuring in no db antenna gain. (This is close to just figuring the square of 200 ft x 1.4). However, when you add antenna gain (you go up 1 line for every db gain) it sure makes a difference. The antennas for 2 meters offered by HRO, for example, seem to range from around 10 db gain up to 18 db gain. If the range for the 200 ft tower is up to 40 miles, it looks to me like you need close at least a 16 db gain, for the RR transmitter antenna, to get a 40 ft range. I wonder what sort of antennas they use? To get to a 45 mile range, it would go up to around 21 db. Do you know if the tower height varies? I am assuming the power output is no more than 100 watts (50 watts in the example). Of course, if the tower is higher than 200 ft the range would be significantly greater.
I guess you could say, in decliing order of importance for receive distance, the most important factors are 1. Height of the transmitter antenna 2. gain of the transmitting antenna 3. power.