Re: what kind of walkie-talkie/radio receiver recommended for trainspotting?

Any reasonable quality scanner which covers FM VHF frequencies will work, but as Wade mentions, there are quality differences. Spend a bit more, and you get better sensitivity and selectivity. Better sensitivity (and a better, more tuned antenna) can help with spotty coverage, but VHF frequencies are "line of sight", so in mountainous country, if you don't have a pretty direct line to the source of the signal (whether it's from the repeater site or the train) you won't hear much. On the C&TS coverage is definitely spotty. Selectivity is less important in remote areas, but matters a lot if you're going to use the scanner in more crowded areas for other purposes - see below.

Extended frequency "Ham" transceivers are generally of good quality (though often less so in terms of selectivity outside the Amateur bands), but are probably overkill for non-licensed folks, and there's always that temptation to press the PTT button when you really shouldn't.

I'm a licensed Ham (KG0MR), and have had wide coverage (VHF/UHF) transceivers in my vehicles for years, and I carry a good quality wide coverage handheld transceiver as well, but I have to side with Rich on this one. I just don't find it that useful on the C&TS. The schedule is remarkably regular, and once you know what's gonna be where and when, you're golden. Yes, delays sometimes happen, but...

On the other hand, if you chase the occasional mainline steam (say, 844 or 3985 on the UP) where the schedule is written in jello and you're working blind other than knowing the starting and ending city, a good scanner is invaluable. And as long as you have it, you might as well carry it when you're down on the narrow gauge. :-)

Scott