Weird string encoding problem when inside of Rails but works fine outside of Rails

First off, I'm using Ruby 1.9.2-p0 and Rails 3.0.0. The script I wrote is this:

require 'rubygems'
require 'open-uri'

file = open('http://chicago.craigslist.org/search/apa?query=river+west&srchType=A&minAsk=1100&maxAsk=1600&bedrooms=2&format=rss')
file = file.read.force_encoding('windows-1252').encode('utf-8')
File.open('craigslist.xml', 'w') { |f| f.write(file) }

All it does is fetch an XML feed from Craigslist, encode it and write it to disk. I made it so I could debug some encoding issues I encountered. People occasionally write their postings in Word, then copy and paste it into the new posting form on Craigslist, which results in characters like … (horizontal ellipsis) being inserted into the body or title of a Craigslist post. For example, this one: HUGE 2 Bedroom LOFT in HOT River West! Perfect Price & Amenities…. Craigslist tags their feeds as iso-8859-1, but when I tried to convert from that to utf-8 it didn't work; I either got an error or the wrong characters. Eventually I tried forcing the encoding as windows-1252 before converting to utf-8 and that did the trick. When I run that script, and that posting (which gets re-posted several times a day) is in the latest 25 posts (the number of posts the XML feed returns), I see the ellipsis and everything is great.

However, this morning I did the exact same thing inside of a brand new Rails application, and it doesn't work. I do see the ellipsis, but it's prefixed by another, incorrect character. I pared the code down as much as possible to eliminate any other factors, but for some reason, that code above outside of Rails works fine, but inside of Rails the string is encoded incorrectly.

Unfortunately, I don't know nearly enough about character encoding or Rails internals to figure out what's going on. And I realize using a single post that appears a couple times a day on Craigslist as test data is not ideal, but I don't know how else to get the horizontal ellipsis encoded in windows-1252 in order to more easily reproduce the problem.

If anybody has any idea what might be wrong, or could point me in the right direction, that would be great. Thanks!