Westside engines come up on e bay all the time.Watch some when they come up, don't bid, just watch and try and get a feel for what they are selling for. And as suggested, look up brass dealers with on line catalogs. Prices are all over the place, so take your time. Sometimes you find one with a paint job representing the owners fictional railroad. The collectors don't want them, so sometimes you can get them for a better price. Avoid projects, engines half dissasembled. A few missing key parts like shouldered screws or gears or side rods, and its a parts source for your next engine. And get beyond sort of soldering. Go to a decent hardware store and buy some brass . Several sheets, tubes, angles. Get solder and flux. And a soldering iron, around 80 watt, not a little pencil iron. Cut out some brass shapes, clean them with emory paper, and solder them together. Make anything or nothing. Practice soldering one piece of brass to another. Its the only way to learn. And what can you ruin? At most ten bucks worth of brass. More than likely you will get some good solder joints, and you're on your way. Now get a bernsomatic propane torch from that same hardware store, and try torch soldering. To build an engine you need to know both, without even mentioning resistance soldering. Practice your skills. Save up your money. Know something about what you want to buy. Learn before you start spending.
brian b