Hope this thread helps to give some confidence. I was scared to death when I saw weathering on freight cars and locomotives (I'm still getting over locomotives). When you drop a hunk of change on a piece of rolling stock, it looks great, and making it look like it's been out there (realistically) is one of those "mountains of fear" we have to climb in order to get to the next level of modeling!
We live in a world where we sometimes think we have to pay someone else for things, when we can do stuff in our own. This is the most forgiving method of weathering I found, and an even easier way is to use washes, which I neglected to mention I also used on the Western Maryland flatcar in the thread.
In response to Daryl- I found the chalks in an art supply store. They are NOT oil based. I'll give you the info from off the box: (you'll like the address)
Weber Costello marketing under the name Alpha Color. This product is the Square Pastels Earth Tones. Non-Toxic
The company shows two towns of origin: Troy, Missouri, & Mississauga ON.
Any questions, please don't hesitate to ask!!