If you are not familiar with Boolean logic, an alternative is to use Google's "Advanced Search." The link to that is on the search home page, near the top, but only after your first search, or use this link:
[www.google.com]
Using Advanced Search allows you to specify in separate boxes terms to look for and exclude. Once you click the button, it builds the Boolean query for you, and is a neat way to learn how it works.

While perhaps not pertinent to the original question, a neat trick is to limit the Google search to a single domain with the "site" feature. Using this, for instance, as a non-paying Trainorders viewer, you can search just the Trainorders site, even though normally have to pay to use the TO search function. To see how this works, paste this in the Google search box:
"Mainline electricfacation site:trainorders.com"
Yes, there is a misspelling, but thats how the thread title is spelled on TO.