Yes with no problems at all!
That would be a wise choice because that Williams
http://www.modeltrainstuff.com/Williams-By-Bachmann-O-S-2-Turbine-6-8-6-PRR-p/wil-40401.htm?CartID=2 is rated for O27 curves. Any track will work and it is a traditional Scale locomotive. Most rolling stock is traditional scale particularly older items. Most Accessories are traditional scale as well.
What transformer do you have? If it has horn and bell buttons you can control those on the Williams as well and you don't have to worry about the radius of the curves.
Lionel is the Leader in O-gauge and every brand that I know of for 3-rail O-gauge will work with a conventional Lionel Transformer and some are compatible with TMCC therefore they will work with Legacy too.
Lionel and others do make Standard O-Gauge, sometimes called full scale (a little bit bigger and more true to scale) but that Is where you begin to run into problems with curves. Generally speaking, bigger equipment needs bigger curves.
What are the curves you are using? Examples are O31, O36, O48, O60, O72, O84. You can look on the back of Lionel FasTrack and it will tell you what it is. O36 is what comes with new Ready to Run sets.
If you have not already ordered your trains I would look into Ready to Run sets. They are a good way to get started in the hobby. They come complete with everything you need to run a train. Transformer, track, locomotive, rolling stock and more in some. They even come with a DVD to help you get started.
Even if you already have some things Ready to Run set are still an economical way of expanding your railroad.
Expansion Packs are another economical way to expand your railroad. They usually have rolling stock, track and accessories.
When you buy equipment find out the rating for curves and don't buy anything that needs bigger curves then the smallest track curve you plan to run it on.
I will find some links for you with more information.
If you want to tell me what you already have I can make some suggestions on what you might like to get.
I see you already found the best place to buy your trains, MB Klein/Model Train Stuff, but don't limit yourself there are good deals everywhere.
Do you have an APO address? Check your supplier to be sure they ship to an APO address a few do not.
Louis
hey can i run a william train with lionel controller