Thanks Mitch.
I had no idea there was a category called Traditional size.
I searched online and found lots of great Williams 027 FA-2s, but it seems as if they are only sold in pairs, and the ones I looked at only had single motors.
I also looked at Lionel 027 FAs. These don't seem to have the detail of the Williams, but there are lots of them sold separately and they are described as having dual motors. They are also less expensive than the Williams sets.
Both types are engines with only 10 inches or so in length, so they look good to me.
Thanks to all again,
Mannyrock