Hi Mick,
As a veteran Trainz Forums user you should know that 24 hours is not a long time to wait for a reply. Crikey, I've sometimes waited weeks.
Okay, Fraps does give the best video results, but like any video capture program it just saves a series of (very large) screenshots to your computer's hard disk at the rate of 25+- a second. If you're using full screen mode to run Trainz along with a high resolution monitor and minimal memory, each screenshot can take a while to be saved, thus causing severe flickering on playback.
If you think about all of the above, it takes a pretty powerful computer with heaps of memory just to run Trainz properly. Add to this, a program (FRAPS) that also needs heaps of memory to work properly, you really are fighting an uphill battle.
Here's a couple of things you can try, followed by what I did to get reasonable results:
Reduce your monitor resolution to 800 x 600 or even 640 x 680. The lower the resolution, the smaller each screenshot will be in kilobytes or megabytes.
Only record part of the screen if FRAPS allows this. I use CamStudio and it certainly allows me to do this.
When making videos I actually run Trainz in Windows mode with a resolution of 640 x 680. I then use the "Part Screen" capture in CamStudio to make the window even smaller. Even with a dual core processor, 2 gig of ram, a super fast video card with stacks of memory, plus a SATA hard disk, the results are less than perfect.
I've been thinking about writing a tutorial on this, but I've been on the road for several months working out of Internet cafes and from a NetBook using mobile Internet. I can't do anything until I get home and get in front of decent equipment.