Sounds right
Video card is too slow for trainz. Sorry!
Yes, that sounds about right if the case is that built-in routes are slow, they normally run okay. You may be able just to upgrade the card without buying a new machine so ask about that first. A card with its own RAM is practically essential. Depending on how much RAM your PC has, that could also be possibly increased.
You could go to Trainz Preferences and reduce Detail level, both Draw Distances and put in
FULL Daytime Fog, that will help a lot.
I have a high end PC and it is the case that the more content put into a route the greater the effect of frame rate and even my PC will jerk sometimes because I overdo the scenery. To make and run highly detailed and realistic looking routes requires an extremely good machine. How well of are you? Ha ha..
Another option you could go for is to shut all possible background programs down
before starting
Trainz by using a utility like
EndItAll. With everything except vital progs going you will find a big difference.
To see frame rates you need the program called
FRAPS and once installed and after using EndItAll go into Explore and start FRAPS up. Set it to show on screen and just diminish it to the lower Control Bar (do not shut it down) so that when Trainz is running the FR counter will be displayed and that will show you without any doubt how well your PC is handling the graphics. You need at least a rate of 12, more if possible.
But to cheer you up a bit I think that practically everybody suffers from a jerk on the screen now and then, it's a thing we all have to learn to live with.
Angela