I just built a coaster with mountains and other custom scenery.  The Trees and buldings all saved but the mountains did not.  I found this to be true when putting in a river or stream as custom scenery in some of my parks.  Why is this so and is there any way around it.

What are the objects you're using for the mountains and rivers? I suppose mountains can be built out of a rock set, but I didn't know there was any scenery that allowed the building of custom waterways.

I built them our of the game itself. Using the terrain changing feature.

Ah, that makes sense. Terrain and water do not qualify as scenery within the game, so they cannot be saved with a track. The only way around it would be if custom scenery existed that perfectly mimicked terrain and water, which it does in RCT2, but might not in RCT3. "Mountains" can be created in RCT3 with certain rock sets, though they'll have more of a Big Thunder Mountain look.

that explains that.  I also had some moats and water in a medival setting that didn't save either.   thanks

Shy Guy's Rock Set works as well. Water sets are hard to find. I've never found a good one.