I know RCT3 isn't on GOG, but it's hard to find anywhere to get help with this game now, so I thought I'd try here.
I am on the 2nd scenario of RCT3, the mine themed park. I made a small adjustment to the existing coaster to make the station longer to accommodate 2 trains. Now for some reason the excitement, intensity and nausea ratings keep dropping down to near zero after opening the ride for a few minutes. I test it again and it comes out normal, then re-open it and it eventually drops again to near zero. What is going on here?

Can't help you with your problem (haven't played the game in years) but RCT3 is on GOG.com: https://secure.gog.com/gamecard/rollercoaster_tycoon_3