RMC?

[TheDialupNinja]

I saw a post of a person who made a rmc coaster. i can't seem to find it in game. any help?

[X7123M3-256]

If you are talking about the custom RMC track type, that is done with a modified version of the game and will not work with the official version. The source code for that is available here.

Lots of people build RMCs by either layering steel track (typically twister or LIM coaster track) on top of wooden coaster track using zero clearance, or building wooden supports underneath with scenery. You can look at the recent Deurklink contest for examples of RMCs built in OpenRCT2.