I've downloaded a few coasters that seem to have an accelerator in the track.  I'ts not a chain drive but when the cars get to a certain point they are accerlerated.  What are these called and where can I download them.

No download necessary, it is the block brake with its speed set for whatever you want for the coaster at that point (max is 67mph). I frequently use this when I don't want to "waste" park space on a long chain lift section, just do not put it immediately adjacent to the station - have at least one section of track separating them (otherwise the coaster will slowly ...very slowly... leave the station until a certain portion is over the block brake before launching); outside of that you can use them anywhere on any straight section of track except those at an angle.

No download necessary, it is the block brake with its speed set for whatever you want for the coaster at that point (max is 67mph).  I frequently use this when I don't want to "waste" park space on a long chain lift section, just do not put it immediately adjacent to the station - have at least one section of track separating them (otherwise the coaster will slowly ...very slowly... leave the station until a certain portion is over the block brake before launching);  outside of that you can use them anywhere on any straight section of track except those at an angle.

thanks, that's what I needed to know.