Märklin-C series HO gauge track is designed specifically for AC powered, effectively three-rail Märklin layouts. The C-series track has integral ballast and is slated to replace the older M-series track. It is only compatible with Märklin-M and Märklin-K HO track (all three may be joined using special adapter track sections). The table and image below show the components in the RR-Track Märklin-C HO track library.
Items in red have been recently added to the C library.
The current version of the v5 Märklin-C HO track library is 4.60.006. If yours is earlier, go to our updates page to download the current version.