Digital Decoder for C-Track turnouts. You need this decoder to start controlling your turnouts digitally. 

This decoder can be retrofitted to all C Track turnouts with an electric mechanism. Electrical connections are made with plug contacts. An address of 1 to 256 can be set with coding switches. A digital decoder can be installed along with the electric mechanism for turnouts or can be installed later. The decoder is easily connected to the turnout mechanism with plug contacts and can be given its own address (addresses 1 to 256). Tools are special knowledge are not required for this installation. The digital power supply can be taken directly from the power present in the turnout for operating trains. This gives you a finished digital turnout that is also immediately ready to use on temporary layouts.
 

Tip: The 24630 three-way turnout uses 2 of the no. 74490 electric mechanism, and a 6083 / 60830 digital decoder, or another brands K-83 style digital switch installed outside of this turnout must be used to convert it to digital operation.
 

Charlie's Tip: Also check the conversion set 74445, which includes motor, decoder and turnout lantern. We also have some more information here.