(Newer LGB sound locos already include this circuitry.). Up to four 55040s can be used together (eight functions total).
For Gauge G, for LGB 12010, Switch Decoder 1K II (1-Channel) NEW
DRIVE-S 2.0 (2A Locomotive Decoder, Susi, 4 Funktionsausgänge), Steckschuhe LGB
Mxion ZKW DCC 2 Channel Turnout Decoder 3 Way Turnout Mode Compatible with LGB
DRIVE-SB (4A Locomotive Decoder, Susi, 6 Funktionsausgänge for LGB Wismar/
mXion EKW DCC 1-Channel Turnout Decoder + Output VERGOSSEN Compatible LGB EPL
2 Channel Replacement Decoder for LGB Cars (RhB, DB) with Anti-Flicker Buffer