I am a new user of the DCS system having started to set up one week ago. I have three loops of track each utilizing separate DCS outputs. Track 1 and 2 use Fixed outputs, respectively. Track 3 uses Variable/Fixed output 1 (set as Fixed). The outside rails are connected together at the feed points. The trains run as expected … no issues. All three tracks have two short isolated sections for signal control. Track 1 and 2 do not change the signal at either isolated section. The signals remain green. Track 3, however, properly controls the signals, cycling from green to red as the isolated section is entered and changes to red (through yellow on a timer) back to green when the train clears the section. The signals are controlled by relay boxes, one relay per signal. 12 volts A/C powers the relays being converted to DC for the relay coils. This system is several years old and has worked flawlessly for all the signals (conventional mode). I have bench tested the signals and all work properly. The only change this year is the introduction of DCS for train control. I have spent several hours this morning researching this forum and also searching the Internet for clues. I can find many references to isolated rail and signals but none to address this problem. I apologize for the length of this posting but I believe the more info you have, the greater the chance to help with the issue. Thanks for your help.