Several months ago I converted a small (34" x 87" shelf layout), common-wired DC layout with 7 blocks, including a reversing loop, into a DCC and DC operation in which, when I run in DCC (Bachmann E-Z Command), I engage a cutoff switch which denies DC power to all blocks and the common. I kept the DC operation option because I have a number of 30-year old brass locos that I want to keep operating that way, but I also have some newer DCC On Board locos and want to get into sound. I realize the danger here, but long as I am the only one operating the layout, I’ll take the risk of burning out either a loco or a transformer/control if I accidently power both systems at once. And everything has been running just fine until the last few days.
My single main line has two blocks. Recently, after a few minutes of OK operation, when a loco operating in DCC hits block #2, it stops dead. I tested the track on block #2 with my multi-tester and, when this happens and the loco is sitting at the beginning of block #2, there is no power to the track. Sometimes when I run a loco into the other end of block #2, it runs a few feet in to the block and then shuts down - same thing, no power to track showing on the meter. I pull the engine, shut down the entire system for a few minutes - say 5- and sometines, but not always, when I power it up again, block #2 runs for awhile, then shuts down when an engine hits it or has run part way in to it. No engine burn out, no apparent damage to the E-Z Command control, no smoking contacts, all other blocks, including the reversing loop operate fine in DCC. The same phenomemon happens when I run a DC engine on the one analog loco operating circuit on the E-Z Command.
Something is causing the block #2 circuit to open somewhere when an engine bridges the gap, but the usual short circuit flashing and clicking on the E-Z Command control does not occur.
Has anyone got an idea about what is wrong and how I can