Hello, I have some old engines that do not have DCC decoder or it is too expensive to convert them. I know we can run the engine with no decoder on DCC layout, but if it is not running there is that humming sound and DCC manufacturers do not recommend to leave these engines on the tracks for a long time. Is there a way to have a layout with both DCC and DC. I know we can make one of the line just for DC, but I wonder if there is a better way to do it? Thanks. Mo
The answer is yes, but explaining the necessary steps is not always so simple. Simply put, you can wire your layout for traditional DC block control and treat DCC as just another cab. It's much better to completely insulate the blocks and not to use common rail wiring, although common rail can be done. Additional precautions are necessary with common rail. I don't really know enough to stick my neck out and explain it completely, but I know for example at our club that our DCC boosters all have optical isolation from the Digitrax Loconet connection to deal with these issues. If you have a DCC layout that was not initially wired for cab control, then it's going to be a lot of work to implement it.
Most of us have the same dilema as you describe. Too many engines, not enough money! So.. what I have done is mounted a toggle switch in my control panel that switches the layout between DCC and DC. You need to have isolated areas (blocks) to park the DC and/or DCC locomotives while not in use when running in DC. As any good DCC or DC wiring manual will recommed, you should use good wiring practices whether you're DC or DCC. That includes multiple power drops and isolated sections of track. In my case, my yard has each yard track blocked for parking DC trains and a separate toggle switch that turns all yard tracks off. This provides great flexibility for me when running an occasional DC Loco without pulling it on and off the track. OR... you could go with Digitrax which goes both DCC and DC. By selecting Loco No. "00", the DCC switches to DC. From what my friends tell me, it works just fine. Keep in mind, you are still going to need some type of "blocking" if you want to leave multiple DC locomotives on the track without having everthing take off when you open the throttle.
What I have done is similar to UPCLARK's toggle switch. My layout is set up so that it can either be all DCC or all DC, just by changing one electrical male/female power connector. Depending on the locos I run, I just set the power plug accordingly. Of course that means removing any DC locos off the track if I'm running DCC - but my layout is so small that this is not a problem. This has worked out very well for me. Hope this helps.
The best option is to make it DCC or DC at any one time. Having both available simultaneously is courting danger for the DCC system - they don't like foreign supplies back fed into the command station/booster. A switch arrangement using a two pole switch that breaks before it makes, or has a centre off position, or use a three position two-pole rotary switch set up as DC-off-DCC so the two supplies don't connect during switching. You can use this on the input (mains) or output (track) side depending on the size of layout or number of boosters, etc.
I have my shelf layout set up to do either/or.. I have a decoder wired permanently in line with the tracks... almost like the whole layout is the motor of the engine, if you will... if that makes sense. Then I have a dpdt switch between the main DCC power and the tracks. one way wires directly to the track power, the other is wired to that decoder. that lets me select from DCC mode to DC mode. When in DC mode I use the address of my permanent decoder, and that decoder runs anything that happens to be on the tracks at that time. does that make sense?
Instead of a switch, I have a plug. So I have an actual plug that I have to plug in for DCC or for DC throttle. I just bought some of the old Cinch Jones connectors. So there is no way I could ever have both running at the same time either. By the way, I also personally NEVER recommend running analog locomotives on a DCC layout using decoder address Zero. Even though that is supposedly for analog, I have had a loco motor burned out before. And that was after LOWERING the total voltage to the system. It's just not worth the risk.
