Running both DCC & DC locos on the same layout.

[learmoia]

Another thing to consider if your going to stick with block wiring and toggles.. Instead of retaining a DC controller as your 2nd block..

You could use an HO (or O) Decoder's Motor outputs as your "DC" Controller.. (Program the decoder's Min-Mid-Max voltage to your liking so you don't overvolt the N scale locos) then everything is controlled within the DCC system (without using 00).  (The HO or O decoder allows greater Amp Draw if needed before the decoder overloads.)

~Ian

[peteski]

You could use an HO (or O) Decoder's Motor outputs as your "DC" Controller.. (Program the decoder's Min-Mid-Max voltage to your liking so you don't overvolt the N scale locos) then everything is controlled within the DCC system (without using 00).  (The HO or O decoder allows greater Amp Draw if needed before the decoder overloads.)

~Ian

https://sites.google.com/site/markgurries/home/dcc-bad-ideas

https://sites.google.com/site/markgurries/home/technical-discussions/dc-loco-on-dcc

Actually, I recommend perusing Mark's entire DCC website - lots of very helpful, and educational info, written in a way that an average person can understand. No need to be electronci or computer expert.
https://sites.google.com/site/markgurries/home

[wm3798]

I'm toying with the idea of making my upper loop convertible to DCC, since it's the Western Maryland line, and I still have a fleet of DCC locos that gather dust in the cabinet.  Of course, my track plan is dirt simple, with no real need for engines to cross from one plane of existence to another.  All of my switching is via "0-5-0" so there's no risk of putting the wrong power to the wrong engine... at least not for very long.
I also have a growing fleet of DC old school WM gear, so the matter is less urgent.

My other option is to build yet another layout!

Lee

[jagged ben]

Just make sure that you never ever, ever,ever, ever allow a locomotive cross between live DC and DCC power blocks.  Did I mention "never"?  SInce we know that mistakes can and will happen, it would make sense to keep the DC and DCC parts of the layout completely separate (no possibility of crossing).

...

You are exaggerating the danger.  On our club layout, which was originally wired for DC block control, we have the DCC system wired in as an additional cab.  Locomotives crossing between systems happens sometimes through operator error and its almost entirely a non-issue (other than from a realism point of view).  DCC decoders these days are of course designed to run on DC if the option is turned on.  DC locomotives will buzz and not move if exposed to DCC voltage, but it's happened to me more times than I can remember and there's never been any damage when it's for less than a minute.  The buzz is quite attention-getting so you'll just immediately undo whatever you did that started it (flip the switch back, grab the loco back off the track, 0-5-0 the train back out of the block).

The one notable exception, that I know about, was a DC locomotive that contained some fancy lighting electronics from Richmond Controls.  They were immediately fried when that loco overran into a DCC block.   I doubt anyone still installs that stuff since you'd go with DCC nowadays if you're into lighting effects.  But if you still have locomotives with that old-school stuff installed, and you want to run them, then never, ever, ever, ever let those locos wander into a DCC block. 

[peteski]

I'm toying with the idea of making my upper loop convertible to DCC, since it's the Western Maryland line, and I still have a fleet of DCC locos that gather dust in the cabinet.  Of course, my track plan is dirt simple, with no real need for engines to cross from one plane of existence to another.  All of my switching is via "0-5-0" so there's no risk of putting the wrong power to the wrong engine... at least not for very long.

The real problem is not which engine under which power. No o smoke would be released by the engine (unless a DC coreless motor engine sat on DCC powered track for extended time). The real danger is shorting those 2 power systems together (with or without the engine on them).

[peteski]

You are exaggerating the danger.

Maybe so, but better safe than sorry.  IMO, there is no good reason to mix DCC and DC in a way that both power methods can somehow get connected.  I call that "best practice".

[jagged ben]

Maybe so, but better safe than sorry.  IMO, there is no good reason to mix DCC and DC in a way that both power methods can somehow get connected.  I call that "best practice".

The good reason, as alluded to by the OP,  is to run DC locomotives that you wany to run but may not have the time, money, or skill to convert.   In my experience it's really nice to have the option, and there aren't any serious downsides.  Your mileage may vary.  I disupte that there's any 'best practice' here that isn't soundly outweighed by rule #1.

[jagged ben]

The real problem is not which engine under which power. No o smoke would be released by the engine (unless a DC coreless motor engine sat on DCC powered track for extended time). The real danger is shorting those 2 power systems together (with or without the engine on them).

There's one aspect of these people should know, which is that if you have a 'common rail' system, you need to have DCC boosters with optical isolation on the Loconet (or equivalent).  This is apparently needed to keep the comms wire from becoming an inadvertent parallel path for track current.   This is only needed if you are using common rail.  If you switch both rails from the source it's not necessary.   Digitrax will provide these boosters if you ask them, I don't know about other DCC brands.

Otherwise, there's no more danger of shorting two power sources to each other than there is with multiple DC cabs, as people have done for many decades with no issues.  It is not possible to 'short' separate power sources to each other.   That's kind of fundamental to electrical theory.

[CRL]

I’ve never used common rail wiring. I know it’s supposed to be easier, but I prefer duel rail wiring since it’s easier for me to keep the rules straight in my head on where to put the gaps.

[jagged ben]

I’ve never used common rail wiring. I know it’s supposed to be easier, but I prefer duel rail wiring since it’s easier for me to keep the rules straight in my head on where to put the gaps.

Then you are probably good to go.   

A simple test to eliminate the kind of issue Pete is worried about would be to set your DCC booster and DC cab next to each other and turn them both on.  Use a multi-meter to first confirm that each one has voltage at its track terminals.  Then measure voltage between each terminal and the terminals on the other source (4 combinations, times 2 for measuring both AC and DC).  You shouldn't get any voltage, and if you don't you should have no problems connecting them to different blocks.

I agree that common rail wiring isn't objectively easier.  It's fewer connections to make, but can be more confusing and harder to troubleshoot.   

[peteski]

The good reason, as alluded to by the OP,  is to run DC locomotives that you wany to run but may not have the time, money, or skill to convert.   In my experience it's really nice to have the option, and there aren't any serious downsides.  Your mileage may vary.  I disupte that there's any 'best practice' here that isn't soundly outweighed by rule #1.

I'm not against having a DC/DCC layout at all. Just feed the entire layout from a DPDT switch to which you connect the DC throttle and DCC booster.  You can easily flip between the system with no possibilities of "crossed wires" or crossed blocks.  And yes, that means entire layout would be single block.

To be honest, using DC and DCC on a multi-block layout (where each block can be connected to some DC throttle or DCC booster) seems awkward to operate.

[jagged ben]

I'm not against having a DC/DCC layout at all. Just feed the entire layout from a DPDT switch to which you connect the DC throttle and DCC booster.  You can easily flip between the system with no possibilities of "crossed wires" or crossed blocks.  And yes, that means entire layout would be single block.

To be honest, using DC and DCC on a multi-block layout (where each block can be connected to some DC throttle or DCC booster) seems awkward to operate.

I think it's hard to argue that it's more awkward to operate than multi-cab control was when it was all DC cabs.    It's true that being all DCC takes that away.  On the other hand, with enough operators you need a dispatcher to control the blocks anyway. 

[peteski]

I think it's hard to argue that it's more awkward to operate than multi-cab control was when it was all DC cabs.    It's true that being all DCC takes that away.  On the other hand, with enough operators you need a dispatcher to control the blocks anyway. 

If that was a DC/DCC layout with multiple blocks.there are plenty of possibilities for mistakes: dispatcher incorrectly assigning throttle/DCC to a block, or operator running a block boundary.  Even if everything went smoothly, it would really be hard to justify running a DCC loco using DCC signal on such a layout, traversing one block at a time (while paying attention not to run a block).  Just enable DC operation on any decoder-equipped loco, and run it with a DC throttle, like any DC model.

[jagged ben]

Again, I see nothing here that outweighs rule number one.  It just depends what you've got and how you want to run it.

[peteski]

Again, I see nothing here that outweighs rule number one.  It just depends what you've got and how you want to run it.

True, but this thread was started asking for advice and opinions.  Those were provided. What you or others do with those, it is totally up to all ya all.  I know what I would (or wouldn't) do.