Newbie question on DCC

[OgreMike]

hello everyone. OgreMike here. I am a newbie, but I have been interested in model railroading for over 50 years. I’m finally making my first attempt to build a model railroad. I’m building the Atlas plan HO 36. It’s the Oregon Pass Lines. But instead of doing the old traditional, DC type of hook up, I would like to do DCC. The Atlas website suggests a very simple (and I suspect not good) DCC suggested hook up for that layout using Atlas Connectors. I’ve been reading up on DCC the last couple of days and it appears that today’s technology offers a world of betterment over the old traditional single and double throw toggle switches. Anyway, I’m getting into it and the first question I’d like to ask for anybody to answer is, are power districts, equivalent to the old blocks, essentially, in DC wiring? And, when setting up a power district (block) do I need to isolate BOTH rails from any adjoining power districts? In reading the literature, it appears that using the old common rail that DC likes to use is a bad thing to do. So there’s my first question. Thanks for answering! OgreMike

 

[dennis461]

Holey molely, that is a lot of layout for a beginner!
Yes, a power district should isolate both rails at each end of district.

Reversing loops also isolate both rails.
Turnout is a separate district

I'd start out with a tiny section of the layout.
Good luck.

 

[OgreMike]

Holey molely, that is a lot of layout for a beginner!
Yes, a power district should isolate both rails at each end of district.

Reversing loops also isolate both rails.
Turnout is a separate district

I'd start out with a tiny section of the layout.
Good luck.

Thanks Dennis. Yes, I was wondering about turnouts. Any elaboration on them is much appreciated. As it stands now, I plan on having about half the number of power districts as there are blocks in the original, DC layout shown in the atlas, king-size layout book. I’ve already got all of the framing cut out and put together and all of the plywood top cut appropriately per the book. I’ve also already got the lowest section of the track plan put in, and have just attached the joiner wires for both the inner and the outer parts. Since this is a reverse loop situation, I thought it would be best to start asking a few questions about DCC. Anyone please feel free to chime in.

 

[OgreMike]

BTW, anyone have a suggestion as to which DCC system would be good for controlling the OPL? Again, thanks everyone for chiming in.

 

[dave1905]

Wow, that's a lot of track in a small space.

Ho-36 Oregon Pass Lines, Ho Scale Track, All Scales Layouts| Atlas Model Railroad

The official online store for the Atlas Model Railroad Company, Inc. manufacturer and seller of model trains and track in N, HO, O and Z scales.

shop.atlasrr.com

Power districts are sorta like blocks but can be much larger. For example I have 8 power districts for a layout that fills a 24x24 room. You probably could get by with two or three power districts. The point of power districts is not as much to turn the power on and off (like in DC) but to install circuit breakers so if something shorts out it won't shut down the entire layout. I like to break both rails so there is no chance of a back feed from one block to the next and I do install a DPDT toggle into the feed to each power district so I can isolate it.

 

[dave1905]

BTW, anyone have a suggestion as to which DCC system would be good for controlling the OPL? Again, thanks everyone for chiming in.

Loaded subject. I like NCE, I've had my system for almost a decade, but each person who has a different system will advocate for their system.

One approach is to see what other local modelers use and get one of those systems. Or if you have a local hobby shop that specializes in one system or the other, buying that system might be a good idea. The benefit of those approaches is, you might not get the "best" system, but you will get a system that you have local "support" from other modelers or the hobby shop.

 

[OgreMike]

Wow, that's a lot of track in a small space.

Ho-36 Oregon Pass Lines, Ho Scale Track, All Scales Layouts| Atlas Model Railroad

The official online store for the Atlas Model Railroad Company, Inc. manufacturer and seller of model trains and track in N, HO, O and Z scales.

shop.atlasrr.com

Power districts are sorta like blocks but can be much larger. For example I have 8 power districts for a layout that fills a 24x24 room. You probably could get by with two or three power districts. The point of power districts is not as much to turn the power on and off (like in DC) but to install circuit breakers so if something shorts out it won't shut down the entire layout. I like to break both rails so there is no chance of a back feed from one block to the next and I do install a DPDT toggle into the feed to each power district so I can isolate it.

Thanks Dave. Great info, and I think you put it right when you said the point is not the power but the automatic CBs to cut the power in a district if something goes amiss. I like that. Great way to think about it! After all, it seems to me the whole point of having DCC in the first place was to get away from throwing block power switches on and off in favor of simply running trains anywhere one wants to. Great info. TY!

 

[OgreMike]

Loaded subject. I like NCE, I've had my system for almost a decade, but each person who has a different system will advocate for their system.

One approach is to see what other local modelers use and get one of those systems. Or if you have a local hobby shop that specializes in one system or the other, buying that system might be a good idea. The benefit of those approaches is, you might not get the "best" system, but you will get a system that you have local "support" from other modelers or the hobby shop.

Thanks Dave. From what I can tell so far, for a 12x8 layout like I’m building, I don’t think I need top of the line controls. I appreciate the feedback! Thanks!

 

[Iron Horseman]

The Atlas website suggests a very simple (and I suspect not good) DCC suggested hook up for that layout using Atlas Connectors.

I would not suspect that. In my opinion that is a pretty complicated DCC hook up. BUT they have to do it because ... see below

are power districts, equivalent to the old blocks

No.
Long answer. The reasons for power districts in DCC are 1. There isn't enough power for all the equipment. or 2. The isolation of shorts so one short on one side of the layout doesn't shut the whole thing down.

On a layout this size (maybe three trains simultaneously?) I don't think you need power districts because of too much current draw, unless you want to have a whole lot of sound locomotives idling in the yard somewhere.

Likewise I don't see a whole lot of opportunity for compounding shorts. Maybe make the yard a separate power district so the additional risk of shorts in that type of operation don't impact the trains on the main.

And having said all that, if one is planning on going with signaling it is a step off a cliff. If one is going to use track powered detection for said signalling it is a whole different story and yes then one needs lots of double insulated blocks.

when setting up a power district (block) do I need to isolate BOTH rails from any adjoining power districts?

No.
Long answer. DCC can be done with common rail also, but as above I don't think you need power districts. The issue for this layout isn't power districts but rather reversing loops. Looks to me the whole thing is a folded dog bone. Would be really simple to wire if it wasn't for the crossovers between the two tracks. I think I see four. Each one creates a reversing loop situation, and YES reversing loop sections have to have BOTH rails insulated. As a crossover isn't a long enough section of track for a full normal type reversing loop, one will have to have sections of the main line be reversing sections. Hence the complexity of the Atlas wiring diagram. With DCC that can all be simplified with Automatic reversing units.

Not totally understanding the track diagram especially on the upper right. I THINK I would do it this way. 4 auto reverses, yellow, red, green, and blue. With regular power to the pink places. Well maybe pull the pink on the upper right further down in the curve.

This arrangement gives the yard the possibility of switching on and off the main without continually tripping an auto reverser. Just running a train on the through track would set the reversers up one way and never have to trip them until a crossover is used.

 

[Iron Horseman]

I was wondering about turnouts. Any elaboration on them is much appreciated.

My opinion is using expensive DCC power for turnouts is a total waste of resource. They can be powered with inexpensive wall warts, why spend power from devices costing hundreds of dollars for them. And I think especially true on a layout this size. Routing and all that sort of advanced feature would be total overkill.

 

[Iron Horseman]

BTW, anyone have a suggestion as to which DCC system would be good for controlling the OPL? Again, thanks everyone for chiming in.

Any of the main brand systems will work fine. Major players are NEC, Lenz, Digitrax. Lesser players are the Zimo, Prodigy, and umm umm missing one here - someone chime in.

One of the finest is CVP but I've found them curmudgeon's to work with anymore. They never want to help one upgrade but rather just "buy a new system". Also AVOID the old MRC Command-2000. Totally obsolete. Seems like Bachmann had a base system that was too primitive. Finally while I mentioned NEC above I cannot recommend their "Twin". Looks really cool but very limited functionality.

And for the record I own, the MRC Command-2000, the NEC "Twin", a CVP Easy-DCC, a Digitrax Zephyr, but I consider my main systems to be the NCE PRO cab-r, and the Lenz. Wireless are sooo nice.

 

[Mixed Freight]

Hello OgreMike,

Heck of a railroad you're eyeballing for your first venture! But, if you've been interested in model railroading for over 50 years, then hopefully you're old enough and wise enough to know what you're getting into with this particular layout!

Pulling out the ol' Custom-Line King Size Plan Book, and refreshing my memory for a little bit, I would say that if one disregards the yard trackage for the time being, then the main layout all of a sudden doesn't look so insurmountable. Actually, looks like a pretty cool layout that would be fun to operate. Definitely old-school, though. And I hope you wouldn't plan on ever moving again, as it would be pretty tough tough to get out of a house if you ever needed to move.

If I were going to build this layout, I'd forget the sectional track and use all flex track, and solder most of the joiners (insulated rail joiners at the reverse loops, of course). Fewer rail joints that way. But, I have plenty of experience with flex track, and you may not.

I personally like and use an NCE DCC system on my home layout and club layout. NCE is very user-friendly in my opinion, and was easy to learn on (a big help for me at the time). There's other good systems out there also. dave1905's advice on a brand (post #6) is quite worthy of consideration.

As far as wiring the layout for DCC, this is what I would do: I wouldn't worry about power districts. It's not THAT big of a layout. Looking at the layout schematic in the book, it's really just a big dog-bone with a reverse loop at each end. Get two auto-reverse loop modules, one for each reverse loop. Then, in OVERLY SIMPLISTIC terms, from you command station run two wires to the left loop auto-reverser. Run two wires to the right loop auto reverser. Then run two wires to the trackage in between the loops. That's it! Pretty easy, eh?

Well, you'll actually be running more wires than that. BUT, due to all the turnouts, they will be nothing more than jumper wires to make sure all the tracks receive power. If you really want to do power districts, that wouldn't be hard to do either. I'd probably go with 4 districts - each reverse loop, the main layout in between the loops, and the yards. Or you could have even a few more, that would be totally up to you.

As far as turnouts go, I'd probably just use Atlas powered turnouts on the mainline along with their little electrical switches. And any other places maybe a little far to reach. And just go with hand-throw turnouts in the yard and any other close-by turnouts.

Well, that's my advice, hope it's of some help. Good luck with whatever you end up doing.

 

[OgreMike]

I would not suspect that. In my opinion that is a pretty complicated DCC hook up. BUT they have to do it because ... see below


No.
Long answer. The reasons for power districts in DCC are 1. There isn't enough power for all the equipment. or 2. The isolation of shorts so one short on one side of the layout doesn't shut the whole thing down.

On a layout this size (maybe three trains simultaneously?) I don't think you need power districts because of too much current draw, unless you want to have a whole lot of sound locomotives idling in the yard somewhere.

Likewise I don't see a whole lot of opportunity for compounding shorts. Maybe make the yard a separate power district so the additional risk of shorts in that type of operation don't impact the trains on the main.

And having said all that, if one is planning on going with signaling it is a step off a cliff. If one is going to use track powered detection for said signalling it is a whole different story and yes then one needs lots of double insulated blocks.


No.
Long answer. DCC can be done with common rail also, but as above I don't think you need power districts. The issue for this layout isn't power districts but rather reversing loops. Looks to me the whole thing is a folded dog bone. Would be really simple to wire if it wasn't for the crossovers between the two tracks. I think I see four. Each one creates a reversing loop situation, and YES reversing loop sections have to have BOTH rails insulated. As a crossover isn't a long enough section of track for a full normal type reversing loop, one will have to have sections of the main line be reversing sections. Hence the complexity of the Atlas wiring diagram. With DCC that can all be simplified with Automatic reversing units.

Not totally understanding the track diagram especially on the upper right. I THINK I would do it this way. 4 auto reverses, yellow, red, green, and blue. With regular power to the pink places. Well maybe pull the pink on the upper right further down in the curve.

This arrangement gives the yard the possibility of switching on and off the main without continually tripping an auto reverser. Just running a train on the through track would set the reversers up one way and never have to trip them until a crossover is used.
View attachment 157013

Wow, great info Iron! Thanks a bunch! In thinking more about it, maybe the best way is to use the Atlas DCC hookup but supplement it with CBs for each section they show in the hookup, along with combo cb/reverse loop adapters for each of the reverse loop areas. Also, if the cb’s are equipped with led‘s indicating which section is having a problem, that would be good. The connectors shown in Atlas’ DCC scheme would simply be manual power removers to ensure power to the affected section is affirmatively off until the shorting problem can be cleared. Thoughts? Or am I missing something?

Hello OgreMike,

Heck of a railroad you're eyeballing for your first venture! But, if you've been interested in model railroading for over 50 years, then hopefully you're old enough and wise enough to know what you're getting into with this particular layout!

Pulling out the ol' Custom-Line King Size Plan Book, and refreshing my memory for a little bit, I would say that if one disregards the yard trackage for the time being, then the main layout all of a sudden doesn't look so insurmountable. Actually, looks like a pretty cool layout that would be fun to operate. Definitely old-school, though. And I hope you wouldn't plan on ever moving again, as it would be pretty tough tough to get out of a house if you ever needed to move.

If I were going to build this layout, I'd forget the sectional track and use all flex track, and solder most of the joiners (insulated rail joiners at the reverse loops, of course). Fewer rail joints that way. But, I have plenty of experience with flex track, and you may not.

I personally like and use an NCE DCC system on my home layout and club layout. NCE is very user-friendly in my opinion, and was easy to learn on (a big help for me at the time). There's other good systems out there also. dave1905's advice on a brand (post #6) is quite worthy of consideration.

As far as wiring the layout for DCC, this is what I would do: I wouldn't worry about power districts. It's not THAT big of a layout. Looking at the layout schematic in the book, it's really just a big dog-bone with a reverse loop at each end. Get two auto-reverse loop modules, one for each reverse loop. Then, in OVERLY SIMPLISTIC terms, from you command station run two wires to the left loop auto-reverser. Run two wires to the right loop auto reverser. Then run two wires to the trackage in between the loops. That's it! Pretty easy, eh?

Well, you'll actually be running more wires than that. BUT, due to all the turnouts, they will be nothing more than jumper wires to make sure all the tracks receive power. If you really want to do power districts, that wouldn't be hard to do either. I'd probably go with 4 districts - each reverse loop, the main layout in between the loops, and the yards. Or you could have even a few more, that would be totally up to you.

As far as turnouts go, I'd probably just use Atlas powered turnouts on the mainline along with their little electrical switches. And any other places maybe a little far to reach. And just go with hand-throw turnouts in the yard and any other close-by turnouts.

Well, that's my advice, hope it's of some help. Good luck with whatever you end up doing.

Thanks Freight! I’ve got a lot of great ideas here. Thanks! I’ll be posting and asking more questions as I go along, I’m sure!

 

[PowrCab]

Hi,
Admittedly I did not read all the posts..But just wanted to say this:
If your layout is small to medium sized, put power districts out of your mind !!.. Except for special attention to any and all reverse loops, which, in DCC only require the correct hook up of an AR (auto reverser) to control them, take all blocks out of you layout, employ 'all-live' switches (TOs) as opposed to 'power routing' switches and hook the 2 (as in "two") wires from back of your NCE PowerCab panel or your Digitrax controller to 2 rails and you're in !! DATS IT !
Power districts are needed on huge layouts such as club layouts for a couple reasons I don't need to explain here. Even the schematic Iron Horseman shows in post #9 you can easily run 2-3 trains at a time (as now you CAN with DCC) with no 'district power booster' required..
At least try it this way before getting deeper involved and see what happens, first.. I'll bet you stay with the one single DCC controller...
If not, then add / splice cut in a 'power district' / booster if trains are seemingly slowing down when farthest from those initial 2 wires...
As long as all your track connections are solid and your reversing sections under correct control you should be all set to go.. (While, of course, getting to know and understand DCC control better and better as you go along)..

 

[OgreMike]

Hi,
Admittedly I did not read all the posts..But just wanted to say this:
If your layout is small to medium sized, put power districts out of your mind !!.. Except for special attention to any and all reverse loops, which, in DCC only require the correct hook up of an AR (auto reverser) to control them, take all blocks out of you layout, employ 'all-live' switches (TOs) as opposed to 'power routing' switches and hook the 2 (as in "two") wires from back of your NCE PowerCab panel or your Digitrax controller to 2 rails and you're in !! DATS IT !
Power districts are needed on huge layouts such as club layouts for a couple reasons I don't need to explain here. Even the schematic Iron Horseman shows in post #9 you can easily run 2-3 trains at a time (as now you CAN with DCC) with no 'district power booster' required..
At least try it this way before getting deeper involved and see what happens, first.. I'll bet you stay with the one single DCC controller...
If not, then add / splice cut in a 'power district' / booster if trains are seemingly slowing down when farthest from those initial 2 wires...
As long as all your track connections are solid and your reversing sections under correct control you should be all set to go.. (While, of course, getting to know and understand DCC control better and better as you go along)..

Thanks for this great input, Power Cab! Appreciate it! Super advice here. And it sure does seem appealing! Start simple and only get more complicated as the layout dictates. Love it!

 

[OgreMike]

Hey again Power Cab (and everyone else who has so kindly provided input to this newbie). Another question: wrt track wiring leads hookups . . . Do all of you solder your connections? The track package I bought from Train Sets Only contains rail joiner wiring connectors which might be ok, but it looks like the wires on these are only 16 gauge. Anyone have experience with these? I’ve been reading that 14 gauge for a layout the size of the OPL might be better? Thanks in advance to all of you who’ve posted input! Can’t thank everyone enough!

 

[Selector]

The 16 gauge wire is what we call 'feeders'. They are meant to provide bi-directional (ideally) power to at most 10 contiguous feet of track. However, the joiners, themselves, are notoriously ineffective over time. They aren't bad for mechanical alignment, but they're terrible for reliable electronic relay to either side of them, from the joint outward. That's why we solder those joiners, to ensure the close contact between the joiner and the rails they're aligning.

By the way, while some insist on soldering all/most joiners, you don't need to do that. You want reliable bi-directional power down to a defined limit. The way you do this is to solder every other joiner, and leave the others free to slide a bit to accommodate shifting of the benchwork due to both temperature and humidity swings in the train room. Temps comprise maybe 15% of the worry, humidity is what causes the lion's share of the problems with buckling rails.

Schematically, the way you want to power the rails are thusly:

= is the rails, x is soldered joiner (closed circuit), and o is open joiner left to slide:

======o============x===========o===========x===========o====

As you can see, by soldering every other joiner, you get robust and reliable soldered power both ways until the next 'iffy' joiner....which doesn't need to do anything except to align the rail ends.

 

[Iron Horseman]

Power Cab (and everyone else who has so kindly provided input to this newbie).

Good choice there will be lots of folks who can help with that if you ever have problems.

Another question: wrt track wiring leads hookups . . . Do all of you solder your connections? The track package I bought from Train Sets Only contains rail joiner wiring connectors which might be ok, but it looks like the wires on these are only 16 gauge. Anyone have experience with these? I’ve been reading that 14 gauge for a layout the size of the OPL might be better?

I solder the wires directly to the rail. That is a choice not a requirement. The rail joiner connections are OK if you put them on exactly once and never disconnect them. Each time they are taken off and put back on they get weaker and weaker. In my opinion that is not just for joiner connections but every rail joiner on the layout. If they cause trouble at a later time - then you could solder them.

No, in general I do not solder track connections. At my former club I was amazed at the amount of stress 1/64" heat expansion of a nickel silver rail put on the track that we had not left expansion joints in. Now, the only rail joiners I solder are those on flex track on a curve, and for certain I do not solder them first. I put them into place then solder.

The wire gauge. 14 gauge for a layout this size is totally over kill, as would be a power "bus". It never hurts to go bigger but why use wire that is expensive and you have to fight with rather than cheaper easier to work with things. I did a smaller layout with a bus once. Figure I wasted about 20 hours and $60 doing that. Never again. My office layout is 12 x 9. It is powered by 4 feeds of 18 gauge wire equal distance around the track. Runs perfect.

I've posted this before, but since it fits the discussion. I've always wished for square wire.

 

[OgreMike]

Thanks for all your great input Iron!! Very much appreciated!

 

[OgreMike]

The 16 gauge wire is what we call 'feeders'. They are meant to provide bi-directional (ideally) power to at most 10 contiguous feet of track. However, the joiners, themselves, are notoriously ineffective over time. They aren't bad for mechanical alignment, but they're terrible for reliable electronic relay to either side of them, from the joint outward. That's why we solder those joiners, to ensure the close contact between the joiner and the rails they're aligning.

By the way, while some insist on soldering all/most joiners, you don't need to do that. You want reliable bi-directional power down to a defined limit. The way you do this is to solder every other joiner, and leave the others free to slide a bit to accommodate shifting of the benchwork due to both temperature and humidity swings in the train room. Temps comprise maybe 15% of the worry, humidity is what causes the lion's share of the problems with buckling rails.

Schematically, the way you want to power the rails are thusly:

= is the rails, x is soldered joiner (closed circuit), and o is open joiner left to slide:

======o============x===========o===========x===========o====

As you can see, by soldering every other joiner, you get robust and reliable soldered power both ways until the next 'iffy' joiner....which doesn't need to do anything except to align the rail ends.

Thanks Selector for all the great feedback from all of you. I’m trying to take it all in and make a good plan for DCC wiring. You guys are super! Makes the task ahead of me feel that much less daunting to be able to talk with you all!