Large Scale Central

Another basic question on DDC setup

I am doing a dog bone with a reversing loop on each end. Now I know they have to be isolated and separately powered. Does the DCC unit automatically reverse polarity when it recognizes it or am I going to need to install something to reverse polarity?

I know in DC this was a tricky problem but if I understand it right DCC fixes the problem.

With DCC you will have to isolate both rails on each end of the loop. There is a unit that is sold that is wired into those two isolated rails with just two wires, that is the unit gets its power from the main rails and runs the power thru the reversing unit to the isolated area. Presto it all done for you, you never have to throw a switch to reverse power and all mechanical procedures are done for you. The reversing takes place when the engines two front wheels (metal wheels) touch the area on the other side of the reversing area, this causes the reversing controller to change the polarity and the reversing is automatically done within the unit. The amazing thing is you will never see the engine running make a sudden start, or stop, it with go over the area between the reversing loop and the main rails smoothly. I have the NCE system on my HOn3 layout and it works perfect, you will never think about the reversing loop again. One thing I’m not sure of is if one reversing unit can do more then one reverse loop, or does it take one for each loop, my layout only has one unit and I use it on the turntable and I have no reversing loops on my layout. Here is one offered by NCE, cedcc.zendesk.com/hc/en-us/articles/203171505-NCE-AR10

trainman

Thats how I thought it worked. Interesting question about whether one unit could handle both reversing loops. Even though I said they are at each end they will actually be stacked on one another. The dog bone will be stacked on top of one another. 2.5% grade gets them the clearance as it runs out and back. So if one unit could do both that would be Interesting. My only thought is multiple trains would mess it up. If one train were on each loop and one triggered it would it reverse both loops causing problems for the other.

How to use reversing loops with DCC is dependent on whether you run just one train or multiple trains on the same track and one must be aware of a possible conflict if 2 trains are entering/leaving the same loop. And do not forget that the metal wheel cars can also cause a reverser to activate.

I want the ability to run multiple trains. One on the main and others switching. But thats the dream. Continuous running of the main line is more important. So running the loops takes precedent over multiple trains running.

Devon Sinsley said:

I want the ability to run multiple trains. One on the main and others switching. But thats the dream. Continuous running of the main line is more important. So running the loops takes precedent over multiple trains running.

That sounds fairly easy, Devon. You select your loco, send it to the main line, align your mainline switches to close the loop, and just leave the train running there. Then select a different loco and run that. If you want to alter speed / direction of the one on the mainline, you reselect that loco to give it the new commands.

But will the train on the mainline reverse the polarity of the entire layout when it reverses the loop?

My problem is I still think in DC when talking DCC and know I cant do that. I really have very little understanding of DCC and honestly don’t really want to know the technical stuff. Its supposed to be plug and play and I just want to plug and play. But I know I must also know what it can or can’t do. Ugh.

It’s confusing to me as well, haha! I can only speak to the loop controller I use, the PSX-AR from DCC Specialties. So here goes, in layman’s terms, cuz it’s all I got (but Dan & others will correct me where I’m wrong).

There’s a track section in the middle of the loop that the controller is controlling (vs. the entire mainline). The controller has a pair of wires coming from the loop’s entry and exit legs, and a pair going to the controlled section. When the train enters the loop, and the first metal wheels cross the gap to the controlled section, the PSX unit immediately brings that middle section into alignment with the phase of the entry leg. Each additional par of metal wheels tell it to do the same thing, but since all is in alignment those redundant “commands” don’t do anything.

When the loco comes to the gap at the end of the controlled section, there’s a little spark and the PSX unit flips the phase of that section to align with the exit leg of the loop. Further metal wheels do the same, but again to no further effect.

However, if your train is longer than the controlled section of the loop, your end cars’ wheels may be telling the PSX to align one way, while the loco is doing the opposite. Then you get a short. That’s why your return section has to be longer than your longest train.

Hope that helps,

Cliff

Remember with DCC you are controlling each engine separately through the rails and that signal is controlling the module in the engine you are running at that time. Remember if you are running an engine and you switch to another engine on your handheld you now have control of that engine and the engine that you were running will run at the speed that you left it, or parked and just setting there running when you switch to the other engine. You could have 10 engines running at the same time, but you and only make adjustment to the engine you have dialed in on your handheld, thus when you make adjustment to the engine you are controlling it does not effect the other and there running. I find it a full time job keeping up with two engine running at one time, I usually just do one at a time for the obvious reasons. One thing to remember is, don’t get confused on the rails getting their polarities switched when coming out of the reversing loop, that’s not what happens, the module in the engine is switching the polarities internally is where this happens, not in the tracks. There is no similarities between DC and DCC, you would be best to not think that the two work somewhat the same, they don’t.

trainman

Okay John you answered it for me. Its not the track being switched but the loci itself internally. That makes total sense now. Simple once you understand what is actually happening

When using a main line and yard engines at the same time, DCC does not care if the power is switched. What does matter is if the main line has a reversing loop separate from the yard, you must make sure the yard engine has enough track isolation from the main line if it enters the main line and does not cross the reverse loop isolation when the mainline engine crosses the other isolation.

When I said engines I really meant consists of engines and cars with metal wheels.

Myself I do not have a reversing unit and I run 2 to 3 trains on my layout, one loop is just completely separate from the other.

Devon Sinsley said:

Okay John you answered it for me. Its not the track being switched but the loci itself internally. That makes total sense now. Simple once you understand what is actually happening

I went through the same thing when I wanted to switch to DCC and always had DC. My first experience with DCC was on my HOn3 layout, all of Blackstone’s engines were DCC and my only option was to go with it. I will say here it was great from the start and I went with NCE and there system was easy to operate and learn, it’s not totally plug and play, but its close to that. For my G scale indoor layout I have gone from DC to RailPro RC battery powered engines, wow, no more rail powered systems, I can run my engines on any layout track powered, or not, they even run on the hardwood floors in the house. Give this some thought when thinking about a new operating system, there are advantages of battery power over DCC, now are you totally confused.

trainman

John Lenheiser said:

Devon Sinsley said:

Okay John you answered it for me. Its not the track being switched but the loci itself internally. That makes total sense now. Simple once you understand what is actually happening

I went through the same thing when I wanted to switch to DCC and always had DC. My first experience with DCC was on my HOn3 layout, all of Blackstone’s engines were DCC and my only option was to go with it. I will say here it was great from the start and I went with NCE and there system was easy to operate and learn, it’s not totally plug and play, but its close to that. For my G scale indoor layout I have gone from DC to RailPro RC battery powered engines, wow, no more rail powered systems, I can run my engines on any layout track powered, or not, they even run on the hardwood floors in the house. Give this some thought when thinking about a new operating system, there are advantages of battery power over DCC, now are you totally confused.

trainman

No more confusion there. All my G stuff is RC/Battery. Now that I am the proud owner of a small collection of O that I will use outdoor on a Fn2 run that will be a mining tram expansion to my garden layout I will even convert it to RC/Battery. In selling Steve Featherkyle’s O collection for his wife I could not resist buying his Spokane, Portland, & Seattle FA units and passenger coaches and a nice little GN Alco RS3 and a few cars to make a MOW train. I started that way in garden RR and don’t know why anyone would do anything different outdoors.

The DCC questions are coming from the very close to launching date of the construction of my hobby room On30 layout.

I’m personally missing Steve.

Rooster said:

I’m personally missing Steve.

You have no idea. I met Steve in the local club. He and I hit it off right away. He was Former Marine/navy so was I. Both loved RR history. Both loved trains. Our political and religious views were pretty much identical. Both Boy Scout and Both leaders in Boy Scouts. Both love the outdoors. The list goes on. It has been very tough sorting through and selling his stuff. Seeing the pain in his wife’s eyes as we carted off. He will be forever missed. “Take to Motrin and change your socks” was Doc’s answer to everything.