DCC & Double Track Mainlines

[kenkal]

I'm currently laying the roadbed for my layout and will soon be doing the track and wiring for DCC. I planned for a double track mainline. I don't have a DCC system yet, but will before long. I don't know much more than a LOT of reading about DCC (we're talking definite armchair DCC novice at this point). There is such an overwhelming amount of help from so many wonderful sites. However, I have been unable to find anything on the various sites about DCC considerations for double track mainlines.

Any there any special wiring considerations for double track mainlines? If wired as TWO separate (double gapped) sub-districts from ONE command station, does a train crossover without problems from one main to the other?

Does the direction the trains are running make a difference--i.e., if a train is westbound on a normally westbound mainline, and crosses into the eastbound mainline where another train is already running east bound, does the CROSSING OVER train continue as westbound, or do I get a short circuit or does either train stop or what? I'm confused I guess, because aren't we supposed to keep the right rail - and the left rail +? Well then, the west bound would be traveling from a west + to east - and west - to east + on the other mainline, no? Or am I hopelessly confused here?

Thanks for any help you can provide. Ken

[canazar]

Ken,
I run 2X mian on my lay out and our club runs a 2X main as well. You put wires just like any other layout.. Both side, inners and outers. Only thing you have to do, is when you have a cross over, insulate were the two line meet between the switches.

I run my switches set next to each other and at that joint, were the two meet, I just used the plastic joiners to seperate. The are other facnier ways to do it, useing plastic as an example that will work. Just a slong as the two dont touch,

I am useing off rack standard Code 100 Atlas switches and track. You can run your trains in any direction, at anyspeed , at anytime. Of course, you do have do tobe careful, because you can send one train down heading right toward another one and they will have a head on. Not that hasnt happened to me..... uh, [8)]it happened to my freind..

Hope that helps. Iam sure someone else will chime in with a bit more expeirence than me.

[SP4449]

Ken,

Wire each main is if the other doesn't exist, and to make it easy, wire one main at a time and test operations before starting on the other main. Connect a feeder from the two wire track bus for that main track to its corresponding rail for each section of track that has been joined to the previous rail by a metal rail joiner. Soldering the rail joiners to the rail is a good idea to help reduce the feeders but the more feeders you use, the more reliable the running. Use wires with different color insulation for each of the track bus wires - ie, black and red. Wire feeders to the black one to its rail first, then go around and wire feeders to the red one to its rail making sure you don't connect a feeder from the red wire to a rail already connected with a feeder from the black wire. If you want, you can use four different colors, red/black for Main 1 and yellow/green for Main 2.

Where a crossover connects Main 1 to Main 2, install INSULATED RAIL JOINERS on BOTH rails when joining the turnouts to each other. By using DCC friendly turnouts - ie: Atlas or PECO InsulFrog, no further feeders are required unless the turnouts are seperated by a section of track. In that situation, just use the insulated joiners on one of the turnouts and wire feeders to the section of track from the opposite main.

Use a seperate BOOSTER for each main line and the crossing from one main to the other will not be a problem so long as both turnouts are properly lined for the train to traverse the crossover. The CONTROLLER is keeping track of the train and when crossing from one main to the other, it will switch to the corresponding BOOSTER to continue to run the train. This is where DCC really shines: direction of travel is not dependent on the polarity of the power to the rails - except in a reverse loop.

In the reverse loop situation, a reverser is needed to prevent a short when the train crosses back on to the track from which it entered the loop.

Good luck.

[dehusman]

The key is how you have configured your two main lines. Are they two separate tracks or did you make two main tracks by squeezing an oval until the sides touched (a dogbone or barbell shape)?

If you did the dogbone shape then you need to put gaps across all the rails leading into each loop and put an automatic reversing unit across the gaps (one unit per loop).

Once you've done that you can wire the other tracks and mains into the same bus wires. ALL the left rails into one wire and ALL the right rails into the other. It won't matter which track or which direction any train will be on.

If your layout is point to point double track or a double track oval type of configuration then wire all the inside rails to one bus wire and all the outside rails to another bus wire.

Dave H.

[kenkal]

Thank you canazar, Dave and SP4449. It looks like I should not have a short problem, which was my biggest concern. I hate to be a bother, but I think, being the DCC novice that I am, I need just a little more clarification from your pretty helpful answers so far.

To clarify on my part and put it simply, let's say my two mainlines are basically 2 separate ovals with crossovers between the ovals. This is NOT a dogbone pattern. I planned to run normally eastbound Oval A off a circuit breaker from the control station and normally westbound Oval B off another circuit breaker from the SAME control station. I am NOT using a separate booster for one of the lines.

Does that change any one's answer? Dave, is your answer based on NOT using circuit breakers? If so, I may drop the circuit breaker thought for simplicity and just directly use the one control station.

Thanks again, guys. It sure is helpful and satisfying when a guy can get answers from those willing to share their wonderful knowledge. Ken

[rrinker]

I have a similar setup, and ran two sets of bus wires, oen for the inner loop and one for the outer loop. These will be connected to different circuit breakers. At the crossovers between the inner and outer loops, I insulated the joints.

--Randy

[wrumbel]

I have a double oval loop layout on a 4 x 6 foot piece of plywood. I'm using atlas turnouts and atlas code 100 track. I built this to test wire my DCC system to, I too had never worked with DCC. I've got 3 crossovers and 2 sidings, one is my program track. The only place I used insulated joiners was for the program track. I install a decoder, place the engine on the program track, get the address set, then run it around and make sure it's running right. I've mued engines and run them, I have had three different engines running on this small layout. Some day I might get around to running bus wires, but I think that will wait until the new layout is started.

Wayne

[Texas Zepher]

QUOTE: Originally posted by kenkal
[To clarify on my part and put it simply, let's say my two mainlines are basically 2 separate ovals with crossovers between the ovals. This is NOT a dogbone pattern. I planned to run normally eastbound Oval A off a circuit breaker from the control station and normally westbound Oval B off another circuit breaker from the SAME control station. I am NOT using a separate booster for one of the lines.

Should be straight forward. The only reason you will need insulated joiners between the turnouts of the crossovers is because of the two separate circuit breakers.

There will be no problems passing from one track to the other. This would be true even if they were on seprate boosters.

[kenkal]

Thanks rrinker, wrumble and Texas Zephyr. I 'm getting more confidence by your comments that I won't have a disaster when I get this thing going. I appreciate your input. Ken

[SP4449]

The main reason for seperating the loops is to keep a short circuit caused by a screw driver dropped on the track of one of the loops shutting the entire system down. You have gotten that protection with the seperate breakers. Boosters perform the same function as circuit breakers, so you are ok.

Have fun. DCC rules.

[Dproline]

OK GUYS, like KenKal posted 03 july, am building double track main in a reasonable size basement 30x35.like main line action, large yards,and signaling.have brass,life-like, athern,atlas,and now BLI w/sound! would like to go DCC. without trying to open a can of worms, what might be the best system for me? Digitrax seems to be most popular.

[rrinker]

What do other people in your area run? Is your LHS versed in one particular system or another? These are important questions if you are new to this.

And the usual - you gave your proposed layout size. Now, how many locos do you see running at the same time, and how many people do you see running trains?

--Randy

[Anonymous]

gentlemen
my situation is similar to this.
i have double track mainline running from minnaepolis/ st paul to wentachee washington.
wentachee washington has a ten track yard. tracks 1-5 are east bound while tracks 6-10 are west bound. the east end of the trackage in seperate by a double crossover. track 1-5 are powered off breaker no 1 and tacks 6-10 powered off of breaker no 2.
westbound from wentachee to seattle trackage is single track thru 2 helixes all in the mountains.
the trackage to normally run continuous for operation, can be run as continous run for shows.
Are there any special considerations at the double crossover?
the helix

[rrinker]

It sounds like you have this:

Double track ---- yards --- single track through helixes --- back to double track end

If this is the case - all you have to do is gap the crossovers if you want each side of the double track to be powered by a seperate breaker or booster. Also gap the lines coming off the turnout that combines the two tracks into one. You already have each yard individually powered - so the base of the yard ladders must also be gapped. Depending on the length, I would make each of the double track mains a seperate power district or two, and I'd break the single track and helixes up into multiple districts as well.

--Randy

[Esyon]

This was exactly what I needed to know for my setup. Thanks for the great info