DCC Track Short Circuit

[4tonyb]

I am new to model railroading and DCC and before I go any further into this hobby, need some feedback on some basic questions for track wiring for DCC. In other words, I am stuck until this this issue is solved. I presently run four DCC trains on four separate tracks, using Bachman EZ track. Each track has one power connection. Each track is by itself, ie no switches, etc. Or, to over simplify, just four round circles. (Sometime three DCC locomotives and one non DCC locomotive. Also, use Bachman DCC decoder with their 5 amp power boost. Each of the four track power connections are attached from the track to the Bachman booster. All four trains will run for the most part, except once in a while the trains will stop for a second or two then restart by themselves. Also, all four trains MUST run in the same direction. A short circuit occurs if one or two trains runs counterclockwise while the others are running clockwise. The entire layout shuts down and will not restart. (Silly, but it it true) In addition, if I place five lighted passenger cars on the layout, everything shuts down. I need to take the passenger cars off the layout, together with all four locomotives. The layout will not restart until I unplug the DCC decoder and power boost and place the four locomotives back on the track, one at a time. I have now commenced reading model railroading magazines and articles on the internet. Now, the more educated one becomes, the more confused I become. Thus, I have these two basic questions. Questions: (1) Should I be using equipment other than Bachman, such as Digitrax or some other manufacturer? Plan on increasing from present four to eight trains on eight tracks. (2) Am I wiring the track properly? I am reading about track sectional or blocks, etc. but no not understand what this is or how to accomplish it. If I have not asked the correct question please tell me what I need to accomplish to solve this problem. I am starting with a clean sheet of paper, so all options are open. Thanks for the help in advance.

[locoi1sa]

 Welcome

  Try this link to Allan Gartners wiring for DCC.    http://www.wiringfordcc.com/intro2dcc.htm

 Also try Toys Train Exchange.      http://www.tonystrains.com/

 Having problems with MRC products is not new and your experiences with DCC would be better with a major manufacturer like Digitrax, NCE, CVP and Lenz. They all make great systems. Plus you do not have to limit yourself with just one brand of decoder. TCS, Loksound, Soundtraxx, Lenz, Digitrax, and NCE make great decoders. Some functions like ditch lights I like from an NCE decoder and other functions like Auto dimming of the headlight from TCS is a nice function. Mixing decoders in a fleet of locos gives you some programing experience with all the decoder makers.

    Pete

[CPbuff]

Best guess is that the four loops  of track and the four locomotives are exceeding the total amperage put out by the combination of both  the main power supply and the power booster combined which is a fail safe built into most units so that when the amperage surpassed it's limit it shuts down automatically. ( especially in the case of a short circuit. If you have not sectionalized or blocked or zoned your layout your that places all the load on the power supply and booster at once.

DCC Only:

For blocks imagine that your track is cut into 1 foot pieces where both rails do not touch the next piece of track beside it.  Each 1 foot piece has it's own power lead coming off the main wire to power that one foot section. 

Don't block , or sectionallize your layout into one foot pieces!  but make them to fit your situation. On my 18' by 12' HO layout I have 9 separate sections or blocks. I have two main lines running around the outside and I blocked these into North,South,East West and then blocked or sectionalized my yards ontop of those. This makes the trouble shooting much easier.

I am confused by your running of 3 DCC locos and 1 non- DCC loco. The Non-DCC loco should not be run at the same time as the DCC loco's .

 

 

 

[Texas Zepher]

4tonyb

All four trains will run for the most part, except once in a while the trains will stop for a second or two then restart by themselves

This not surprising.  Any time there is a quick short it can hickup every locomotive on the track. Also if the DC  locomotive is running it can suck up all the bandwidth and make things hick up.  Avoid the DC loco.

all four trains MUST run in the same direction. A short circuit occurs if one or two trains runs counterclockwise while the others are running clockwise. The entire layout shuts down and will not restart. (Silly, but it it true)

This one I do not understand at all.  I doodled down a diagram and there is no way I have been able to create (draw) a short circuit that is depenent on the direction of the trains. 

if I place five lighted passenger cars on the layout, everything shuts down. I need to take the passenger cars off the layout, together with all four locomotives. The layout will not restart until I unplug the DCC decoder and power boost and place the four locomotives back on the track, one at a time.

What about four lighted passenger cars?  Have you measured the current draw of the passenger cars?  If each one is pulling 1 amp of power this is not a surprise, other than the system not resetting itself.  Unfortunately I am not familiar with the Bachmann DCC unit, but I do know it is very basic.

Questions: (1) Should I be using equipment other than Bachman, such as Digitrax or some other manufacturer?

Normally I would say, no, but you have something really strange going on and the Bachmann seems to be the wild card in the mix.

 

Plan on increasing from present four to eight trains on eight tracks. (2) Am I wiring the track properly?

Sounds like they are wired properly to me.

I am reading about track sectional or blocks, etc. but no not understand what this is or how to accomplish it.

I belive this would be what is normally called power districts.  It is simply a way to isolate one section of the railroad from another.  In your case I think there would be eight power districts.  One for each loop.   This would isolate power consumption and short circuits to a single loop.  What happens is that each power district gets its own power supply and booster, or this can also be done with some power district isolation units such as the Digitrax PM42.

 

please tell me what I need to accomplish to solve this problem. I am starting with a clean sheet of paper, so all options are open.

I think I would start with a single loop and get it working flawlessly with one loco.  Then add a second, third, etc up to all  eight locos & passenger cars.  That will demonstrate if the problem is a loading issue. Then add the other loops one at a time.

[4tonyb]

Pete, your references were quite informative. I am becoming more comfortable, except I am still confused on what is meant by "more track feeder drops".

[4tonyb]

Thank you for the quick responses. I will ditch the DC locomotive. Will also look into the Digitrax PM42.

[mfm37]

4tonyb

I am still confused on what is meant by "more track feeder drops".

 

Extra feeders applies to the number of wires you have feeding the DCC to each loop. At present you indicated that it is being "fed" to each loop at one point. Additional feed points will decrease the total resistance on the layout. Add a set of feeders directly opposite the first set and the resistance will be cut in half. That's good for the DCC signal. Add more feeders around the loop and reduce it further. All of the feeders can be connected together at one point, then a single larger wire can connect the feeders to the DCC booster. This is what is called a "bus".

A simple check to see if more feeders are needed is the "quarter test" . Simply place a coin or some piece of metal across both rails with the booster turned on. It should detect the short circuit and shut down immediately. By immediately; I mean start counting and if you get past 1, that' s too long. Add feeders to fix. The first place to check would be exactly half way around from the point that your feeder wires are attached. If the circuit breaker trips there, try a few more spots around the loop.

 I'm not sure what system you have but the problem you decribe appears to be a case of exceeding the output current of your DCC system. Mention brand and model numbers we can be more informative .

Martin Myers

[4tonyb]

Martin.....thank you very much. Now I understand what and how to add more track feeder drops. I am assuming that it is ok to solder all the wires together before attaching to the DCC Booster. I am using the Bachmann EZ Command Control Center, Item # 44902, together with the BachmannE-Z Command® 5 amp Power Booster. One would not think a amp shortage would occur with three DCC locomotives, one DC locomotive and five lighted passenger cars. I will implement your suggestions and add more track feeder drops. In addition, other have suggest to use #12 gauge wire and eliminate the DC locomotive. Will do those also. I will bring up one loop at a time until a short occur, if any. If the above does not work, maybe I need to switch to Digitrax products.

[mfm37]

4tonyb

I am assuming that it is ok to solder all the wires together before attaching to the DCC Booster.

Yes, solder them to the 12 ga wire. 14ga should actually be large enough but 12 won't hurt. Use a color code to keep the wires from the same rail connected together. I use red for outside rail, black for inside rail.

One would not think a amp shortage would occur with three DCC locomotives, one DC locomotive and five lighted passenger cars.

5 amps should be plenty of power for your needs but check those lighted passenger cars. Incandescent lamps will eat some power. The DC loco won't draw any more current than it would with a DCC decoder. The motor and lights use the current and they won't change by installing a decoder. Running analog will slow the system response  but does not use more current.

Will do those also. I will bring up one loop at a time until a short occur, if any. If the above does not work, maybe I need to switch to Digitrax products.

 

Good idea to take it in smaller chunks. Easier to keep things staright and definitely simpler to troubleshoot. Switching systems won't help because a short circuit is a short circuit. We set our modular NTRAK layouts up and apply DC first. If no problems are found, we hook up the DCC.

Martin Myers

[4tonyb]

Martin.....Thanks again. You been a great help. I now feel confident the issues can be fixed.