DCC Power Districts and trains with all wheel pickup (whole train)

[chadbag]

I've been working on adding decoders to my Tomix Hikari Rail Star Shinkansen 700.  As we all know, the Tomix Shinkansen have power connectors between cars so that the whole train picks up power and distributes it across the train.

 

This seems to be a problem with DCC power districts.  If you run DCC with just one big power district (one command station/booster for the whole layout) then this is not a problem.  But if you run your layout split into different "districts" and have a booster on each for power, then you will probably run into a problem with Tomix Shinkansen or other trains that pickup power across the whole train on a single internal power bus (ie, power shared across the whole train).  When you pass the border between power districts the command center / booster needs to compensate for two separate power sources that won't be in synch etc.  Normally it "just works" and you straddle the border for so short a time that the command center/booster can handle it.

 

I've added decoders to the cab cars and one intermediate car plus the motor car so was running a 4 car train today and it would cause the command center to shut down (short detection) as it passed the boundaries between my two power districts.  When I was running 3 cars last night I noticed a little flicker or a very slight hesitation as the train passed the border but it would not trigger the "short detection" and stop the system.  With 4 cars, especially when going slow, it does trigger it.

 

Is my only solution to disable the sharing of power between cars?  Or is there another trick to "fix" this?

[gavino200]

21 minutes ago, chadbag said:

 

Is my only solution to disable the sharing of power between cars?  Or is there another trick to "fix" this?

 

I doubt you'd notice any difference if you removed the connections. I think it's a bit of a gimmick. 

[cteno4]

I disagree, I don’t think its a gimmic at all! The all wheel pickup really does keep out head/taillight flicker and it runs smoothly thru very dirty track! I’ve seen this a lot on the club layout when we get sputters from dirty track with just motor car pickup trains as the day wears on and the Tomix all wheel trains never sputter. At times you realize how dirty the track has gotten after a couple of all wheels are running and you pull out a single car train and it sputters all the way around. Then time to shut down for 10 minutes and scrub track (we put off doing this at shows as long as possible as it annoys the visitors.) they also behave better in the long Shinkansen yards as well where it can be a long stretch of track before a power pickup drop.

 

I hazard antiflicker board also not needed with this.

 

I love the feature! 

 

Jeff

[chadbag]

Whether it's a gimmic or not, it appears to not play friendly with multiple DCC power districts in a layout.

 

I am trying to decide the best way to break the circuit. The tension in the wire holds it in place, so cutting the wire will release that tension (it appears) and you need the wire at the bogie end to transfer power form the wheels into the car.

[katoftw]

Used isolation tape between the bogie springs and the conductor on the non cab and motor cars.

[chadbag]

4 minutes ago, katoftw said:

Used isolation tape between the bogie springs and the conductor on the non cab and motor cars.

 

I still want each car powered (lights etc)

 

[cteno4]

Maybe snip a small piece out of one of the rods going out the coupler arm and just epoxy in place.

 

jeff

[chadbag]

13 minutes ago, cteno4 said:

Maybe snip a small piece out of one of the rods going out the coupler arm and just epoxy in place.

 

 

yeah, something like that.  I was thinking put a drop of CA first, let it harden, then snip both sides.  Not sure how well CA will work with that plastic.  I'll have to experiment.

 

 

[Martijn Meerts]

Hmm.. I wonder if it depends on the system used. The big layouts like Miniatur Wunderland and Miniworld Rotterdam definitely use multiple districts, and they have a lot of current conducting coaches and large trains with multiple locomotives / motor cars.

 

I haven't tested it myself yet, but I was planning on having my yard (and possibly helix) on a separate district. Haven't bought the hardware for it yet though, since I haven't needed it yet.

 

[cteno4]

That may be the rub on those connectors as they may be a delrin type plastic that the usual finger stickers won’t bond well with. They do get some torque onnthemmso something might stick ok without torquing and then pop under some torque.

 

You can also pick up spares of the couplers pretty cheap at hs to experiment on.

 

jeff

[chadbag]

1 hour ago, Martijn Meerts said:

Hmm.. I wonder if it depends on the system used. The big layouts like Miniatur Wunderland and Miniworld Rotterdam definitely use multiple districts, and they have a lot of current conducting coaches and large trains with multiple locomotives / motor cars.

 

 

Do they use DCC?  

 

Large trains are not a problem as long as the cars are isolated.   

[Martijn Meerts]

50 minutes ago, chadbag said:

 

Do they use DCC?  

 

Large trains are not a problem as long as the cars are isolated.   

 

Miniatur Wunderland uses a combination of systems, since they run various track systems as well. Pretty sure they use DCC for a lot of parts, most of their hardware is from Littfinski/

 

Miniworld Rotterdam uses a combination of analog and digital based on the Dinano system.

[gavino200]

How about if you disabled just some of the connections. You could divide the train into three isolated blocks. Front, middle, rear.

[chadbag]

FALSE ALARM

 

My bad.  I re-measured the differential between the tracks between the power districts and the polarity was reversed in one district.  The fact that most of the time (even with 4 cars in a Tomix Shinkansen all-train power set up), when going fast enough, did not trip and it worked (with a hesitation though) is testament to the control center I guess.

 

I'll chalk this one up to my stupidity and also the way the command center and booster are connectors are wired.   The command center has the connector to the track on the back side and the booster on the front side (based on looking at them from the top and how the main writing / labels are oriented) so you would think that if the back is [ Track A -- Track B ] that the booster should be [ Track B -- Track A ] as they are both would be  [Track A -- Track B] when looking at them from the same direction (from behind the connector) as the booster is flipped facing forward.  However it seems that the manufacturer made them both [Track A -- Track B] when looking at them from the "front".

 

Flipping the wires on the booster and now all is hunky dory and it works (only running 3 right now as one of the Tomix cars I had used in the test is opened up to add a light board) but I see no hesitation or light flickering at that junction like I was seeing before.

[Martijn Meerts]

Actually, I did do some reading up on the ECoS and ECoSBoost, and it does mention that you need to check polarity. However, it also mentions you should check the current going to both districts, as a too big gap in current values will also cause a shutdown. This would be mostly applicable when not using equally rated power supplies, or in the case of ESU, having the power supplies not set to the same voltage output.

[chadbag]

Yeah I also checked that both my command center and booster (both Digikeijs) had the same voltage on the input (both have adjustable power supplies) just in case.   

 

I thought I had checked the polarity when I set it up -- when I rewired it for detection blocks in addition I must have not double checked.

 

Thanks for checking.