Need some help with Kato Unitrack

[comeng84]

Hello

 

This may seem like a rather "newbie" question(s), but I have some questions with powering a multi-track, multi-controller setup DC setup.

 

Right.. on to it then.

 

I have recently been inspired to start planning and building up a more permanent setup with the whole shebang. I have started to buy up Kato Unitrack, Scenic Plates and Buildings with a rough idea in my head. The idea is to have two lines running in parallel with crossovers, and spurs coming off to a depot, and possibly an elevated section.

 

But one thing has been on my brain that I simply have no knowledge on: the crossovers.

 

In my current spectacular single track loop, I have used Unitrack switches before, but as they are on a single track, its no problem. My question is how do you manage a crossover on dual controlled tracks?. I will be using EP481-15L's to create the crossover.

 

Do you use insulators between them? Do you leave them uninsulated? Can you run a train from one controller to another without frying the electronics?

 

Hope this makes sense

 

Thanks for your help

[westfalen]

If you have a seperate controller on each track you will need insulated joiners between them. If the controllers are set for the same direction and speed you can run trains between them. At a later stage you might want to break the layout up into smaller electrical block sections and wire each block to the controllers through DPDT switches so each controller can control any section of track, but that can be for later.

[nickhp]

Is that correct?  I thought the turnouts were route-selective on power, so only the direction the turnout is set to is powered.  So... if both are set "straight" and powered bu separate controllers, there should be no issue.  If one turnout is set to diverging and the other straight, there should again be no power issue though you will have a nasty mess train-wise on your hands!  Finally, if BOTH turnouts are set to the diverging route, only ONE controller should be used to avoid conflicting power inputs.  Am I missing something here?

[KenS]

Let's call your tracks "left" and "right", and your controllers (or power packs as I prefer to call them) "A" and "B".  The simple approach, which many of us have used, would be to wire A to right and B to left (or vice versa).  Now if you use power-routing turnouts you could in theory set things up so that the two didn't interfere without needing to use insulators, but in practice it's not going to work.

 

First, Kato's #4 switches (the 481 radius ones) aren't "power routing" in the sense that both rails are dead when the turnout is switched away from that direction. Look closely at the switch: the outer rail on each side has no gap, and thus is always live.  Only the inner ("frog") rail is turned off.  And to make matters worse, the #4 isn't always power routing; that can be set by moving a screw on the bottom (and the labels are backwards from what most people expect, so it's confusing to get it to work the way you want.  I have diagrams of how the #4 works on my site.

 

Second, human nature pretty much guarantees you'll get it wrong at some point and connect both packs with opposite polarities which the switches are set to cross. The results should just be to trip the circuit breaker on one or both packs, but it's really a good idea to avoid that just in case the breaker doesn't trip and you burn out the packs.

 

Now if you insulate the rails where "left" and "right" meet, each side is fully independent of the other no matter what you do.  To move a train across, if you set both packs to the same direction and speed, the voltages across the insulator will be roughly identical. As the train crosses, the two packs will short together through the wheel (and possibly though the two wheel assemblies if both are wired) but at worst you've got something like +5V shorting to +4.9V on one rail, and the reverse on the other.  Power packs can take that for the short time it takes for a train to cross with no problems. But left connected for a long time, the unintentional current flow between them could cause problems.

 

You can of course still get the packs reversed even using the insulated rails (I did, more than once actually), but when that happens your moving train stops dead as it shorts the packs when crossing, and you have a really obvious indication that something is wrong and you need to turn them both off NOW.  Despite doing that several times, both packs and the trains involved came through just fine. I did have to reset the little red circuit-breaker button on the back of my packs each time though.

 

I used Kato's double-track with the WX310 crossover (which has built-in insulation as described above) with two Kato packs, and crossed trains between them for several years with no trouble, despite the occasional short, before I disassembled that layout.

 

Now another, more complex, method is to wire each track to an A/B switch (DPDT, center-off) connected to the two packs, as westfalen mentioned. Set them both to "A" and pack A controls both tracks, allowing a train to move from one to the other without any shorting at all. Insulators are still needed here, due to the switches not being fully power routing. Permanent layouts are often wired like this (it's called "block wiring"), but it's more complex to do, so Unitrack layouts, which are often more temporary in nature, often don't get wired this way.  Despite my "temporary" layout remaining set up for two years, I never bothered with this kind of wiring, even though I'd done it before on a more permanent HO flex-track layout.