#990 Legacy Control System

I honestly don’t have an exact answer for you. I would think just the one is fine, on our clubs layouts where atlas or Ross/GarGraves was used we alternated witch outside rail got the AC neutral drop. American Flyer typically works fine with only one rail but I know problems can pop up. If n tubular or fastrack the outside rails are already jumper’d. Someone smarter than me should pop in but I think the best way is to try it and see if you start having issues with signal or not.

Except where you've isolated a section of outside rail for non-derailing, track occupancy, or other signaling application, your layout should be wired such that all the outside rails are connected to the transformer 'common'.

If that's the case the command base is thereby connected to all your outside rails.

In two rail, larger and more complex layouts work better with the Legacy signal on both rails. This is done with .1 microfarad 50V ceramic capacitors. They are tiny and inexpensive. Using these capacitors all segments of the rails can carry the Legacy signal, even the isolated sections where necessary for good Legacy signal reception. One caution, I do not have DCS so I do not know if these would degrade the DCS signal.

If both outside rails are connected together internally (such as with Fastrack) or are jumpered together, then connection of the Legacy base to only one outside rail should be sufficient.

Midnight,

    At both clubs I belonged to we hooked the legacy wire to our transformers ground outlets. We used both the latest ZW from Lionel and the MTH Z4000. You only have to connect the legacy wire to one of the ground outlets as they are common.

JohnB

@AmFlyer posted:

In two rail, larger and more complex layouts work better with the Legacy signal on both rails. This is done with .1 microfarad 50V ceramic capacitors. They are tiny and inexpensive. Using these capacitors all segments of the rails can carry the Legacy signal, even the isolated sections where necessary for good Legacy signal reception. One caution, I do not have DCS so I do not know if these would degrade the DCS signal.

They would nuke the DCS signal, that would be a point of contention if you did have DCS!  .1uf at 3.27mhz results in a capacitive reactance of around half an ohm.  So, that would be like putting a 1/2 ohm resistor across the DCS signal output!  Needless to say, the TIU DCS signal would be seriously impacted by multiple .1uf capacitors across the outputs!

Thanks John. I had a hunch that would be the result but I did not know the DCS frequency, that's why I added the caution. My layout has 17 capacitors, six are across the outputs of the six reverse loop controllers. There would be no DCS signal at all!

The DCS signal would be negative!

Really appreciate the feedback I'm receiving from all of you. Many thanks!

I have Atlas O track - not sure if both outside rails are connected in the track.  But my layout is small - U-shape with an overall footprint of 10x12.

One of my outside rails does contain some insulated joiners because of my Atlas signals. But the other rail has none.  So I'm thinking I'll try just connecting to that outside rail and see how it goes...

Is there an Atlas O track expert out there who knows if the 2 outer rails are connected internally within the track itself..?

No, Atlas track has totally insulated rails.

John B, I like your suggestion!  It is simpler than soldering the legacy line to the outer rail (my track is ballasted so using a joiner is out of the question).

And that worked fine without any issues?

Thx, Gunrunner, for the quick response!

FWIW, it should work fine with one rail.  Our modular club layout does not have both rails connected, and Legacy/TMCC works flawlessly.

Great!  Thx again!  I'll keep you all posted on the results...

@Midnight Express posted:

John B, I like your suggestion!  It is simpler than soldering the legacy line to the outer rail (my track is ballasted so using a joiner is out of the question).

And that worked fine without any issues?

Midnight,

      We never had any issues at either club. I hooked thee TMCC system on my home layout the same way again no problems.

JohnB

Sounds good, John!

Thanks again!!