When running both systems, is there a specific advantage to running the Legacy signal "through" the TIU rather than just connecting the base directly to the track ?
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No, AAMOF, running it through the TIU is not advised, connect it directly to the track.
I have mine connected directly to the track, but the reason I ask is I remember this advice from a previous thread:
1. Connect wire from Command Base to "Black" fixed Output of TIU.
The black "output" post is not running through the TIU, it's going directly to the track.
Right .. that's why I put the word "through" in quotes in the original post.
So, now re-phrasing, is there an advantage to connect the base to the black output post of the TIU or just directly to the track or does it not make a difference in performance ?
I can think of no reason that it would make a difference in the performance of either Legacy or DCS.
Sounds good to me - thanks. 
Richie C. posted:Right .. that's why I put the word "through" in quotes in the original post.
So, now re-phrasing, is there an advantage to connect the base to the black output post of the TIU or just directly to the track or does it not make a difference in performance ?
Should work fine either way. I connected the base after the TIU common output post on my layout but that's because it was easier to wire. The connection is electrically the same along the entire length of the wire.
Lou1985 posted:Richie C. posted:Right .. that's why I put the word "through" in quotes in the original post.
So, now re-phrasing, is there an advantage to connect the base to the black output post of the TIU or just directly to the track or does it not make a difference in performance ?
Should work fine either way. I connected the base after the TIU common output post on my layout but that's because it was easier to wire. The connection is electrically the same along the entire length of the wire.
Because of the location of my base, it was easier for me to wire directly to the track. I just wanted to make sure there was no performance disadvantage to doing it that way.
Just to follow up - here's my thinking (probably faulty):
If I connect directly to the track, there's only the one connection for the Legacy signal to carry through a few hundred feet of track.
If I connect to the black output wire of the TIU, it goes to a distribution panel and star wiring to 15 power drops along the layout, so the Legacy signal has 15 connection points along my layout and that extra signal propagation might ease any potential Legacy signal strength or ground plane issues.
Does that make sense ? 
Not really, you should connect the Legacy signal to one location to avoid multi-path signal distortion. There is nothing to be gained to connecting it to the TIU, at least IMO.
Makes sense, although I always understood that multi-path signal distortion was more of an issue with DCS than Legacy because of the way the DCS data packets were transmitted and that's why Barry (and others) always recommended dividing the layout into blocks.
It is a far greater issue with DCS as the frequency is higher and the wavelength is shorter. However, that's not to say it can't happen to TMCC, so why tempt fate? Since it works fine at huge layouts with one connection, I'd just connect one place.
Agreed … don't forget to set aside some time at the end of January (25/26) to make the Amherst Railway Show in W. Springfield, MA.
