To answer the TIU question first. Yes. The TIU is powered by the Lionel 180 watt brick unit. I modified the plug by cutting the factory specialized plug off of the cord. Then I split the cord into two separate wires about 6 inches down. The wire with the writing on it, written in a font I like to call microscopic impossible but white so you can find it, was told to me to be the "red" wire. So using that information I attached a "banana connector" male end to both the red wire and the remaining wire, my guess the black wire, and plugged both of them into the back of the TIU into the Fixed IN 1 ports. That powers the TIU. The red and black wire coming out of the Fixed OUT 1 ports run to a Terminal board and hook to the respective red and black connections there. Finally, a simple red and black wire hooked to location 1 on the board run out to the track and hook in correlation to their colors to the center and outer rail connectors under the fastrack piece I chose to hook them too. My Imperial class CSX ES44AC has started doing it too. It's an MTH Engine as well, but built to run on O36 curve. I guess I need to know after all the back and forth from this thread, was it a bad idea to use the brick to power my layout? Barry always talks about the Transformer I am using. I have a transformer attached to the TIU, but it doesn't power the layout. It powers my grandson's conventional track that is built near the ceiling. I ran the power from the Z1000 through the TIU Variable In 1 port out the Variable 1 OUT port under the carpet to one of the columns and up the wall to the track. I tested it, it works. But my layout track is completely powered by a Lionel 180 Watt brick with an on and off switch.
It's just like having it hooked to a light switch. Flip the switch, power slams the track at its one connection point and filters electricity throughout the layout, weakening as it goes. If the DDA40X is resting on its parking track, it doesn't spontaneously combust. But drive that sucker to the top of the track, the area closest to the connection point or terminal track as we call it, and just as soon as the switch is flipped, on she comes, no remote help.
As for the signal test, I've run one around the track and got what I thought I would get. At first when it leaves the terminal track, it's 10, 10, 10, then it turns the first curve and you start seeing 9's and quickly 8's then it reaches the first switch track and you get 3. After it passes and begins the trip down the bottom of the track you barely get above 5, then you turn for home along the left side of the oval headed back to the terminal top and the signal increases a bit finally reaching 10 again near the top of the oval.
Unless I understood it wrong, and this was told to me and based on what I read, command control is designed to send just the right amount of power to the track to allow the engine to be started and move immediately when directed to by the thumbwheel. It's not supposed to spontaneously power up when it feels electricity flowing through its innards. Opposite a conventional locomotive which takes off like a bat out of heck when the 18 volts cattle prods its butt upon turning on the brick, a command engine, as I understood it, just sits quietly and waits for me to tell it what to do. I sat my grandson's old DT&I switcher on the track, and just as soon as I flipped that switch and power hit the track, it took off like an unguided missile for parts unknown. I immediately turned off the power. Based on how fast it took off, my guess is it was hit with about 18 volts immediately and responded accordingly.
Sorry for the long dissertation, but I am hoping that the more you know about what I am experiencing, the easier it will be for you to help me out. Right now I have one wire set powering the layout. I plan soon to fix that. My fear is the when I do, and the voltage around the ovals increases and my weak spots get better, it won't matter where my engines are sitting, they will all spontaneously combust. My two Lionel's already make a faint telephone ringing sound after they have been shutoff and sitting for about 2 or 3 minutes.