Model Train Journal

First off, I have the older TMCC Command system NOT the legacy. Now the fun part!
I have a 2 Rail Weaver Little Joe Electric with factory Railsounds that runs on 2 Rail AC track current. Not DC current:


It operates fine on my test track with TMCC:
https://youtu.be/GxWgMT32sNw
Now the problem. When I set everything up on my 2 Rail loop with 16 VAC my engine doesn’t get the signal from the Command block. It’s just a loop with no switches.
I’m at a loss! Any ideas?
Thanks
Jon

uh...the box says three rail has TMCC. Says 2-rail are DCC ready. So who knows....but...if it was Mikey's BS, I'd say turn the engine around or reverse the wires to the track and try again.

What you are running into is one of the reasons I do not use any of that stuff.

Scalecraft. Uh, the box has a check in the square for : 2 Rail W/Sound. The box does 2 Rail engines are DCC ready, as you need to install DCC. It should be obvious as it sitting on 2 Rail track and in operation in the video with AC voltage. Thanks for your input.

TMCC signal is not actually carried on the rails the way DCC or DCS is. In traditional 3 Rail environment the outer rail(s) are used as one side of the transmitter and the other side is the ground wires of your house. You can get by using a short run (about three feet) of bell wire that is run off the "antenna" lug on the command base and then lay that down flat (aka parallel) to the track. Assuming the command base has the appropriate three prong wall wart transformer it should be using the house wiring as the other half of the antenna. If it doesn't, you should still be able to tap off of pin 5 of the DB-9 connector and then run about three feet of bell wire vertically off of that. That should provide enough signal to get the trains running.

Remember, SC-2 controller have no wheels and no connection to the track at all. I have found these to behave better if you replace the "plate" antenna on the underside of the case with about three feet of fine wire wrapped around the inside of the lower half of the case.

BTW, I'm not sure why this is behaving badly. Carl Tuveson has a bunch of articles on the web site of adapting two rail AF Flying equipment to TMCC https://www.tuveson.com/. You may want to check inside and make sure that the antenna lead in the engine is properly connected and that the Run Program switch is in the correct position. If engine was new/never used, it should be at address 1. If it has been played with, it could be at any number from 1-99 and you may have better luck resetting to factory defaults and then setting the id. Very frustrating with command control to not know the engine id.

BTW, nice looking engine!

Final note. Saw the video on the test track where the engine runs. Is there a separate command base running the test track? If so, there is a chance that the receiver board in the loco is slightly off frequency and is not seeing the TMCC signal from the second base. Normally you don't mess around with the trim pot to adjust this. I'm not sure whether I can find the article on making these adjustments.

Chuck! Thank you for your input!! Perhaps I’m doing the signal wire incorrectly on the loop as opposed to how I set it up on my test track. In the following photo you can see I’ve clipped my signal wire (yellow wire from command base) on the same side with my AC neutral wire. That’s how I set it up in my layout which isn’t working. Are you saying is should just lay 3 feet of command base signal wire next to the track and not attached to the track?

It's worth a shot. You may want to look at the Tuveson site as the flyer system is also two rail and also AC. I KNOW you can run the trains without the track being connected because of experiments I did testing how TMCC signal is propagated.

I actually asked a couple of faculty that specialized in RF about this and one of them responded "This actually works?". The TMCC signal is operating in the reactive (extreme near/H field) part of the signal, unlike almost anything else we encounter with radio transmission. Everyone assumes it works like normal radio control (far/E field) and they try to use E filed fixes for problems that don't exist. By comparison, H field is very, very, very weird.

Chuck!!!! Bless you!!! I think you’ve directed me to at least part or all of the problem! My old command base was missing the wall pack which supplies the base power. I bought an equivalent wall pack (Or so I thought) off eBay. The pack I bought is 2 prong, Lionel instructions specifically state you must use their 3 prong pack that has a house ground prong. Let me see if I can locate one or call Lionel tomorrow if they’re still in stock!
Thank you!
To be continued!

You don't necessarily need a three prong plug. You can run a wire from pin 5 on the command base DB-9 to the ground lug on the outlet cover and that should work as well (aka the screw on the wall cover plate).

Chuck, I just bought a used command base and proper wall pack From eBay for 44 bucks. I can’t use a 9 pin connector because my eventual goal is to tie the TMCC base to my DCS TIU with a tether I purchased. Then enroll the Weaver engine into my my DCS roster. Crazy, I know!
But first things first. I need to get the engine to get a signal with just TMCC first! I’ll check back in when the wall pack arrives with a progress report. In the meantime additional comments are welcome!
PS: linking TMCC to DCS video:
https://youtu.be/lwglG5bwtYY

Good luck and thanks for keeping us posted. The express car mods in the other thread look great!

Success!! The test run on the layout went fine this time!
Chuck, thank you for your input! It turned out the wall pack that powers the Command Base needs to be a 3-prong for a proper house ground.
Video:
https://youtu.be/B1ioHOdg2jQ

Wow, beautiful layout, thanks for posting the YouTube link!

Thanks, Chuck! Excuse the need as I’m laying down one more inner loop.
One more video to share:
https://youtu.be/fUmlsmoakxM

When I get a chance I still need to tether the TMCC to the DCS.

chuck wrote:Wow, beautiful layout, thanks for posting the YouTube link!

Jon had some beautiful scenes on his old 3 rail layout. Some that were used in some advertising.

Jon,
If you still have those scenes or photos, IMHO it would be great to show them again here on MTJ.
A lot has changed here since they were last seen.

Roger, let me see what I can dig up!