Lionel Switches being thrown by MTH remote

Gonna need more information.

Using a TIU+ AIU????

Using a TIU+ serial cable to a TMCC or Legacy command base?

Either way, the obvious thing would be isolation. Unplug the serial connection between TIU and TMCC. This implies you are using command switches and again, you are getting the triggering signal as a command from DCS crossing over the serial cable to the TMCC/Legacy base.

Or unplug the TIU to AIU interface. If the AIU isn't connected- then DCS cannot trigger a switch- if that's how your switches are controlled.

@Vernon Barry posted:

Gonna need more information.

Using a TIU+ AIU????

Using a TIU+ serial cable to a TMCC or Legacy command base?

Either way, the obvious thing would be isolation. Unplug the serial connection between TIU and TMCC. This implies you are using command switches and again, you are getting the triggering signal as a command from DCS crossing over the serial cable to the TMCC/Legacy base.

Or unplug the TIU to AIU interface. If the AIU isn't connected- then DCS cannot trigger a switch- if that's how your switches are controlled.

A TIU, yes we do have one. No AIU as we don't use any accessories that are requiring one. @Allan Loczy can share more details on the wiring of it is needed.

Also, other causes I've seen:

We are talking about Fastrack switches, so command or just remote they both still have these basic issues out of the box:

#1 Internal folded tab construction. These folded tabs to the internal bus bar plates are not just on center rail, but also outer rails and the anti-derailing sensing sections. Over time these connections loosen, and if outer rail is intermittent, you can get false throws and other issues. The fix is open every switch and solder all the folded tab connections- as long term failure prevention before the problem creeps up.

#2 The screw terminal connections, the inside soldered wire connections are known to point upwards (when the switch is upside down and you are looking at the internals) towards the metal back sheet. There is no internal insulation on the metal back, and so those connections can short in some cases- sometimes between various terminals, to the metal back.

Again, just from the very opening start of this topic- imagine someone taking a bunch of fastrack switches out of the box, not doing any of this preventive corrections, wiring them up, screwing them down to modular layout table. Run trains over that for a while, disassemble that layout and transport it frequently- Yes, 210% I would expect that outer rail continuity depending on the folded tabs and fastrack connection pins loosening, I'd see all kinds of intermittent problems, ground loops, stray currents, voltage drops, and worse, those uninsulated metal backs being slowly pressed over time right into the solder points and wiring of the screw terminals.

Again, I wouldn't be surprised to find out is has nothing, absolutely nothing to do with DCS, and everything with the known issues I just presented about fastrack switches.

@Nathan B posted:

A TIU, yes we do have one. No AIU as we don't use any accessories that are requiring one. @Allan Loczy can share more details on the wiring of it is needed. Yes, you better believe it is needed- the current explanation is not cutting it.

@Nathan B posted:

Our module group (the MOD Squad in NE Ohio) uses FastTrack and remote switches in our yard section. One of our last shows we ran into this weird issue that our switches are being thrown by the DCS system.

I'm getting that you don't know the wiring, but here is the problem- based on all the info posted this far to this topic- there is no connection between DCS and these switches- NONE. DCS signal is embedded in the power. Lionel TMCC/Legacy is an RF signal.

If there is no AIU, then the only other connection possible is a serial connection  between the TIU and TMCC/Legacy base

or

Again, the more we get into this, the conclusion that switches were randomly being switched by DCS is highly unlikely.

Nathan, What troubleshooting was performed to determine that the TIU is the cause? Have you disconnected the TIU from the layout to see if this odd behavior stops?

There's got to be an explanation for this.

  When we run the modular setup without the TIU connected it works fine. When we plug the TIU back into the setup it starts having random switch throws. We have had 3 different TIU’s during these operations and continue to have these random switching appear. We connected with another group in York and one of the other switches on their section would throw at random. When pushing start up engine on the MTH controller one of the switches flipped. Repeat it and it doesn’t happen, maybe an hour later randomly on engine start up it would do it again and we have had it happen on other buttons but not consistently.

What we have tried

• Removing the TIU – no DCS, no problems with switches
• Most of these switches are new
• These switches are wired with accessary power
• • The club we connected to had it running with track power when it flipped
• Tried assigning a number to the switches to see if the receiver wouldn’t cross a signal that maybe be close:
• • No change – still have problems
  • Also if they are all on default #1 you would think they would all throw together
• Removed the tmcc radio receiver from the fastrack switch track – unplugged it from the board- no switch throwing problems
• tried to repeat the switch throwing when pushing a mth button and it doesn’t seem to be every time but an hour later we push a button and the switch throws in sync. Haven’t observed it happening when no one is pressing buttons. (more difficult when in a group operating environment)
• we can try running for a few hours with the TIU included but not using any DCS controllers for a few hours and see if it would throw.

I do believe there is some interference between the MTH controller and the TIU with our setup as we get high readings from the train on signal but the controller works better tethered. Odd question is can the tmcc radio receiver on the switches pick up a signal from the mth controller. We have not tried moving the power supplies away from the TIU as its all setup to be close for wiring reasons. Below attached is the wiring simple wiring diagram we used. No AIU.

I don't know what the internal DCS Remote and TIU logic does prior to sending TMCC signals to the serial port connected to the Lionel base, but from the description of the symptoms it is likely that bogus commands, or a noisy signal, are being sent from remote via the TIU to the serial port.  If you can setup a notebook running the LCS WiFi Monitor program, you can see switch commands on the log output.

Do the symptoms persist if the TIU is swapped?

Do the symptoms persist if the DCS remote is swapped?  (Lionel's Cab handhelds generate the TMCC commands, not the base.  If MTH uses the same approach to format TMCC commands, then a different DCS remote or a software refresh may resolve the problem).

Are the TIU and all DCS remotes loaded with the current software?

Have you tried a different serial cable between the TIU and the Lionel base?