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Just getting into this DCS thing, because eventually I'd like to control all my engines via 1 setup. I've only got 2 DCS capable locomotives (soon to be 3 after I upgrade my Blue Comet Pacific to PS3). I've got several TMCC and several conventional locomotives. No room for a layout currently, but I have a test track running the length of a buffet. Had it powered by a Lionel PH-1, with a Powermaster connected so I could control conventional locomotives via a Cab-1 remote. That recently started acting funky (replaced the remote's batteries, but it's still not sending commands correctly), so since I had a couple of TIUs and a DCS remote awaiting future expansion, figured I'd hook that up.

The TIU works great with my 2 DCS engines. However, when I switch the input and outputs to Variable 1, I'm getting nothing. I have a jumper on the red terminals from Variable in 1 to Fixed in 1 in an attempt to power the TIU. Is a jumper needed on the black terminals too? Just looked at the DCS manual in a PDF file, it clearly shows a wire between the red terminals, and it looks like someone drew a line with a sharpie between the black ones. Hadn't noticed that before, and figured the commons would be connected together. Figured I'd ask here first before I blew anything up.

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It's hard for me to visualize what you're saying about the TIU connections.  Perhaps a photo would be illustrative.

It's possible to control conventional locos with the DCS remote and the TIU's variable channels (if your TIU is fully functional!)  I did it myself a long time ago but from experience I've concluded that it's best to run each type of loco with its native control system: PS2 / PS3 using DCS; TMCC / Legacy using a CAB-2 and Legacy base; and purely conventional locos using a Z4000 or better still, a venerable postwar ZW with appropriate circuit breakers and transient voltage suppression!

It sounds like you already have several hundred dollars invested in the hobby.  No matter how many locos you ultimately collect, you only need ONE of each brand's control system.  Thankfully they're interoperable, if not fully compatible.  I.e., some features will not be available with the competing brand's hardware.  Good postwar transformers have become quite affordable, so my advice is to go that route and avoid using the TIU in variable mode.  Just my $.02, and sorry that I wasn't able to answer your question more specifically.

Please see also this thread:

Last edited by Ted S

I think he's saying he has no wire on the black banana jack on Fixed 1 In.   He was hoping to pick up ground/common if the black banana jacks on fixed 1 and variable 1 were connected internally.

I suspect that's the problem.  A good way to see if the TIU is getting power is to look into the case via the vent holes on the top when you think you are applying power.  There is a red LED in there.  If you never see it light, you have not successfully applied power to the unit.


Run  jumpers between inputs for fixed 1 and variable 1, black to black, red to red. Run Outputs from variable 1 to the track. Then go into the remote and set up variable track 1. You have no voltage b/c it is not set up on variable 1. You have to tell it that. The following is from Barry and his book:

  • Setup TIU Tracks for the variable channels to allow DCS Remote control of the voltage. The is described in The DCS Companion 3rd Edition on page 130, as follows:

Creating TIU Tracks on Variable Channels

TIU Tracks are created to allow the DCS operator to vary the voltage to the tracks through the TIU's Variable Channels. TIU Tracks are created as follows:

• Press the Menu key to enter the DCS menus.

• Scroll the thumbwheel to SYSTEM and press the thumbwheel to select it.

• Scroll the thumbwheel to TRACK SETUP and press the thumbwheel to select it.

• Scroll to ADD TRACK and press the thumbwheel to select it.

• Scroll to ADD TIU TRACK and press the thumbwheel to select it.

• A list of available TIUs is displayed. Use the thumbwheel to scroll to the TIU for which a TIU Track is to be created and press the thumbwheel to select it.

• Use the thumbwheel to scroll to the Variable Channel for which the TIU Track is to be created, either Variable 1 or Variable 2, and press the thumbwheel to select it.

• Use the on-screen keyboard to enter the name of the TIU Track for that Variable Channel. Scroll the thumbwheel to each character in the name and press the thumbwheel to add the character. Press < to delete a character entered in error. Scroll to D on the bottom row, right end of the keyboard to save the track's name and be returned to the TRACK SETUP menu.




There's two ways to power a TIU - either through Fixed 1 or by using an auxillary power supply of the proper specifications fed to the TIU through the Aux port. If you use aux power then you do not have to do anything with the Fixed Inputs - you can just connect to the Variable ports and your TIU should have power. If you feed power only to a Variable port the TIU will not be powered up.

Last edited by Richie C.

Already had the track added to the TIU (took me the longest time to figure out "D" meant "done". I figured it was "delete" and the "<" symbol moved the cursor). The problem was not jumping from the black terminal of Variable 1 to the black terminal of Fixed 1. Could have sworn I originally saw a pic with just the red wire connected. The latest file I found has the "drawn in" black wire. 2020-08-13

Working fine now, thanks for all the help!


Images (1)
  • 2020-08-13

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