MTH TIU

Is this layout all new ?  If not. Did it ever work properly ?

It sounds like you have 2 ovals connected with a crossover. Sounds like your engines are starting in conventional. One TIU is fine. Just make sure you have power going into Fixed 1 or your TIU will not power up and supply the DCS signal. Also make sure the DCS signal is turned on in the remote. Your first objective should be to get the engines to come up silent.  If you are throwing a toggle switch to power up the layout. Engines can miss the DCS signal and power up. When they are sitting there with sounds on. If you hit Start Up. What happens ?

I’m assuming these engines are added already in the remote. Did you use the layout to add them ?

Size does matter. On a small layout 1 channel could be sufficient. You may need multiple feeds to create blocks though. But they give you 4 to use. I would seperate your 2 loops and put them on separate channels. You can use your crossover or insulating pins to make the layout 2 separate blocks.

You can have multiple engines on the same track or block. The only issue maybe a Lionel engine effecting the DCS signal.

Daniel,

As you can see by the prior response, your initial inquiry doesn't provide enough info to give you a decent answer.  Whenever you have a problem with power and a related operating item, it helps to fully describe the power source, how the power is routed to the operating item, and a full description of the operating item.  Here's an example:

Power source:

Type of transformer (MTH Z4000, Lionel ZW, etc.) connected to MTH TIU (Rev ?) which connects to layout

Power routing:

List out all your connections and / or all intentional separations (usually insulating pins or other track separations).  As a suggestion here, a wiring diagram might be worth a million words.

Operating equipment:

MTH Locomotive (20-xxxx-1) operating under (PS, PS2 or PS3) acquired new (or secondhand).

Finally, it would help if you fully describe what tests you have already performed to try and diagnose the issue.  For example, did you try separating the loops to see if the engines would run on only one or the other loop?  Did you try just running with only one engine on one loop?  Did you try taking any of the locomotives to a local hobby shop to see if they ran there?  If you haven't tried any of these, maybe you need to find and read some literature (lots of free stuff to read on the internet) about how your model trains are supposed to work.

Chuck

Thank you  to all who replied:  I have three ovals, two of the ovals powered by one lock on and the other two ovals separate with the other TIU power source. The two ovalls are connected by  an interchange track, Atlas O gauge switches used to switch from both tracks. I have one MTH engine on the inside track and two (lashed up ) engines on the other track. I have one TIU with power to one fixed from a ZW transformer going to the outside disc onnected track (three ovals) and  the other fixed from an MTH power block. I used one TIU channel to power the outside oval and one TIU channel to power the the two inside ovals connected with the interchange track. When I removed the one MTH engine from the third or inside oval, the locomoitve on the second oval was fine, Except I could not get  the bell or whitstle to blow from the DCS remote. I am working on  this . My question, should I get another TIU unit to power the third track OR, insulate the two tracks getting power from the TIU, using two separate lock ons from one TIU. Do insulators have any bearing on issues like these?  I have reset the engines, cancelled and added them  from the DCS system and reset the TIU When you reset and engine, what is the difference between a factory and feature reset?  I hope this explains better my issues and clarifies my challenges. I have no hobby shops close as the one I use for repairs is 150 miles away.

Thank to all who respond.

Well, I still don't see how much track is on each oval. Here's my opinions.

You don't need another TIU yet unless the ovals are very big.

Powering the TIU is best using the auxiliary input, so it stays powered when channel 1 is not.

You have to have each track separated from each other with insulators and have each oval broken in at least one spot. If the signal is weak each oval will need more breaks and more power drops to each.

Each channel of a TIU can only feed so many engines, and feet of track and joints of tracks. Track joints can be losses of power and/or signal.

Wire size is also important. #14 copper stranded for runs is the best.

Older TIUs can benefit from a light bulb to soak the excess signal. Newer version "L" TIUs don't need this.

There's a lot of info on wiring in Barry's book on the MTH website.

You still have two unused TIU channels that can be used, so you shouldn’t need another TIU. It still sounds like the engines are missing the watchdog signal.

  Joe and John have some great points. I found out early on when getting DCS up and running. The Track Signal test is your best friend.
I wouldn’t look at the big picture of getting all 3 loops operating. Just work on one loop at a time using 1 channel for each loop. Put in insulators in the center rail where needed at your crossover. Your variable channels can be set for fixed voltage. So you have 4 that are available. Do a signal test and report back with what you get for a number. When you achieve pretty much a 10 throughout the 1st loop. Then move onto the others..

As Joe mentioned. Many variables involved. From gauge wire used to the size of the loop itself. Plus the many track joints that come into play. It all starts with a Signal Test to see what you are up against.

Sorry, but I can't answer any of your latest questions.  However, it still might help others if we knew exactly which TIU version you were using (normally marked on the product or the product box (Rev H? Rev L?) and exactly which engines you were trying to control with DCS (tell us the model numbers (20-xxxx-x or 30-xxxxx) and give us the box descriptions (e.g. PRR USRA 0-6-0)).

Chuck

They appear to be working now, but I am gioing to insualte the two inside tracks and connect the power to one TIU fixed port. My TIO and DCS are about 15- years old or so and have worked  fine until changed my layout from two to three tracks and enlarged it.

You shouldn't need another TIU, not even for a basement sized layout in an average home. Definitely not for three ovals, assuming they're concentric and layout area under 500 square feet or so.

The amount of track a TIU can support is more based on how it's wired and how many track sections there are. But this really only matters at the upper limits of the TIU which I doubt you're near.

It's a good idea to leave the ovals "open" where the sections furthest from the lock-on are insulated from one another, especially if they are large ovals. But this not essential.

You might have a weak TIU channel. If you have a lot of derailments, or like to put cars or engines on the track while it's energized (anything that may cause sparks or arcing) this can cause some issues with the TIU circuitry over time.

If it acts up again, you could set one of your variable channels to fixed mode and try using that.