So, I thought I heard TommyZ mention this in one of his videos on the tube about adding on bricks and putting out lots of additional power for running very large and heavy trains. Is it true that each TIU channel can actually handle up to 30 amps? Holy Moly I thought they were each only capable of 12?

Original Post
DdotCdot posted:

So, I thought I heard TommyZ mention this in one of his videos on the tube about adding on bricks and putting out lots of additional power for running very large and heavy trains. Is it true that each TIU channel can actually handle up to 30 amps? 

30 amps  Now that is my kind of power  I wonder what TommyZ is using for circuit protection since the PSX-AC is good only to 20 amps.

As Marty and John have stated, you can run as much power to the layout as you want (dare to?) without harming the TIU if the TIU is in passive mode.  I use to run 20 amps (now just 15.4 amps) to my layout with no ill effects on my TIU set up in passive mode.

Last edited by CAPPilot

If anyone knows how much the MTH system can take its Tommy. He is not afraid to push the limits. When you are running 10 engines with the smoke wide open and pulling over 100 cars (many with diecast loads)  you are going to be pulling some massive power. Several years back on one of his videos he showed some of the equipment he had fried. 

"Here I try an answer some questions ("and I've had plenty) regarding these "home-made" Meters / "Tap" Transformers. We ran our T.I.U.'s (and do) in "passive". *This Clips a sort-of "seg-way" to another ... (where I'm selling some "stuff"). "

Thanks Joe, I never saw that video. Listening to him in the beginning, it sounds like the two TIU's mounted on the wall are running 30 amp fuses. Then near the end of the video he says there are more TIU's under the table which are passive. I also like the way he mounted the volt and amp meters. It looks like they fit into the dual receptacle covers that have the large rectangular holes for those big light switches. He just turned them horizontally. I don't see a WIU anywhere, unless the video was made before they came out. He never complains about lash up issues, so all his great MU performance must be when 4.2 was being used. Now for his comment on the breakers failing on Lionel 180 watt power supplies. I wish he would have gone into further detail on why they fail. I only ever heard positive thing about the 180's. Last thing, do you understand the use of the big transformers and how their wired in?

Running 30 amps through the TIU is, in a word, stupid!  It will take the variable channels out in a heartbeat, and the traces and chokes for the fixed channels are not rated for that kind of current, so they won't be far behind.

SouthernMike posted:

Several years back on one of his videos he showed some of the equipment he had fried. 

I don't doubt it, if he pulls stunts like that.

I have two separate loops of track , one on the DCS TIU "Fixed 1"  and one on " Fixed 2 " with each having there own z 1000 brick.

I would like to use two switches to be able to go from one loop to the other .  One loop has about 36 feet of track and the other has about 72 feet . I generally have six engines on the main lines.  Would it be OK just to install the two switches and turn the juice on ? 









Yes, BUT: (1) be sure the outputs of the bricks are in phase, and (2) insulate the center rail (not the outsides) at the crossovers.  FYI, I am using 6 TIU channels and all track is interconnected, so any loco can go anywhere at any time.

HEY RJR......really glad to hear this.  I was giving up hope for an expansion.

.........I do artwork and there are 3 of us that changed the lightbulb in my trainroom !!! 

Ah..... phasing the two bricks involves what process ? 

Ah .....insulating the center rail happens at both ends of the switch where the straight rails join it ?   How does the info from the TIU get to the engine if the center rail is taken out ?  Does this have to be set up in passive mode to work ?

Can't  thank you guys enough. This hobby ( or job ) is way more exciting with the communication going on .




Phasing:  power up the layout and both TIU outputs.  No trains started up Take a multimeter set on AC voltmeter.  Place one probe on the red output of FIXED 1 and the other on the red output of FIXED 2.  If you show any voltage > or so, such as around 35+volts, the phasing is wrong.  If close to 0, you're fine.

Insulated section:  I assume both TIU outputs red are connected to the center rail.  If not, they should be.  Place a fiber pin in the center rail of the track connecting the loops.  The DCS signal is fed through the wires from each red output to the center rail of that loop.  The loco doesn't know when it goes from one to another, and neither will you if both are powered on.  You didn't mention what switches or track you are using, so I can't be more specific.

You don't take out the center rail.  You merely put a break in it so current from the center rail in one loop can't get to the center rail of the other.

WOW.....this is really good news .   I looked on different sites and gave up on the idea after reading about not being able to do this.

I'm using all MTH  Realtrack and the switch also.  I have one place that I can make the connection where the tracks are on an even plane but I haven't tried the pieces for the crossover.

I only have one concern . The engine crossing over the break with it's front center rail pickup on one side and the rear pickup on the other side would have a taste of both bricks wouldn't  it ?   I know you have this figured out .  I guess I just don't  understand .🤔🙂

Crossing  the break is not an issue.  I'm not familiar with Realtrack.  There must be something available to insulate the joint.

Thanks for your patience .

It shouldn't  be too hard to create a break in the switch. I'll get the old Dremel out and use a plastic insulator in both switches going to the second loop.

Your explanation was pretty plain and thorough........I guess I need to get more sleep but it's hard to leave the train room😊.



Good afternoon  RJR.......

........I removed all 17 engines from the two tracks.  And all cabooses to do the phase check.  Do i have to remove all the bulbs from the swirches and power lockons ?  All items are MTH .  Probably dumb questions but once in a great while I would have an engine start up when applying the main layout power.

I do have several wires soldered to the track but without a bulb from the TIU TO the track.


I hate to tell you, but you don't have to remove anything from tracks or remove any bulbs.  Unless you're doing a different method of phasing which I didn't describe and which can produce a big spark which could damage engines

Not to worry RJR.😨

Going to do as you described for the phasing.

I won't  do any phasing ( fazing  ?  )  with a fazer from the Starship  Enterprise .🚀😊

I'm surprised it's that high.  Usually close to zero or twice the brick output.  By any chance, are you using controllers between bricks and FIXED inputs?

You gave me an idea RJR.

I unplugged my Lionel Trainmaster Type 1034 that I use for a few houses , An 8 light Lionel floodlght ,a couple small light towers , a lighted bridge and a couple of Pennsy overhead signal bridges and a 3 light track signal some of which I suspected might be hooked into some track lockon.....but...

 I unplugged the Trainmaster 1034 and plugged it in several times now while observing the results of what was getting power. All seemed good with no power from the tracks. 

On the operating devices I have infrared readers .the operating water station and the 5 switches are track powered.   There are MTH lockons.


Just got done crawling around under the layout and bypassed the protector strip and went right to the wall outlet with both bricks.

Voltage now reads 0.07  (   a 700 th hundred of a volt  )  !?!


I would say the transformers are phased.

Be careful using the "fazer."  Misuse could give pointed ears.

A question about passive mode.  If using old style transformers wired in passive mode, is it possible to backfeed the TIU burning out something in it if the shorting current is high enough and the transformer has no quick blow external protection?

The "shorting current" doesn't flow thru the TIU if nothing is connected to the inputs.  Theoretically a giant spark out on the layout could generate a voltage pulse severe enough to blow something, but that would be true active or passive.

Thanks RJR for the phasing info. Now you have paved the way for me to get to work or thinking  ( incubation period ) about getting work done on the RR.

I'm  going to get a short 12 / 3 extension with three sockets to eliminate the surge protection device . It was handy to use the on/off switch but at least with extension cord I'll be able to get power to the front of the layout.

ps.  Thanks for the info on the "  fazer " too.  I don't have a mirror in the trainroom but I have notice that it's harder to get my earmuffs on.  ..........and as RED  GREEN  says " if the wife doesn't find you handsome , at least she should find you handy .


Godspeed RJ

You can find, at places like Lowes or Harbor Freight, extension cord devices that have built-in breakers, switches, and a half dozen or ore outlets.  Having one switch is a great convenience, because if you leave it on, the lights on the layout alert you that you haven't shut everything down. 

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