I read through most of the FAQ and posts on multiple transformers and isolating rails, but I need someone to clear up some gray area for me…
I have a layout design with 3 ovals (O-72, O-54, and O-42), and all are connected together with O-42 switches. Since each switch is back to back, I think I will have to isolate each center rail from one another, requiring power for the center trail to come from the loop that the switch is closest to. The actual switch power will be from an accessory post. Track power will be from the track. The track below the 1, 2, and 3, are solid through. The white text box erased some of the track.
In the perfect world i would run one MTH Z-1000 per loop. From what I read, this isn’t going to happen safely. I don’t play on running TMCC or DCS anytime soon.
I have to be able to control the speed of the trains on each loop. I would love to be able to also send bell and whistle signals to each train as well. I have wired up a strip of bridge rectifiers that does a good job of dropping voltage. Bob Nelson has preached until he is blue in the face about the voltage issues between blocks being dangerous, and I’m not sure if powering different blocks from one transformer using taps from the bridge rectifier fixes this problem, since there is still a voltage difference. I think most of what he was saying was using multiple transformers. I guess I need some clarification here.
I was thinking of using one larger power transformer sized for 3 trains, and use the bridge rectifer and some rotory switches to adjust voltages between loops/blocks. All track power will come from one source, but it will have to be a big source. I don’t mind bypassing the traditional controller and putting in my own knobs for throttle and
Wes,
I have often wondered this myself. Since Bob preaches about not using two tranformers on two seperate loops and then ‘connecting’ those loops with switches. I have seen large layouts with multiple ZWs and when you look at the track plans there are switches connecting the different main lines. So if this is a NO NO how is it done without damaging the trains or transformers?
I need to know because I am getting ready to start construction on my big layout and want to be able to move trains from the main level to the second level and so forth, and could have as many as 2 trains running on each level at a time.
I use several interconnecting loops with different ZW transformers with no problem. Several thoughts before you “switch the switch!”. The loops on my layout have insulated center rails where the switches go from one loop to another and use constant power from a different source for the switch machines (coils). The MOST important factor is the transformers are PHASED together. Once properly phased, I paint one side of the A/C plug so if they ever get disconnected for service, they can be re-installed with the proper phasing. My brother had a Maklin A/C layout once upon a time using two transformers plugged in individually to a un-common powere source. He couldn’t figure out why SOMETIMES the train would go across the insulated gap between the two transformers, and sometimes it wouldn’t. It just stopped or did the “Hippy-Hippy-Shake!”. I reversed the A/C plug (turned it around) on one of the transformers and then plugged them BOTH onto a power strip. Problem solved!
Maybe we should break down each problem slowly so I can follow -
It sounds like the ZW (and maybe a couple other Lionel transformers) can easily be phased. What about the MTH transformers though? It doesn’t sound like the outputs can really be tied together like the ZW. They only have a red and a black terminal coming out of the controller. The plug that goes from the power brick to the wall is polorized, but I don’t know if just getting the input wall power to the brick is enough to call it Phased or not. If its as simple as getting the input power phased, then good! There are many posts like the one that AFML just posted that states that fixing the input voltage to the brick pretty much solves the shuttering problems, and I assume the arcing too?
I think beyond getting the phase correct so the trains run like they are supposed to, Bob
The only hazards I know of associated with your desire to run a seperate Z-1000 on each loop would be; 1. out of phase transformers. and 2. voltage deltas while trains cross your insulated blocks.
is easy you’ve shown you’re able to properly “Phase” your transformers.
Not sure how easy this is, but assuming you have volt meters on each transformer you could manually equalize the voltages on the two/three loops involved before trains cross them. I would want blocks which could be powered down on which to park trains currently occupying these loops.
This get’s you past problem 1. above but your still left with problem 2.
You mean Santa didn’t bring you a TMCC set this year? You sound precariously close to deserving one…maybe even a legacy?
I know…you have all these great PW locos that you want to run right? That’s my problem too.
Yea, most of my stuff is MTH. I just recently added a Kline with dual motor A and B units. It’s so fast even at 8 volts…so matching up voltages between blocks won’t work.
I would probably go DCS if I even went with command mode.
Hopefully Bob will chime in here and give you more info. I’m pretty sure it’s okay to use multiple phased transformers as long as you closely match voltages when crossing.
but for another take I’ve been running for two years now this way with my new ZW. I even have one brick dedicated for the uphill incline and another for the down. A big jump in voltage for the climb obviously and I still havent’ encountered a problem. I’ve checked the rollers and the trains and the new zw seems fine. Maybe modern circuitry can handle this kind of running.
I also use rotaries so I can take any block on my layout and assign it to any one of my 4 zw channels. I love this flexiblity. I believe this is call “cab control”.
Cab Control - Learned something new. It looks like some of the HO guys use cab control a lot too. They don’t seem to be worried about the voltage differences between blocks either. Maybe it’s a DC thing. I wasn’t planning on being able to send any of my transformers to any block on my layout, but now that I read about it, it seems like a good idea. There are so many ways to do it, really. I like the cab control better actually. If you have 5 different transformers, you can dial in the 6 position switch to whatever transformer that you want to use. That’s a great way to regain control of horn and bell functions. I put all the trains on one transformer except the one I want to control. Great idea actually!
What are the dangers if I can sync lets say 4 or 5 MTH Z-1000s input the the bricks? Just the voltage differences between blocks? I would believe so after all of your talking.
I am so glad I started this post. We never talk about Cab Control.
Here’s cab control in action. Check it out. You can see my rotary setup at the end of the video although it’s tough to see. I added a control panel pic here too.
I have three interconnected loops. First I dedicate a channel or transformer if you will to a train. Then I choose the path of that train and set all the necessary trackage/blocks to that transformer position on the rotary. My rotaries are 5 positions that include an off position. My spurs work the same way.
You guys have been busy! What a lot of posts to work through! It’s really nice to see that someone has been reading my sermons.
First, the single-transformer-with-diodes approach that you proposed, Wes, is quite safe. Since the diodes are completely passive, during whatever time you are connected to two diode taps, the higher-voltage (shorter) string supplies the current. The important thing is that neither string has any way to force current into the other block’s supply, the way two transformer outputs would try to. The same situation exists with the old-fashioned rheostat control scheme.
One way to have individual whistle-bell control with the diode scheme is to build one of the diode-type whistle controls to go with each diode speed control. This is two strings of simple diodes, with the strings connected in parallel but with opposite polarity. A normally-open switch (pushbutton) shorts out all but one of the diodes in each string to unbalance the waveform and blow-ring the whistle-bell.
Brent, the way people get away with that kind of running is by doing a consistently good job of matching voltage, waveform, and phase and by not lingering with pickups straddling the gap. Even so, they do run the risk of creating high-voltage spikes from the stray output inductance of the transformers. Pre-modern trains don’t mind these at all.
Here’s the deal with voltage, phase, and waveform: DC voltage is constant and unchanging; so all you need to describe it is one number, its value in volts. AC is changing. AC, the way it comes into our houses and the way it used to come out of our transformers, is varying as the sine of phase. This is very like the sinusoidal motion of a steam-locomotive crosshead as the drivers rotate. The angle of the driver crank is the phase; and the position of the crosshead is the voltage, with one extreme being positive and the other extreme being negative.&nbs
You guys have been busy! What a lot of posts to work through! It’s really nice to see that someone has been reading my sermons.
Bob, I told You that I’m NOT THE ONLY ONE who appreciates Your sage advice on things electrical. Your advice is well RESPECTED and APPRECIATED by MANY here on the forums. Just taking another chance to say THANK YOU VERY MUCH, from all of us.
Yup, Bob has helped me in many ways already. Thanks Bob!
So does anyone know if the MTH Z-4000 splits the 400 watts output evenly to the outputs? I know that there is a 10V 3A fixed, a 14V 3A fixed, and two variable outputs for the trains. It would be great info to know.
Thanks,
Wes
I too have been an avid reader [and header] of Bob’s guidance. I am constructing a large [for me] layout. 30 x 20, multiple levels, 4 loops, activity yards [a place where acccessory activity occurs] and two storage yards under the tabletop - tracks where engines, self-powered units like plows etc. and consists slumber and await the call to come up to the table top - most is out of immediate sight. Each of the storage yard tracks has its own power district, so the lights are off until the power is on. each of the yard tracks connects to a run-around loop that takes the consist up to the tabletop via a helix - actually 2 two tracks - one up and one down on each helix.
There is one starting point on the layout that is a ‘dead-end’ where a new entry is placed or one removed, but from every other spot on the table-top or in the storage-yards or activity-yards you can go to any other loop, passing siding or level on the layout. I run conventional PW and more modern TMCC. There are a couple of steep [greater than 3.5%] grades, a mixture of track and switches - tubular 0-27 and GG with Ross/GG switches thruout - close to 80. There are two intersections, one using 4 90degree crossings and another with 4 45degree crossings - yes they needed help to get the powering correct.
I power with both PW ZWs and 180 Watt PoHo devices thru TPC controllers. I use a lot of blocks - better - power districts where the center rail has a plastic pin and powered on/off using BPCs. In a lot of cases the center rail on 2 of the 3 sides has a plastic pin to give me the district separation that is needed. [PS: toothpicks work well for this]
I operate the switches with both Pushbutton and TMCC equipment [SCs and ASCs] I have three Control Panels - one with 10 SPST toggles that is solely dedicated to operating an Atlas Turntable operation in one of the activity yards. I have 2 Lionel Transfer tables - with extensions. The passeng
