To block or not to block track:

[lionelsoni]

When you connect the accessory transformer's common to the train-power transformers' common, you are making only one connection between the accessory circuits and the train circuits.  Current cannot flow between the track supply and the accessory supply through that one common connection.  For that to happen requires at least two connections between the two systems.  So there is no short circuit between transformer voltages, whether in phase or out of phase.   It is as if you took a flashlight and ran a single wire from one end of its battery to the outside rails of your track.  You would not expect either the flashlight or the trains to behave any differently.  There would be no "short circuit" between the flashlight battery and the train transformer.

The control rail is part of the accessory or turnout circuit, not the train circuit.  When the trains wheels roll over it, they and the axle act as a switch that connects the control rail to common.  The train circuit is not involved.  There is still only one point of connection between the two systems, whether the wheels are on the control rail or not.

[3railguy]

Birds

My turnouts are powered with fixed voltage from a second transformer.  This transformer also powers crossing gates controlled by track sections with isolated outside rails.  To me it appeared that both the turnouts and isolated outside rails sparked less when I had the transformers in phase.  They appeared to spark more when the transformers were out of phase.

In this situation is there a reason in phase would spark less and out of phase would spark more?

When out of phase, the cycles are opposing each other. One conductor is negative and the other is posative (cycling back and fourth 60 times a second) so when you touch them together, you create a short. You can put a lamp across the two and it will light up bright. If the conductors are in phase, but the voltages are different, the lamp will see the difference and light up dimly.

I agree that phasing and isolating the center rails only is the way to go. It helps prevent the E units from cycling when crossing blocks. Plus it makes hooking up one TMCC outfit easier.

 

[trainsfan]

I went with Lionelsoni's advice when doing my wiring.  I used what I think was a DPDT switch and I wired the turn-out's power through the same switch that controlled whether block 1 and block 2 were on seperate transformers or the same.  That way the only way a train could go through the turnout was when both blocks were powered by the same transformer.  I remember getting diffferent advise as to whether you could run trains from one block to another block with different transformer so I tried to go the safe way as I didn't want to damage any engines, etc.  Best wishes

[cnw1995]

I so wish I lived near Bob or Kurt so I could pay them to show me this stuff!

Bob and other forumites have given good counsel about this to me in the past. Since I wanted to run more than one train at the same time - and had a plethora of transformers. I followed his suggestions to create an absolute block where each transformer controlled its section of track - where those sections were connected, I used three plastic or fiber pins. I 'phased' the transformers so that a train could move up to the swtich under the control of one transformer - and then into the control of the other - the absolute block also allowed me to 'park' a train with an engine, without affecting the one running on a 'main line.' 

[Birds]

lionelsoni

Comments about the tutorial: [Tutorial in Black, Bob's comments in Blue]

"Transformers that will be used to power accessories that will share the common of the layout will also need to be phase for proper operation."  This is not true.  They don't need to have the same phase, the same waveform, or the same frequency.  For example, I use DC for powering turnouts with no difficulty whatsoever.

 

Bob,

A question about your comments.  The author of the tutorial follows the sentence above with "These would include switches and  isolated rail track sections for triggering accessories."

Is there a benefit to phasing transformers that are powering accessories when those accessories are part of the track-work (turnouts) or controlled by the track sections (isolated outside rails)?

My turnouts are powered with fixed voltage from a second transformer.  This transformer also powers crossing gates controlled by track sections with isolated outside rails.  To me it appeared that both the turnouts and isolated outside rails sparked less when I had the transformers in phase.  They appeared to spark more when the transformers were out of phase.

In this situation is there a reason in phase would spark less and out of phase would spark more?

Many thanks.

(maybe Buss = Kleenex while bus = tissue? )
 

[lionelsoni]

Comments about the tutorial:

Although you can use 16 AWG for this test, the wire you use for your layout should be able to carry the maximum current that the transformer can put out before tripping its circuit breaker.  For the ZWs shown, that is 14 AWG and 15 amperes.

Running between blocks powered in-phase is better than running between blocks powered out-of-phase; but it still creates a short circuit unless you unfailingly set both transformers to the same voltage. 

The two different outlets with different phasing that he mentions can easily be the two of a single duplex outlet, wired from a 3-wire circuit.

It is unlikely that one would want "all 120-volt circuits originated off a one of the two hot lines."  This would halve the current available at 120 volts within the house.

There are more than "a few exceptions" to postwar transformers with common "U" terminals.  Only those with multiple voltage controls use U for the common.

"Transformers that will be used to power accessories that will share the common of the layout will also need to be phase for proper operation."  This is not true.  They don't need to have the same phase, the same waveform, or the same frequency.  For example, I use DC for powering turnouts with no difficulty whatsoever.

("Bus" is correctly spelled with one "s".)

[ADCX Rob]

jokeman48

I am hearing mention about "phasing" as a necessary factor. Can I simply connect a wire from the U post of one zw to the U post of my other ZW to accomplish this task?

Barry

 

Check HERE for an excellent tutorial on phasing ZWs.

Rob

[lionelsoni]

Except for the control rails of turnouts, connect all outside rails together and to the commons of all transformers.  This is the layout common.  (When two turnouts are plugged together, the insulating pins in the control rails might break the connection between the normal outside rails, in which case you will have to wire those outside rails together around the turnouts.)

Insert insulating pins (or just leave gaps) in the center rail at the boundaries of any blocks that you want to create.  Connect the common terminal of an SPDT (not DPST) switch to the center rail of each block.  Connect the other terminals to the two transformer outputs that you want to use.  Center-off switches are a good idea.  If you want to use more than two transformer outputs, there are ways to do that too.

Do not deliberately run from a block powered by one transformer output to a block powered by another transformer output, especially if both outputs come from the same transformer.  This can cause arcing and burn up your wiring and transformer if a train should stall over the gap.  Ignore the advice from those who say that they and everyone they know have run across such gaps all their lives with no problems.  They are either very careful or very lucky.  Or they didn't realize that whatever failed or burned up was caused by the way they did this.

If you use more than one transformer, the outputs should be in phase, to reduce any fireworks if you accidentally run across a block gap that you shouldn't.  Just connecting the commons does not do this.  You may have to reverse one of the line-cord plugs.  When they are in phase, the voltage between similarly-set outputs is minimized; when they are out of phase, it is maximized.

There is no need for a transformer used only for accessories to be in phase with those used to run trains.  If your accessories use the outside track rails as their common return (as the 022 turnouts do), having the accessory transformer out of phase is slightly better.

[jokeman48]

Thanks so much for your quick response. I am a little slow when it comes to deciphering the info. So let me restate and clarify my original question. I have the independent lines set up now. I would like to have the option of having trains travel from one independent line through an  022 switch into the other independent line, thus enabling on occasion, a train to run an extended route for more interest.

I am hearing mention about "phasing" as a necessary factor. Can I simply connect a wire from the U post of one zw to the U post of my other ZW to accomplish this task? Is there a need to do the same for any other transformers I might be using? Should this be necessary for any transformer that will run trains or should it be extended to other transformers even if they won't be running trains but rather accessories, lights, etc.?

I am also not quite clear as to the placement of the fibre pins from your original answer. Could you clarify a bit more?

Barry

 

[kpolak]

wyomingscout

 He said isolate main line 1 from main line 2 by using three fibre pins at each end of line 2.

 If you are using the same transformer or seperate in phase transformers, you only need to isolate the center (+) rail.  The comon (ground) is connected at the transformer across the channels.  (Assuming you are using a Lionel ZW transformer)

wyomingscout

 Then, each main line is controlled by a different transformer, or side of a ZW.  By runnning a wire from the center rail and outer rail of main line one to a DPST switch and out to main line 2, you can turn off the power to main line 2 and throw the DPST switch to power from main line (transformer) 1.  Make sure you don't get out of phase. 

Only the positive center rail needs to be switched.  Connect Transformer post A & D to a DPST switch, and connect the throw of the switch to the center rail of the track block.  You may opt for a center off switches so you can park an engine, turn a block or siding off completly, and still run another engine.

Kurt

[CB&Q]

   well you can use 2 fibre pins one in center rail before the mainline that connects to the left or right switch this isolates the 2 transformers as the middle track is the hot wire. now on the left and right switches put a fibre pin in the 2 short rails. you don't need a toggle switch at all to do this, unless you want to only use one train from other mainline to run on both mainlines then use a toggle switch and run a hot wire from both transformers and select which ever transformer you want to power both mainlines from. that said its actually better if you use both transformers so that no one transformer is having a full load on it as when train goes back to second line then the next one takes over the load. the only thing you have to do is verify that both transformers are in phase with each other. both mainlines can share the same common ground. now when you go to put a train from one mainline to the other its better if both transformers are at same power level so trains don't speed up or slow down going from one loop to the other. hope this helps you both.

[wyomingscout]

Barry,

If I understand your question, I am going to do the same thing.  I talked with my brother-in-law who has an AE degree.  He said isolate main line 1 from main line 2 by using three fibre pins at each end of line 2.  Then, each main line is controlled by a different transformer, or side of a ZW.  By runnning a wire from the center rail and outer rail of main line one to a DPST switch and out to main line 2, you can turn off the power to main line 2 and throw the DPST switch to power from main line (transformer) 1.  Make sure you don't get out of phase.

 Good luck,

Charlie

[jokeman48]

I am thrilled to have the room to finally house my o gauge layout. I have 9 4x8 tables in a horse shoe design so that you can walk in the room and have the center open for those viewing and controlling the operation. I set up independent lines on either side of the tables. When I am finished, I should have 4 or 5 separate train operations, all running separately.

My question, can I have them run independently and also have the option of a pair of switches, right and left that would connect two of the main lines? If this is possible, how do I go about doing the necessary blocking? I have looked at some diagrams in the past and I am not able to follow the specific insulations necessary.

Barry