Track Blocks vs. Power Districts

Barry's circular diagram makes sense to me until I superimpose it over my layout. It then makes little sense.

Gasp! I am deeply offended!  

The way to reconcile my diagram with your layout plan is not that difficult. Just look at any complete loop and note where are the blocks. You would have a connection from a terminal block to each track block. Number the blocks of one loop sequentiality, starting with "1".

Let's say that you want 3 power districts, each one fed by a different transformer's terminal block. Designate these three terminal blocks "A", "B" and "C".

Now, make connections as follows:

• From track block "1" to terminal block "A"
• From track block "2" to terminal block "B"
• From track block "3" to terminal block "C"
• From track block "4" to terminal block "A"
• From track block "5" to terminal block "B"
• From track block "6" to terminal block "C"

and so on.

Now, repeat for the second loop and then the third loop.

There are a couple of things to note:

• You don't need 2 TIUs to handle 24 blocks. Even an older TIU will easily handle 12 blocks per channel. Use your Variable Channels, putting them into Fixed Mode if necessary, and you're in good shape as regards 4 channels to handle 24 blocks.
• Power districts can be exceedingly difficult to operate with conventional trains, although it can be done. You'll need to operate all three throttles simultaneously, which is difficult because two would be Z4K Tracks and the third would be a Variable Channel track. Are you certain that you really need power districts?

Barry's circular diagram makes sense to me until I superimpose it over my layout. It then makes little sense.

Barry,

I can see his point as it depends mainly on what consists he plans to run, how many on the same track, passenger cars, lash-ups, and it gets more complicated on larger layouts than a simple loop.

One thing I might suggest is to make sure your Z4000 and 750s are in phase. I founf that my Z4000 and Z1000 transformer were all in phase but not my Z750s. I'm interested in this post because I'm working through some major signal strength issues as I rewire, add and decrease blocks in an attempt to get better and at least functional signal strenght with my one and only PS 3 engine. You might also want to monitor a thread I started on signal strenght of PS2 versus PS3.

Ed

I disagree with the statement that each TIU can handle a total of 24 blocks.  I have 70+ blocks spread over 6 TIU channels.  I see no reason why one TIU couldn't handle the layout pictured above

Since I count 32 blocks, that would imply 1.5 TIUs. Since at last notice you can't buy a half a TIU, I will need two of them.

Regarding power districts... I don't want them, I just thought I had to have them. I won't be double heading any steam engines since none of them have usable couples on their front ends. I may be double heading diesels, but even there most have two or more motors already. Have several that already have four motors either in two powered A units or 4 in one such as the MTH Veranda, and in multiple units such as the MTH Coal Turbine or Centipedes.

In all cases, my Z-4000 ran them all without a hitch. In previous versions, this layout was run via cab-control. Both handles were connected to all sections through the control panel with double pole double throw switches. The other half of the switch turned on red and green pilot lights signifying which side of the Z was powering which block. It worked flawlessly, except I couldn't run anything digitally.

At one time, I had all the blocks fed from the one TIU for a few months.

Since I count 32 blocks, that would imply 1.5 TIUs.

4 channels X 12 blocks = 48 blocks

One TIU should do it!

In previous versions, this layout was run via cab-control. Both handles were connected to all sections through the control panel with double pole double throw switches. The other half of the switch turned on red and green pilot lights signifying which side of the Z was powering which block. It worked flawlessly, except I couldn't run anything digitally.

Your conventional  cab control blocks are still a pretty good way to wire for dcs.

From the tiu output to a terminal block  to the blocks created when you had cab control.It may not be perfect as tooo many short blocks can be a problem but it's a start. maybe use  DPDT center off.

The only difference is that I used a 12 gauge ground loop for the common in the old layouts. Since this will be DCS I am going to have to run equal run star wiring. The DCS book says you don't need to run the common through the DPDT switch, but it should be of similar length. I'm still not convinced that DCS is the way to go. Since I'll be wiring the layout basically like a cab-control design, I may just stay with that, since I'm not sure that I want all operations to be via a hand-held controller. I still like to feel the control levers in my hand to make the trains go. It's also easier for little ones to run the trains via direct transformer control.