MTH DCS Old Layout Install

Your set up is very similar to mine, which was built before DCS and which I wasn't about to rewire, although my ground is a #12 looped around the layout and back to the transformers.  I also have 2 postwar ZWs & a Z4000. 

You do not have to change the wiring, assuming that you have the hot (center rail) broken into blocks with one individual feed per block.  The hot should be no smaller than 14-gauge for good electrical distribution.

I suggest you do what I did:  just place the TIUs in line between transfomrers outlets and wherever you have them going.  In fact, I don't have any connections to any black TIU inputs, but all TIU black outputs are connected together and to the ground loop.

RJR, Thanks for the reply.  What you stated made me happy.  I will proceed in the manner that you did.  One question though.  I know what a block is. But what is a block when it comes to DCS.  I use gargraves track.  My layout is about 15 x 30.  I have feeds throughout the layout for about each 5 or 6  sections of gargraves 36 inch track.  Two loops.  One Z4000 handle controls the outside track the other handle controls the inside track.  None of the track is isolated except for sidings or sections where I can park a train.  Each of these are controlled through a toggle switch.  Is a "DCS block" isolated, ie. center rail pin removed or rail cut through?  If so, I need to cut, isolate my loops into blocks fed by one feed of power.  Right?  Thanks again.

Rick, Barry's analysis is correct.  My layour was built & wired for conventional.  Every bit of the track on this 39'x16' L-shaped layout is part of a toggle-switched block, so that I could stop any convenntional loco anywhere (using the toggle switch) without affecting other locos on that circuit.

Based on my experience with DCS, I am still of the opinion that every bit of a layout should be in a toggled block.  It eases locting derailments, programming locos, parking locos, and determining where light bulbs would help signal strength (supposedly not an issue with Type L TIUs).

If you have feeds every 6 sections, all you need is a moto-tool to slice the center rail & you're set.

Rick,

   RJR and Barry are giving you the correct skinny do as they advise and your layout will run correctly.

PCRR/Dave