Bill,
I've done a lot of research on DCC and how it works. For proper DCC "ALL" you track should be live. You can't rely on frog switching to provide power to certain parts of the track. This is because DCC operations can include sound, lights etc, and you would want your engines sitting there idling in the yards, with lights on etc maybe when not in use. The reason for heaftier wiring is that all power to the layout is provided through one transformer/circuit and all loco's requirements are provided through that single circuit. ie. you may run 2 -3 controllers now with each controller powering "blocks" or one for the yards, and one for the mainline and the other for the second mainline etc.
With DCC there is a constant 12 V DC across the track. The voltage does not vary. It's the digital signals the DCC systems places on a "sub frequency" (if I can call it that) that the decoders utilise to power everything. Sorta like having a mini-controller in each loco.
Analogue controllers are really designed a provide enough power to run a single loco. Try running 3 - 4 - or five loco's through the one controller, and see how hot it gets. Too much draw on the power. You will need to wire the track to cater for 12 V DC at about 5 amps. The wire you are using to wire the track should be sufficient for that. Just make sure you have power to ALL parts of the track. You can use a "block" system in the meantime, then install DCC, and then just switch all you blocks on all the time. Most DCC systems provide 12V DC at about 5 AMPS. If this is insufficient for the entire layout (running more than 5 - 6 locos, including stationary ones, with lights on, sound etc) then you will need a "booster", If you have "blocked" your layout, adding a booster would be simple. Just divide your sections in two, and connect the "booster" to half of the blocks. IF you have wired you layout as a single circuit, then adding a booster could be a little more difficult.
With the booster, you will have (say) 5 amps to one half the layout, and 5 amps to the other half. The digital signal from the DCC box will be superimposed over both sections.
Most DCC decoders are capable of drawing up to 1 AMP from the tracks. (sound, lights on/off, motor etc) also stationary decoders can be used to switch points, signals, requiring one 1 circuit of AC to all the point motors etc, instead of individual circuits.
A properly wired analogue system should take DCC easily, however if you start with DCC in the first place, then wiring a layout is much simpler, but there is no going back. ( no need for blocks, just run a single 12v DC circuit under the layout board that follows the track, and pop it up onto the track where necessary. Maybe two section (blocks) if you intend to have lots of loco's. (and require a booster). DCC also provides for auto reverse/loops as well, without having a double pole switch.
This help a little?
TOOT!
DCC is an excellent method, however is pricy!!!
[This message has been edited by Woodie (edited 07-05-2001).]