The grandkids want to help with a new layout.I have tons of stuff from older layout's I have done over the years.All were dual cab controlled not digital.I have many older engine's.I like the dual cab type layouts and have all the controllers parts ect.Would you start a new layout not going with the new Digital control.The layout will be 20 ft by 7 ft area.It seems most are going digital now.But having so many older DC engines that I would love to use.I know they can be converted but that is quite a of work.I was going to keep the layout simple for the kids to run.2 mains and a few branches and a yard.Also where is a good place to get wire online for the layout.Well I look forward to coming aboard and thanks for any help.

going digital is not an either or proposition. it is possible to wire your layout for cab control (i do) and use a dcc controller as one of the cabs. to do this you can't use common rail wiring, all blocks must be double insulated to keep the dc and dcc isolated from each other.

it is also possible to run dc locomotives on digitrax systems, unmodified, using address 0. i also do this all the time. dc locomotives on dcc are noisy and some claim you will burn out motors. i never have. you can also park your non dcc locomtives in a siding and turn off the block switch just like on dc.

the main difference in the wiring is that for dcc you should use a larger wire size. i use 18 guage which some claim is too small, but i find anything larger than that i have trouble soldering to the rail as the wire no linger fits neatly between the head and base of the rail. you'll also want to add more than one set of feeders per block.

In My Humble Opinion
If you already have lots of DC goods, might as well stick with DC.
The fact you are already familiar with what to do and how to do with cab control  is a big plus in your favor.
Plus it will save you some big $$$.

Wire on-line? I'm certain this place will have any type of wire you want.

http://www.radioshack.com/home/index.jsp

or any on-line trains and hobby shop should have wire.

two other Points to ponder
DCC locos will work on a DC system, no problems.
DC Locos do not like DCC power levels which are a bit higher and will burn out DC locos motors if you are not carefull.

I probably wouldn't build a non-DCC layout again.  Too much, most even, of the currently for sale merchandise is DCC already.  Plus, there are some very real and desirable operational advantages to DCC.  Too, you might find that it's easier for a youngster to operate the trains in DCC because they don't have to be continually throwing switches to make sure the right cab has control of the block they are using.

However, you have a lot of DC models.  That makes the decision harder.  But, some of them probably aren't the best runers anyway, and it's really not that hard to convert most locos as long as you can isolate the motor from both rails.  Sometimes that means a new motor, sometimes not.  Actually, the new motor may be the easiest and cheapest at times. 

As for running DC locos on DCC, I wouldn't do that very often.  There are many reports of damage, but not everyone has trouble.  I would never leave a DC model sitting on an operating DCC track.  That's just asking for a failure. 

Cheap wire?  You might find it anywhere.  I suggest going through a current model railroading magazine and checking several of the advertisers' on-line prices.

I know you'll enjoy model railroading with the little ones.  I consider myself so lucky to be ble to do that with one of my grandsons.

here is a good source for wire
http://www.allelectronics.com/

Having recently made the switch from DC to DCC, here are some observations:

1. Operationing a DCC layout is a lot easier.  I must admit I went with the EZ Command system. It does have some limitations but it is push a button and turn the throttle. So you have the choice of a simple DCC controller. This could be very easy for youngsters. It has some other limitations but on my small 4 x 7 layout it works great.  I added one remote controller, too.

2. It is a lot easier to wire, other than running heavier gauge dual feeder wires. Which would help a DC layout too. You really don't need any switches to control the tracks.

3. I had several DC locomotives and have converted 6 now. It gets easier each time but they all seem to be challenging trying to squeeze all of the extra wire back in the small HO narrow shells I like. I have purchased 4 Bachmann DCC locomotives and they are not too expensive. By the way there are lots of on line resources to help with conversions.

4.  I did cheat I wired it up so I can switch back and forth between DC and DCC  but am finding I would rather run the DCC locomotives because how easy it is to control them.

All in all I think DCC is the way to go.
Hope this helps

My brothers layout was for years a duel cab DC layout. With the addition of 1 switch, the layout is now DC or DCC depending on how the switch is thrown. He still has all the blocks and associated switches on his control panel.
We have found over the years that most switches stay in one position. Only passing sidings, yard tracks and reverse sections get switched regularly.

Run a two track main line with isolated 2 ovals each with its own Power supply
Run branches and sidings off each one
That way you don't need blocks just switches for the sidings
With a 7 foot width you can easily have independent sidings etc for each oval

Thanks guys for all your help.Lots of good ideas.I think I will go dual cab for now.But use larger wire for the runs so it could easy be used for DCC later.I just have to many nice Engine that I want to use that are DC.I allready have a control panel that can be used for any lay out.I made one on my last lay out with all the turnout switches running across the top and all the block controls running down one side.I just replace the black tape of the track design and use Number decals for where the turnouts and block are.But I will get a DCC down the road.Now just getting stared and picking a layout plan.My room is 25 long by 13.I was thinking of a 20 by 7 table in the middle but now looking at a U shape layout 40in wide on each leg of U 15ft long and top of U 40in.I will have to stick with 18in radius turns.But I do not use large trains like passengers cars.Mostly coal ' Tankers 'Box.I have done mountain layouts withs lots of hydrocal but will mostly use a midwest theme.Thanks BOB

I recommend that if you have the room, go with 22" radius as your minimum on the main lines 
I went with Panels that were 2' x 4' in size and doubled them on the ends. This gave me room for 22" radius curves and 2' wide on the rest of the layout. I kept it low ( 32" ) for easy reach as I'm handicapped. The inside curve on the left is 19 1/2" radius which would have been bigger if I had the room. All other curves are 22" and 24" radius. I use code 83 Atlas track. Here is what it looks like. It is set against the right wall and the left loop has a 2' isle next to it. All areas of the layout are accessible from both sides except the 2' wide areas next to the wall, they are easy to reach.

That looks like a nice layout.I misspoke about the radius.I am looking at a point to point layout that uses 24 radius.It is a U shape plan that will run up against the walls  all way around my room leaving a nice area in the center.The plan is out of a old 101 track plans by Linn Westcott of the Iron ridge & Mayville.It would give me nice background of drywall to use for sky and hills and such to paint.It is a good size point to point.I have tons of atlas code 100 nickle silver flex allready.But I am still debating.I know some like to watch trains go around in circles but I really love point tp point.It will be 50ft run from the furthest  town to the other town track wise.But I have a few weeks before i get the room ready for bench work.

If your room is 13' wide, you could put a couple of 4' x 4' sections on each end to give you the option of continuous running or point to point. like this

Yes I have thought about that.Yes I have room to make the turns to come back.I look at your pics on your post.Very nice work.I might use some of your plan to make the ends larger so I can make a complete loop.It is nice to just let the trains run while just sitting back and injoying a pint of Ale .

This is big enough to double track and give it a really long, long run. Would you like to see what I mean, I could whip up a quick plan of the mainline

Thanks yes by all means.I am Bob.Glad to meet you