Hi zackesch88,
For what you want to do the NCE decoder you are looking at is a good choice. The Hogwarts engine in particular should work out quite well because the gear ratio is very short and you should end up with pretty decent motor control. The gear ratio on the Williams GP-9 is much taller, so your slow speed performance will probably be so-so.
Your bigger challange is going be some of the operating accessory cars. Most of them use a chassis ground for the operating mechanism and will not be easily converted to control by an accessory decoder. To make things easier on your self you'll probably want to stick with some of the newer operating cars by MTH which use DC motor drives. For instance, the MTH operating ice reefers, side dump cars, and signalman cabooses all have DC can motors that are isolated from the chassis and are easy to convert to DCC The Lionel operating crane is also straight forward to convert electrically, but it is a fairly complicated conversion because of the number of circuits (4 drive motors, 5 solenoids, and one lighting circuit).
One of the big reasons you don't see a lot of folks converting 3-rail O equipment to DCC is because of the technical difficulties. There are some very good technical reasons why DCC never took off in 3-rail O. What you are planning sounds pretty modest in size, so you souldn't have to break the bank to get a high enough amperage DCC system. However, you will have issues signal quality. Three rail switches have several spots that are prone to arcing. FasTrack switch are pretty good in this regard, but don't be surprised if you have some trouble. You will also need to open up each FasTrack switch and remove the wires that connect the outside rails to the switch motor. Removing the track power jumper only isolates the "hot" side from the center rail. Be sure to keep your pickup rollers well lubricated. It's not uncommon for rollers to arc to the axle rivet where you can't see it. Any cars with constant voltage lighting circuits, such as Atlas and Lionel cabooses, will need to go dark or get an accessory decoder.
Hope that helps.
You probably should post this on the O Scale Railroading magazine forums, perhaps under the "3-rail Scale" forum.
As you note, many recent Lionel engines run on AC power, but have DC can motors. The internal wiring converts the AC to DC. In theory it should be possible to remove the electronics, reverse unit and all that and wire thing up to go from track power thru a DCC decoder to the motor.
http://ogrforum.ogaugerr.com/forums
I think that you can do what you are thinking of with no problems. As far as the decoders go, it doesn't make any difference if you use O scale decoders or G scale decoders. The main difference between the two are the physical size and the current that is availble for the motor. So as long as the G scale decoder will fit in the space you have, it will work with your O sclae locomotives. You could even add sound only decoders to your locomotives as well, and these could be HO.
I have also connected two motors to one decoder in HO, on a Bowser T1 loco, and it worked just fine. Again, the current draw of the motor(s) is what matters. I connected the motors in parallel. The ideal situation would be if each motor drew one amp, and the decoder was designed for two amps, all would be well. (1+1=2) The current of each motor is added together and should not be more than the motor output of the decoder can handle.
As far as the smoke units are concerned, you should test them and see what current they draw or use when operating. Then call the manufacturer of the decoder you want to use and see if the decoder can handle the current on one of the aux outputs.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
You might want to post your questions also on the CTT Forum (Classic Toy Trains) Lot of O-scalers there. Easy way to get there, bottom black bar at bottom of this page, click on Classic Toy Trains.
Frank
OK, sounds good. I haven't run any O since I sold my inherited Lionel stuff about 1970 and got into HO, so was just wondering about that.
Mike Lehman
Urbana, IL
Both locos I own are using can motors, and can motors are dc.On the boards that come installed from the factory, there is a full wave bridge rectifier that converts the sin wave of ac into a dc current.
I know Lionel was AC, not sure about what wonky stuff MTH does. I'd think the Lionel motors would need swapped out, since they are AC. DCC is designed to drive DC motors, so not sure it would work with Lionel?
http://www.ncedcc.com/component/virtuemart/?page=shop.product_details&flypage=flypage.tpl&product_id=52&category_id=14
this is the decoder I have in mind.
Before things get heated, I understand that converting 3 rail to DCC will gut out the soundboard and be replaced with the new decoder. Sound to me is a Non issue, I personally don't care for it and would rather create ambient, environmental sound. The reason I'm thinking about doing this is I DO NOT like the fact that MTH and Lionel cannot play nicely like the rest of the model railroading world when it comes do digital command by following NMRA digital standards. I WILL NOT buy two separate systems to run trains or the MTH work around to run Legacy/tmcc on DCS. In all honesty, this is a massive black eye to 3 rail O IMHO. I am an HO scale modeler dabbling in O scale. I like the size of O, and the flexibility "tight radius" and fun rail cars/operating accessories that 3 rail O has to offer. I guess I would be classified as a hybrid high rail modeler with toy train tendencies. I plan on keeping HO for the club that im at now and keep O for at home. Now into the meat and taters. My modeling goals is to model an industrial park, much in the spirit of lance Midheim, with 2-3 operators max. Now, I would like to keep things familiar with my fellow club members and stick with Digitrax "what we use at the club," and I also put a chunk of change into my DT 402. Another reason is would also like to be able to use JMRI for programming, along with slow operations. As I mentioned earlier, I'm well aware that the existing sound board will need to be gutted. I would like to note, I only own 2 locos "Hogwarts express "Lionel" and a Williams by Bachmann GP-9. Both have can motors, the Hogwarts express has one, gp-9 has 2. Now, with the gp-9 having 2 motors, how will that be installed into the decoder? Also, I would like to have the option if possible to use smoke machines in the locos. I am aware that running that directly will cook the decoder, so my thought was to use a relay, use the low voltage to trip the relay as a function and use track power to power the smoke unit. If all else fails, I guess i can use a rechargeable battery. When it comes to decoders, I understand Digitrax and NCE, sadly not TCS makes O scale decoders, can a G scale be used too? As it comes to Fastrack switches, the switch machine will not be run off of track power, but powered separately. For my last thought, are there any members who has done this? There are examples on the web, but not a whole lot of 'em.