New member, DCC Computer Question is a free Model Railroad Discussion Forum and photo gallery. We cover all scales and sizes of model railroads. Whether you're a master model railroader or just getting started, you'll find something of interest here.

Hi everyone...

Just joined the other day and wanted to say hello. My father was a huge model railroader for years (got NMRA master modeller in 1980) and I was always in tow at the conventions until I "lost interest" in my early teens (well, more like my "interest" was diverted when I hit high school :) ). Anyway, he passed away this past summer and spending some time in his train room has brought a lot of great memories back. Plus a newly built house with a virgin basement doesn't hurt the situation. :) So I've decided to get back into it.

I have a question regarding computer controlled DCC. I am a electronics and computer geek and decided to go head-long into DCC with a fully computer controlled system - it is based on the TMWDCC system. I am currently using their DOS based control software (which is quite good) and plan on writing a windows version for my own setup. Did anyone else do something similar to this, or are computer-connected people mostly using a DCC system with an interface port? Any problems with doing it this way?



Lazy Daydreamer
Hello Mark,

First of all, WELCOME - or should I say welcome BACK to the hobby!

Sounds like you're perfectly positioned to dive right into it, especially having a wide-open basement and NOT having a fleet of 'legacy' DC locomotives, you can start with a clean slate! (Me, I've got a few dozen leftovers that I still need to put decoders into)

I never heard of TMWDCC before - is that a European system? Anyway, what's really big here in North America is JMRI - that's a Java-based standard for DCC programming which [I believe?] is open-source. If not, here's a link that describes it:

Since I work with 'putors for a living (database admin), I kinda don't want to take my work home with me so I'm letting others have their fun with that. But one of these days I'm sure my own layout will be dispatched via a leftover laptop. :D
Last edited by a moderator:


Hi Mark and Welcome!
I'm like Ken in wondering why you would want to scratch build a DCC control system when so many are already available and at reasonable prices, several less than $200. When I first got into the hobby, I first had visions of me designing some of my own equipment, but soon realized that it would cost more in time and money than to just purchase a manufactured item.

If you want computer software to actually control the trains automatically and their schedules, movements, signals, all through user friendly programming, there are several packages including my favorite being Railroad&Co.

Regardless of the direction you take, I wish you the best in this great hobby and hope to see a lot of your posts.;) :)
Hi guys and thanks for the welcome. There's a great atmosphere in this forum and you guys are inspiring me! I gotta stay away from mtrpls's NYC/Tropicana photos though...that is a dream train IMO - outstanding. :)

CSX: Deciding to get back into it has been a bit of a "journey". I wish my father was still around so we could do some of this stuff together but we were on different ends of the spectrum anyway (he was a logging/Shay guy, I plan to go diesel/long train). I am hoping he still has a few of those old diesels in storage from when I was a kid - that would be great for the memories.

I decided to go the way of scratchbuilt DCC for a few reasons. First and most important, I like building control circuits that are computer controlled. Most of that knowledge is from a home automation system I've built for the house. It started in 1998 and has spanned DOS to XP and GWBASIC to Visual BASIC 6. It can control over 200 outputs and 64 inputs (lights, outlets, window blinds, motion sensors, HVAC, etc). Has I2C/SMBus interfacing, plus a main board of 90+ logic chips. That said, building a computer controlled layout rig was a natural progression. Don't get me wrong, the driver will still drive the train, but I wanted to add some automation to it to make it a little more interesting (like crossings, signals, auto braking in red zones, etc). And the fact it will be a custom program means I can make it do practically anything.

The other reason does base around cost. The controller I've built has approx $25.00 CDN in parts and does full DCC control. The computer is an old P233MMX running Lar's DOS system - when I get the windows version going it will be an old Celeron 900 so in both cases minimal computer cost. And the control options are amazing. Lar's version can map up to 8 throttles to single or multiple engines plus full service programming which can be save to disc as well. This is really what turned me on to DCC.

Another thing these fellas have on the site is homebuilt accesory decoders. Very few parts involved, the most expensive one being the PIC chip at around 6 bucks - maybe 10 bucks in the end. I'm planning to built a few of those for inside the passenger cars (lighting control).

Oh, one other slightly OT question. Back in the day my father used code 70, now I understand code 83 is the new "prototypical" favourite? Was there a reason for the change? And how long has code 83 been around now?



Diesel Detail Freak
Code 83 is a fav because it closely matches 132lbs rail.

As for lighting control, I'd suggest picking up one of Rapido's battery powered lights then making your own copies. They're supposed to be really good.


Mark, a lot of guys still use code 70 on their spurs and sidings, it being more typical to the lighter rails used. As Josh said, code 83 is the more typical for mainlines. I use code 83 throughout my layout, but I'm not overly consumed by being perfectly prototypical.

I do understand your reasons for the more custom DCC system and would like to follow your progress. It sounds very interesting. I don't know if you are familiar with industrial programmable controllers (controls processes, assemblies, robots, utilities, i.e. automation), but having been an instructor and user of them, I had the idea to get an old one and use it on the layout. I still might some day.;) :D
Thanks for the info on the codes. There was a train show the other weekend and I decided to pick up enough rail for the mainlines, and I decided to go Atlas Flex 83. My plan is to also scratch build the turnouts - my father did them before I thought it was even possible and they always worked great.

Rex, this project has already been a learning experience. I built the first control circuit (converts LPT parallel data words to DCC compatible serial TTL) with regular 74LS based chips. It was a proven circuit but it just wasn't timing correctly and was getting a bit frustrating. After wasting a bunch of time on that, I went ahead and took the plunge with PIC chips, programming up a single chip that did the whole job (before the booster). Worked on the first try. Needless to say I'm sold on Microchip's PIC line! This circuit is a snap to build and I found a booster that is rated up at 3 amps continuous for the first main line, probably will build a second and third one for the second main and the yards.

Josh, thanks for the tip on the Rapido stuff. I'll look into that.


Affiliate Disclosure: We may receive a commision from some of the links and ads shown on this website (Learn More Here) is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to - An online railroad bookstore featuring a curated selection of new and used railroad books. Railroad pictorials, railroad history, steam locomotives, passenger trains, modern railroading. Hundreds of titles available, most at discount prices! We also have a video and children's book section. - An online model railroad bookstore featuring a curated selection of new and used books. Layout design, track plans, scenery and structure building, wiring, DCC, Tinplate, Toy Trains, Price Guides and more.