MTH DCS into 2 Rail Scale

Stephen

This is my Sunset Great Northern O-8 Mikado doubleheaded with an MTH S-2 Northern.  The O-8 just came out of the Hikel Layouts and Trains backshop after conversion to ProtoSound 2.  With the upgrade the Mikado now speed matches beautifully with other Proto2 or Proto3 equipped steam, electric and diesel locomotives for consisting or running as a manned helper.

O scale ProtoSound 3 equipped locomotives will run on conventional AC or DC power, DCS with AC or DC power or on DCC.  The choice is yours.  That also makes it pretty simple to take your locomotive to the layout of a friend or a club. 

If you are running conventional DC be advised that, like many other dual mode sound decoder equipped locomotives, Proto 3 requires clean DC and the full NMRA recommended 16 volts available on the rails to be able to run at full speed.  In conventional AC or DC mode Proto 2 and 3 locomotives use the track voltage as the speed command.  They start moving at 8 volts and you will want to have at least a little more than 12 volts available for mainline speeds.

To read about Proto 3 installations I recommend this thread by DCS Beta Tester and repair tech Marty Fitzhenery.

https://ogrforum.com/t...-upgrade-information

OGR forum member John Sethian operates a very nice 2 Rail layout with DCS.  He would be my go to guy for info on practical lessons learned inusing DCS for 2 rail scale Layouts.

Ed Rappe

why not contact tcs wow they have a 5 amp decoder for O Scale coming out this month. you should be able to program any whistle in it.

I concur.

The only caveat with DCS is reverse loops for two reasons:

• Proto-2 engines are polarity-sensitive -- i.e., they pick up the data off the hot side. Rear-facing diesels in a consist would have to have to polarity reversed via a small DPDT switch. Proto-3 engines don't have this issue, so I'd strongly advise going with a Proto-3 upgrade when they become available.
• DCS superimposes the data packets onto the track voltage, where DCC creates digital square wave which IS the data packets, so using electronic polarity reversers for wyes and reverse loops may be problematic. The work-around is to go "old school" and use DPDT relays to flip the polarity.

Fortunately, if you go with Proto-3, it also contains a DCC decoder (engages/disengaged via a jumper on the board or a switch) so you could convert the layout to DCC and retain the MTH sounds. I've run a Proto-3 engine (GE Hybrid) on a DCC layout and it worked great -- sound, lights, smoke and the "chase lights".

I have yet to see a 2-rail layout with a wye or reversing loop.  I know they exist, but suspect they are somewhat rare.

Forgot to mention the potential issue with a turntable depending on how the bridge is wired.

Stephen

As Ed pointed out, my 2 rail layout exclusively operates on DCS.  I have both PS 2 and PS3 engines. I have converted (or have had my LHS convert) a number of engines from a variety of manufacturers to PS 2. I have never done a PS 3 conversion, but I do have an MTH 7 with PS 3 from the factory.

Against that background, I fully concur with what Ted and Matt said.  If the N&W J will be your lone DCS engine, then put PS3 in it and wire your layout for DCC. It will be totally compatable with DCC.  I did a review of the MTH F7 for OST, and found that it ran just fine on a friends DCC layout.  All CVs worked fine, and it could be readily programmed.  You will also keep control over all the sounds and conrrol of the lights, smoke volume, etc.  PS 3 also eliminates the reversing loop issue.  

If you want to run straight AC, a lot of the secondary sounds will not be available.  The engine will make a chuffing sound, and you can activate the whistle and the bell via a suitably equipped transformer. The engine sound volume can be controlled with a potentiometer in the loco. The smoke can be toggled on or off by means of a switch in the tender.  But you won't have control over anything elset.

If you want to run straight DC, pay attention to what Ted said about voltage requirements, and note you will not be able to activate bell or whistle. 

If you want to run solely DCS, then you have to pay attention to your track wiring.  Its straightforward once you understand the underlying principal that you need to be sure your locos get its commands via one, and only one, path.

If you want to run a combination of DCS and DCC, they are not compatible, so you will have to designate one track for one and one for another.  And maybe a switch for flexibility.  I think you'd be a bit of a pioneer here.

Good luck, and e-mail me if you have any questions

By the way, my understanding is MTH will be using recordings from the newly refurbished 611 for its model.  Those sounds should be fairly awesome.  If they can figure out how to block out the crowd noise 

Ok, wyes might be, but reversing loops are rare?  Yikes!  Pretty sure I have an optional one at the one end of my layout,

Bob2.  reverse loops are commonly used as staging tracks on the ends of "dogbone" pattern model railroads.  The concept nicely supports prototype operations where continuous loop running in not desired.  My current railroad has 5 hidden reverse  loops at each end of a long multi track mainline run.  Several good sized  O scale 2 rail railroads in the MD/DC/VA area feature staging track reverse loops.  See John Armstrong's Track Planning for Realistic Operation for info on how they can be employed.  

Ed Rappe

Yeah - the dogbone is my dream setup.  It might not happen - the only space I have that big is dedicated to wing recovering.  I probably have seen a reversing loop - maybe at Stivers' or Bergmann's place - but most of the O Scale I see is round and round, kinda like mine.

Martin has the luxury of very tight radius, which makes reversing loops easy.  But what is the big deal?  Why is having a reversing loop so important that it drives folks to 3-rail?  Yes, I know there are DPDT switches that fix the polarity, and I also know that some fancy electronics can do it, but I just do not think they should be the driver of a track plan or the selection of command control technique.

I really don't care - I will never need a reversing loop.  I need more display shelves!  Preferably covered when we start spraying dope.

I have two turntables -- one at each end of my point-to-loop to point layout.  They are electrically the same as reverse loops.  The layout is DCC.  I use PSX-AR auto reversers and operation is flawless.  

Worrying about dogbone polarity wiring can be a thing of the past if one chooses to go DCC.

Having spent many years with TMCC, Legacy, DCS and now DCC, I find DCC the simplest and most reliable of the bunch for all sorts of reasons.  Simple and reliable is good.

I run MTH DCS in two rail. I also run it in G scale, which is two rail.

I've been watching this post.

I don't have any real wiring issues. There are limits to each system, or rules that need to be followed for it to work.

 I much prefer DCS to DCC. I would have invested much more money with DCC. I personally feel that DCS is just an organized version of DCC.

E-Joe.  How do you deal with reverse loops and turntables (polarities) when running 2 rail and DCS? Is there a way to auto switch polarities like with DCC 2 rail?

Austin Bill

I have a wye, a reversing loop and 2 turn tables on my TWO rail layout.   You do them the same way in 2 rail O as in any other 2 rail scale such as HO or N or S or G.   You can control polarity manually with DPDT switches, or you can use they automatic reversing devices with DCC and some may be available for straight DC.  

Reversing loops and wyes are NOT rare in scale model railroading and not in O scale either.   Our local O scale club has a bunch of them.

My personal preference would be to stick with DCC for your whistle and contact TCS/WOW.    I prefer non-proprietary open systems to closed proprietary ones.  

Because of the way DCS transmits its data packets, physical polarity switching as if you were using DC is probably the best way to handle this (i.e., relays and sensors). Azatrax (http://www.azatrax.com) has optical sensors of various types and (more importantly) implementation diagrams and parts lists to handle polarity issues.

Bob2, Here is a Frog Juicer equipped combination wye/reverse 13'6" X 29' staging loop on a DCC pike:

 4 1/2" right of way centerline

I have 2 reverse loops on my layout. They are no problem for me.