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DCC friendly switches. Confused !!!!!

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  • Member since
    November 2002
  • From: Colorado
  • 4,075 posts
Posted by fwright on Tuesday, November 15, 2011 11:32 AM

trainnut1250

You actually have several issues here:

The first is that the Shinoharas are power routing.  This means that they rely on contact between the point rail and the stock rail to power the turnout through the frog.  This set up gets sketchy over time as the turnout ages and begins to create dead zones as the points don't conduct electricity through the turnout.  I have a buddy with over 100 HOn3 Power routing shinoharas and he spends lots of time cleaning contact points to keep the turnouts conducting power correctly.  There are several fixes for this issue.

The usual fix is to add a feeder for the frog and power it through a separate contact on the switch machine (or manual throw).  The frog feeder becomes a parallel path for powering the points/closure rail/frog and the selected turnout path.  The points are powered through the hinges if they don't make perfect contact with the stock rail. 

The second issue is the backs of wheels shorting against the points of the opposite polarity as they pass.  The same buddy didn't modify a single turnout when he converted to DCC and has had no problems with these types of shorts.  He runs lots of older brass as well as the latest Blackstone offerings.

What many folks don't realize is that the same possibility for the wheels shorting out happens in DC.  In larger HO standard gauge, the locomotive/train usually powers through the momentary short, the circuit breaker doesn't trip, and the short goes unnoticed.  With the much smaller HOn3 engines and the shorter, lighter trains, the odds of powering through the momentary back of the wheel short even when using DC are significantly decreased.  And as Guy said, the Shinoharas in HOn3 have a reputation for not having the wheels short out.  They rarely need modifying for use in DCC.

Advice:  If the number of turnouts is small, I would buy Litco, Cream city or Railway Engineering turnouts that are already wired to be DCC friendly and not use the Shinoharas at all.  Absent that, I would take the time to modify the Shinoharas, not because of the shorting issue, but mainly to make your life simpler when it comes to continuity issues as the turnouts age. 

Be very careful of what you are buying if you go down this road.  Litco and Cream City use Fast Tracks designs and templates, which are usually hingeless points.  Stephen Hatch at Railway Engineering also uses hingeless points.  Unless the closure rail is gapped, both point rails are tied electrically to the frog and you electrically have the same situation as a Shinohara.  The examples of HOn3 Litco turnouts I have seen do not have this gap.  They may have changed since.  Railway Engineering will put in the gaps at your request, and I believe Cream City does also.

HOn3 is small enough that continuity is an issue, those points are tiny and you want the most reliable powering scheme to make operating fun.  Nothing like having to tap the loco to get it to run past a dead spot.....

How very, very true.

my thoughts, your choices

Fred W

  • Member since
    November 2002
  • From: US
  • 2,455 posts
Posted by wp8thsub on Tuesday, November 15, 2011 12:30 AM

Texas Zepher

 gandydancer19:

What makes the turnout DCC friendly is that the open point rail is the same polarity as the stock rail next to it. 

  Is that really an official definition or just an observation?

Not sure about "official," but every DCC friendly turnout I've encountered fits that description.

Rob Spangler

  • Member since
    February 2005
  • From: Southwest US
  • 12,914 posts
Posted by tomikawaTT on Tuesday, November 15, 2011 12:07 AM

I hand-lay my turnouts, use live frogs and, because of the way I install points, the open point is as (electrically) dead as Julius Caesar.

There are those who will tell you that live frogs aren't, "DCC friendly."  True, if you try a trailing point move when the points are aligned for the other route you WILL have a short.  The cure is to ALWAYS make sure the points are set for YOUR route BEFORE trying to cross the frog.

Question.  Which would you prefer?

  1. Locomotive shorts on live frog, stops the world until the breaker is reset.
  2. Locomotive rides up on closed point, derails and either stays upright or rolls over - and possibly makes an uncontrolled descent to the layout room floor.
  3. Locomotive splits the switch and goes on to a cornfield meet - aka headon collision with another train.

I know which I would rather have happen!

Chuck (Modeling Central Japan in September, 1964)

  • Member since
    October 2004
  • From: Colorful Colorado
  • 8,639 posts
Posted by Texas Zepher on Monday, November 14, 2011 8:23 PM

gandydancer19
 cacole:

DCC Friendly is basically just advertising hype to make you think one brand of turnout is better than another.

 

What makes the turnout DCC friendly is that the open point rail is the same polarity as the stock rail next to it. 

  Is that really an official definition or just an observation?

  • Member since
    January 2007
  • From: Eastern Shore Virginia
  • 3,290 posts
Posted by gandydancer19 on Monday, November 14, 2011 7:51 PM

cacole

DCC Friendly is basically just advertising hype to make you think one brand of turnout is better than another.

Sorry cacole, you are wrong on this point.  At first, I thought the same thing.

What makes the turnout DCC friendly is that the open point rail is the same polarity as the stock rail next to it.  If you look at a older Shinahara turnout, you will see that the throw bar is metal so that both point rails are the same polarity.  So that makes the open point rail one polarity and the stock rail next to it the opposite polarity.  If the opening between the point and stock rails are wide enough, AND the locomotive wheels are in gauge, you won't have a problem.  BUT, if either one of those two things are off a tiny amount, the locomotive wheels will make contact with both point and stock rail and cause a short.

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.

  • Member since
    August 2006
  • 1,519 posts
Posted by trainnut1250 on Monday, November 14, 2011 7:25 PM

You actually have several issues here:

The first is that the Shinoharas are power routing.  This means that they rely on contact between the point rail and the stock rail to power the turnout through the frog.  This set up gets sketchy over time as the turnout ages and begins to create dead zones as the points don't conduct electricity through the turnout.  I have a buddy with over 100 HOn3 Power routing shinoharas and he spends lots of time cleaning contact points to keep the turnouts conducting power correctly.  There are several fixes for this issue.

The second issue is the backs of wheels shorting against the points of the opposite polarity as they pass.  The same buddy didn't modify a single turnout when he converted to DCC and has had no problems with these types of shorts.  He runs lots of older brass as well as the latest Blackstone offerings.

Advice:  If the number of turnouts is small, I would buy Litco, Cream city or Railway Engineering turnouts that are already wired to be DCC friendly and not use the Shinoharas at all.  Absent that, I would take the time to modify the Shinoharas, not because of the shorting issue, but mainly to make your life simpler when it comes to continuity issues as the turnouts age. 

HOn3 is small enough that continuity is an issue, those points are tiny and you want the most reliable powering scheme to make operating fun.  Nothing like having to tap the loco to get it to run past a dead spot.....

Of course opinions do vary,

Guy

see stuff at: the Willoughby Line Site

  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Monday, November 14, 2011 6:38 PM

DCC Friendly is basically just advertising hype to make you think one brand of turnout is better than another.

One way to make every turnout 'DCC friendly' is to insulate both rails that diverge from the frog and add extra feeder wires beyond the frog, even if the turnout claims to already be DCC friendly.

That's what I do with every turnout, whether Peco Insulfrog, Electrofrog, Atlas, Shinohara, etc., and I have never had a problem with a loco or anything else shorting on a turnout.

 

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Monday, November 14, 2011 6:38 PM

 The curent COde 83 turnouts they build for Walthers are DCC friendly - dunno if they also modified the other codes which they sell under their own name. It's usually not a problem if all your wheels are in guage, but what works for DC doesn't always work for DCC, a momentary short when a wheel bruses the back of an adjacent opposite polarity stock rail in a  non-DCC friendly turnout when usign DC power appears and clears too fast for a DC power pack to react, so you never see anything (maybe a spark if you turn the lights off). DCC however uses electronic circuit breakers which can react instantaneously and can see a short that DC would ignore. The major thing to do with Shinohara turnouts is install an insulated throwbar and gaps so that the each point has the polarity of the adjacent stock rail. As built, the entire moving point assembly takes ont eh polarity of the closed side, this is where the momentary short can occur. If you are buying new recently manufactureed turnouts, check them with a meter and see if things are already modified. If not, it would be best to made the modifications now, before installing them. It will be a huge pain to fix it after the fact once the track is laid and REALLY hard after ballasting.

                    --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
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  • 60 posts
DCC friendly switches. Confused !!!!!
Posted by jack308gtsi on Monday, November 14, 2011 4:39 PM

I am building a version of Malcolm Furlows San Juan Central Hon3 railroad. I had this original book for years and with the new Blackstone locos  avail,  thought I would build it. I am going to use the Digitrax DCC empire builder.  I have all the benchwork done. Mirco engineering code 70 flex track down. I am using shinohara turnouts which are also installed. They are removable still.  I have not purchased the DCC system yet nor do I own any Hon3 locos.

Now my problem. In Malcolm's book he uses shinohara turnouts. He is using DCC. He cuts in gaps for the sections of tracks to isolate from shorts but does nothing to make the turnouts "friendly".  I keep reading about adding jumpers etc to prevent shorts as a loco goes thru the turnout. In the Hon3 2011 annual mag an author goes into great detail on making these turnouts "friendly" I saw the video of the San Juan Central Kalmbach made and Malcolm's  locos which are mdc models ran very well thru the turnouts.

Do I have to do this also????.  

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