Connecting up DCC to an Existing Layout and what to do with the Points.
A question commonly asked when connecting DCC to an existing layout is: What do I do with my points and should I make them, what many call “DCC Friendly”?
Why do you have to make all your points DCC Friendly – you Don’t !!!!!!
I deliberately don’t mention this subject when discussing DCC to a “newbie” or ones thinking about going DCC. I find that many already have heard about this and it turns them off wanting to go DCC. My ultimate aim is to get modellers to use DCC and then have a layout that can be operated without all the block control limitations that DC has and to also unitize all the special effects that DCC brings, eg. lights, sound etc. I connected DCC to my existing layout with out doing a thing, and others have also. All I did is “chip” a loco and I was running.
My attitude about points and DCC is that if your layout worked with DC, then it will work with DCC. This also includes using the existing wiring. Stating this, I understand there are conditions. I therefore suggest using a 12 volt 21 – 27 watt automotive lamp in series with one of the track feeders. This will look after any inadequate wiring that the layout might have. It also de-sensitises the DCC system. If there were any “shorts” at the points that went unnoticed in DC, they will go unnoticed in DCC, using the light globe. The DCC booster internal circuit breaker will not trip.
Making points DCC Friendly is just an extra chore, and I want to play trains and enjoy the features that DCC brings. For a more detailed explanation of what is happening on your DCC layout and what happen with the same layout in DC, see the section below.
This is the same, when there is a short for some reason on the layout and the inadequate (small gauge) wiring did not allow the full amount of current of the DCC system to flow and then tripping the circuit breaker. This and any type of short, whether it is a momentary or continual short, will result with the 12 volt lamp illuminating brightly with a flash (momentary short at the point) or on continuous (running against an incorrectly set of point etc).
If you a confident that your layout wiring is adequate and the maximum current of the DCC system can flow (to sense a short), then using the 12 volt lamp is not necessary. In this case, the booster’s circuit breaker will trip, when it senses a short. Many layouts that I operate on, work like this. BUT whenever someone runs against an incorrectly set point, that will inevitably happen many times during an operating session, or the wheel flanges of some locos are on the slightly larger size or other tings that may create a short at the points, the whole layout shuts down. This can be very annoying, depending on what you are used to and your tolerance level.
I use Peco code 100 at the moment but I may change to code 75 on my new layout (still to decide) and I only have a few, if any shorts, but I operate with 12 volt lamps.
Others that use code 100 without the 12 volt lamp and layout tat use code 75 (or 83 etc) don’t have that many shorts. These owners just persevere with these shorts. I operate on a few layouts, and shorts are part and parcel of operating. The effort to reduce these (modifying points, rectifying rolling stock, relaying a badly aligned point etc is TOO much trouble and requires effort and time. This time and effort for them is better spent on something that they prefer to do, like scenery, building locos and structures etc. The point here is there is only 24 hours in a day, and different people have different priorities. Some can tolerate a short or two but others, hate them. The owner has the final say as it will be his time and money that will be required to reduce the shorts and layout interruptions.
Layouts that use Peco code 75, I have found, have many more shorts due to the finer clearances. This makes the track less tolerate to shorts that are mainly due to loco drivers with a little more side play, poorer track alignment and wheel sets that are slightly out of gauge. Better track laying with particular emphasis of the way point are “laid” and some maintenance on rolling stock will fix this. Loco drivers are another thing and of course the pony truck that invariable does not traverse points 100% of the time, are a little harder to rectify. Rectifying some of these problems, will reduce the occurrences of a short whether it be a momentary or a hard short.
Therefore my recommendation for an existing layout is to see what happens and be guided by what results you get with your individual layouts. You never know, your layout may be trouble free or only the occasional shutdown. For single operator layouts, shorts and shutdowns are tolerable due the operator will have to “fix” what caused the short (select the right route etc), so no advantage here. But multi operator layouts, this is another story. There are tradeoffs with everything in life.
Peco Electrofrogs and Insulfrogs.
Both types of points rely on the contact between the point rail and stock rail for power to the point rail and the frog (and further for the Insulfrogs). This “contact”, whether is just is the actual physical contact of the two rails or the physical contact and a small “wiper” contact under the point rail, deteriorates over time due to tarnishing, ballast etc and become unreliable. Also, the open set of point/stock rail are at opposite polarities. This is what causes the shorts. These shorts happened in DC but went unnoticed, but in DCC they cause the booster’s internal circuit breaker to trip. This removes the power to the whole layout. In DC this was not a problem, but in DCC is is a very noticeable problem – total layout shutdown.
Along with the possibility of the “contact” (discussed above) breaking down, and these shorts at the “opposite polarity” gap between the stock/point rails, this is why modellers modify their Peco Electrofrog and Insulfrog points. This modification will lead to more reliable operation but does come at a cost. If it is an existing layout, this could be nearly impossible to contemplate making all your points DCC friendly. So this is why I recommend to modify the problem points when a problem happens.
For new layouts, certainly “best practice” would be to make all your points DCC friendly, prior to laying them down. BUT both types wil require a Accessory Switch of some form to power the frog.
See Allan Gartner’s site “Wiring for DCC” for a additional explanation about Pecos and others at:
http://www.wiringfordcc.com/switches.htm
In endeavouring to get the most reliable running layout in DCC, will require extra effort and expense. Each individual will have to decide what he or she is going to do. Thus decision can be quite a difficult one, and may require much more investigation. I thoroughly recommend for existing layout to just go with what you have got, and attend to problems, if and when they happen. There are only 24 hours in a day and we do want to play trains.
Just to confuse the issue a little more, my present thinking for my own layout is to have “Dead Frogs” This eliminate the accessory switch and wiring, but can cause locos to stall on points as the un-powered section of rail is much longer than in a Peco Insulfrog point. Increasing the amount of pickups and operating long wheel based locos will reduce these stalls. But a 0-6-0 will always stall on the points. Maybe live with this (use a 5 finger shunt) but wiring is much easier and no switch.
See Gerry Hopkins’s “dead frogs” method at:
http://www.nmra.org.au/Hints/Turnout_Tips/Turnout_Tips.html
Why do you have to make all your points DCC Friendly – you Don’t !!!!!!
History: We operated our layouts on DC without any problems except for a loco stalling over the points. This could have been reduced by installing, if using Peco, Electrofrogs instead of the Insulfrogs.
There did not seem to be any shorts, anyway we didn’t think there was. There really was, but we did not see them. The layout dead not go dead, the operating loco just slowed and picked up power again when the short “disappeared” due to the momentum of the loco and the train. Anyway, there was no problems with our points. They were very DC friendly. The shorts I am talking of a re the ones caused by the back of the wheel coming into contact the opposite polarity “point rail” – a momentary short.
The layout worked great.
Connect up DCC and there are layout shut downs GALORE. This becomes very annoying, especially if there are a few operators, but for a single operator, it is tolerable. All I did was connect the DCC system to the layout that others said would gives me a better operating layout. Now I have shorts that remove power to the whole layout.
The reason: When operating DC, each train was controlled by a separate “cab”. If the train was operated over a few “blocks”, control would have to be “switched” but still only one loco could be controlled. If any locos were in the same block, then that loco would have to “isolated”.
When there was a short, and there were just the same amount of shorts because we are still operating the same locos with the same wheels and operating on the same layout with the same track and the same points, BUT the DC controller just had a current limit that was exceeded for a fraction of a second, but the loco would continue on, most of the time and we did not even know we had a short.
Other operators would not have known, because each DC cab had it’s own “current limit” and possibly its own power transformer.
In DCC because the WHOLE layout is powered by one DCC booster (mostly on small to medium layouts), there has to be some form of short protection (the DC cab had this with the current limit), because DCC shorts can have much more current flowing to them, depending upon the type of short, you could cause some serious damage. A 5 amp system at 14 volts equals 60 watts, which is the same heat as a large soldering iron. This 5 amps has to be “disconnected” and it is, by the booster’s internal circuit breaker. The booster circuit breaker will reset in about 2 to 3 seconds, apply power to the layout. If the system still senses a short, it trips the breaker again. This process continues as long as the short is still present. Once the short is removed, the system provides power to the layout, again.
Now for the “little” short that happens at the points from the back of the wheel contacting the “point rail” that goes un-noticed on the old DC layout is a major problem on a DCC layout. The system trips and removes all power. The un-noticed momentary short in DC is now a 2 – 3 second complete layout shutdown. The system is acting as it should. DCC is extremely sensitive to shorts because of the 5 amp capacity of the short.
There are many other reasons for these shorts, like the scale we model, the code of the track, the accuracy of our models, operating with very small tolerances like fine scale, baseboard construction, vertical displacement of the track, even the actual point design etc. These will all vary and will depend on the layout.
What to do:
Items 1 and 2 will reduce the shorts.
What one modeller does will depend on the amount of shorts he has and how much it irritates him, This will determine how much time and money he throws at the problem, some will live with. I have over 100 Peco points on my layout but I have not made any of my points DCC friendly. I use the 12 volt automotive lamps for power division and this also doubles up as a form of short management. I love these lamps. See my 1156 notes
I personally feel that to make a layout 100% trouble free can cost a lot of money and consume a lot of time. I can live with a less than perfect layout. All of us have different levels of the many disciplines that are required to build and operate a great layout. I need to spend some of my time on the disciplines that I am below par on, like scratch building structures, painting and weathering my locos and rolling stock, making scenery etc, so that time money and effort that can be saved by using lamps to de-sensitise the DCC booster instead of making these points DCC friendly, can be dedicated to those many areas in my layout that are deficient. You too can put up with a few shorts, it’s not the end of the world, that many will tell you, by the emphasis that is placed on making your points – DCC Friendly.
Making your points DCC friendly is not the only way to manage shorts. Whether you go down this avenue will depend on you. You have some options.
So as I said in my opening, Do you have to make all your points DCC Friendly? – you Don’t !!!!!!
Remember there is no best way of doing things, just what is best for you. You can only decide this.
Another saying is “ If it ain’t broke it don’t need fixin’”