The DCC question.

There are always questions about the control system on Trenholme Junction which is a DCC controller.

The most single important point to be made here is that DCC Control is fantastic. There has 
been nothing since the invention of model railways that has made such a dramatic difference 
as this has. 

Digital Command Control is a modern control system which is different from the system used 
in the past. The earlier system used a controller which effectively drove the track. DCC 
drives the locomotives. 

For the sake of simplicity I am only going to talk about driving the locomotives in this 
piece. There are other advantages and features which I will be dealing with later.  

There is a lot of hot air spoken about DCC, mainly from those who know (or think they know) 
how the thing works in every minute detail. They have an air of superiority about them which 
can and does intimidate a lot of people. If you are considering using DCC it is important 
that you don't let these people put you off.

This is not a definitive guide to DCC, this information is from my experiences I personally 
have endured and any specifics are of the systems I have actually used. There are a lot of 
'experts' on the internet who give advise about systems they haven't had any experience of. 
Their information must be gathered from reading other peoples experiences and therefore is 
not reliable.

Its also worth noting that some of the earlier books on the subject don't give the best 
advice, things in this world are changing, only for the better I might add.

In order to get the best out of anything the more pertinent knowledge you have the better 
the result, e.g. having the best possible trainers if you were to take up running, you 
wouldn't attempt that in a pair of flip flops would you? In the same way if you wanted to 
drive fast you wouldn't buy a moped you would buy a Ferrari. One thing you wouldn't need to 
know is how the Ferrari worked. Although I do know how DCC works because of my background, I want the thing to run my trains, I don't want to spend the time I have fiddling about with electronics.   

Some basic knowledge is required and you need to initially know the principle of how DCC 
works, without going into any technical detail, before applying it to your layout. 
There are two parts to the electricity that the locomotive picks up from the track. The 
first part is the power to make the locomotive go, the second part is the signal which 
provides the instructions to tell it what speed and direction to travel and other 
incidentals like lights and sound. The two parts are combined together and delivered to the 
track, from the controller, through two wires, one to each rail of the track. A decoder (or 
chip as its sometimes called) is placed in each locomotive and 'listens' for instructions.

I'm not going advise which is the best system to use because I can't. I haven't tested all 
of them and therefore can't give an objective view. When I bought my system, the internet 
had not quite got going and it wasn't possible to throw out a general question and get many 
replies which you can now. If you ask ten people with ten different systems which is the 
best, most will say 'mine'. Search for DCC in a search engine and you'll find all the 
manufacturers will have a website telling you how wonderful their system is. Look for the 
features YOU want and when you've made your selection, get in touch with those who actually 
have the same system, or those who have got rid of that system to ask them what they think.  

There is a section in the 'Origins' part of this blog which explains about the importance of 
good electrical connections to the track and I don't intend to go over same ground again. I 
used a different method to wire the track than was recommended by the experts and on my 
layout it works very well. There are variations to the theme but generally, they all achieve 
the same end. A rule of thumb, if you are not electrically trained, is the more copper you 
have to transmit the electricity around your layout, the better.

My first system was ZTC. The specification for this system was a main controller or a 
booster for every 50 metres of track. I originally bought the controller and 6 boosters. I 
had endless problems with the system. Trains running away, system resetting and rebooting, 
and endless resets of the locomotive decoders to the default 4 (as it was then). I spent 
more time fault finding than running trains.

I took the advise from the books around at the time and divided the layouts into 'power 
districts' each with its own booster. If you can imagine a clock face, I divided the layout 
(a big oval) into quarter hours. BIG mistake. A train travelling in the first quarter hour 
with say 12 coaches enters the second quarter hour which has cut out, stops dead and derails 
the train. It also leaves the locomotive straddling the live section and the tripped one, 
not good. If you read about this method anywhere my advise, don't use it. The only thing 
useful to come out this adventure was I took the four boosters off and connected the four 
quarter hours together, with connector blocks, to one booster. 
If a fault occurs I can disconnect the sections one at a time, at least it gives me a clue as 
to which quarter the fault is in.

All the various systems on the market, to a greater or lesser degree must work, otherwise 
they wouldn't sell. Problems can arise when connected to a layout which has some oddity 
about it or when the user has not realised a constraint on their particular system. It is 
then too easy to blame the manufacturer. In the case of the ZTC system I did blame the 
manufacturer and I was right. It didn't do me much good being right though, just cost a lot 
of money. 

This is what happened to me.

After many months of hair tearing, sending the Controllers and the Boosters back to the 
factory, I decided to run my entire layout on just one master controller. I wanted to see 
just how much it would affect control when there was over fifty metres of track connected to 
one master unit. I connected all power districts together (800 yards of track) and it 
performed near perfectly. Was I conned by slick sales talk?, yes probably, or was it that I 
took so much care to bond all the tracks so well this allowed the unit to work over such a 
large distance? I loved the cab controllers of the ZTC system. More about this system is 
documented elsewhere in the blog.

The lesson to be learned here is to build your layout, divide it into districts, join them 
all together, buy the master unit and see if it works before buying extra boosters. If you 
do need boosters you can then move power districts onto boosters one at a time.

To give an idea of the power you will need, the power consumed by my layout is about 1.1A 
when all is still and less than 3A when 8 long trains are moving together. This is with over 
80 locomotives and 10 light coaches on the layout. This is trains only, not points or 
lighting etc.

One of the reasons I bought the ZTC in the first place was the promise of a wireless 
controller, which was never forthcoming and I decided that I was so fed up waiting that I 
scrapped the ZTC and bought a Ecos ESU 20500 with a radio controller. I connected the Ecos 
to my layout (with all power districts connected together) and that worked straight away as 
well and has done to date. The wireless controller is essential to the film work I do on the 
layout, and again there are references to it elsewhere in the blog. 

A couple of other things to mention I did which you may like to know about. It was 
recommended by ZTC to put a 12 volt bulb in line with each of the districts feeds which I 
did and I failed to see any need for this and I took them out. One reason for this was to 
stop an power surge at boot up of the Master Unit. In a quest to find the many faults this 
system generated I removed them as they didn't seem to make any difference. I was also 
advised (by the manufacturer) to put a double pole switch between the track and controller 
and allow the unit to boot before switching the track on. I did do this and it did improve 
the random faults situation somewhat. Sticking plasters on what was obviously a system which 
had not been tested. I left the switches on the layout, useful for fault finding.

One disadvantage, some may say, about having all the power districts connected together is 
that if a fault occurs in one place and trips the controller, everything stops. That's OK 
with me, if there is a fault I notice if everything stops and investigate. The only time I 
could see this mattering is if you intend to exhibit your layout and don't want a fault in 
one area to affect the other districts. Most of us are operating the layout on our own and I 
don't think its a good idea to go fault finding when maybe 90% of the rest of layout is 
running. 

One very important thing I would advise is to have a separate booster to switch the points 
and use a capacitor discharge unit with it. I found that having the points switched on the 
same unit as the locomotives were running caused some erratic behaviour. Again this is my 
experience, on smaller layouts this might not affect it as much. If you are getting erratic 
behaviour its well running the layout without switching any points and observe how it 
performs.   

There is a video showing the wiring method , click the link below:
http://youtu.be/7s_mqmGcSFg

In conclusion, if you want to see the sort of control you have running DCC please have a 
look at the videos on my Channel, click the link below:

https://www.youtube.com/user/dougattrenholmebar