advanced DCC


onwards and upwards

I find that operating trains for two whole days during exhibitions, mind numbingly boring and subject to human error which quite often results in derailments and wrecks! Our little engines are very delicate and such treatment was not doing them any good. Our Desperados have been amazing doing as well as they have and have manually operated CG far better than I could in a million years but it has been very hard for them at best.

'mind numbingly boring'

Far better to be able to talk without distraction to the visitors and even have the time to visit other stands and spend time talking to old friends. I also quite liked the idea of just watching trains go by. I therefore decided that the layout would be fitted with automatic train control so only the port branch coal trains and shunting would be operated by hand.

After further discussions with Malcolm Alberry, it was decided to go the whole hog. This was a very scary decision as the equipment is not cheap and I would not have had a chance of succeeding without Malcolm's help. It must be pointed out that automatic running is useless unless you have reliable operation. This has taken a great deal of time but I can now say that we have as close to 100% train reliability as is possible.

This has been achieved by  picking up current from as many wheels as possible. Our engines are therefore plugged into 'companion cars' which also pick up current. Many modifications have also been made to the mechanisms which must travel long distances without complaint.

I still wished to retain the potential for manual operation of the layout without depending on electronics. This means that we have double control panels and it is possible to change from one system to the other by merely swapping a three plugs.

how it all works

I shall try to describe how it all works without the use of too many nerdy terms! Apologies to those who know all of this stuff!

Apart from just controlling trains, the DCC system also includes Loconet. Loconet is a system that allows all sorts of electronics to be daisy chained together with a six wire cable using phone socket / plugs. Once connected, the various electronic boards are able to 'talk' to each other. Remember, on a DCC layout, the track remains live with a special DCC voltage waveform the whole time. Digital signals are passed down the rails to the locos which control their operation after they are 'read' by the chip. This is how loco lights can be switched on and off, and speed and direction control is effected. Digital signals are also passed down through the Loconet system and provided the right bits of electronics are provided, the digital stream can control point, signal and block operations as well as provide for further train control stations.

Using such systems, the DCC control board is just fitted with push buttons. The direction of point throws and signal positions are shown by LEDs.

Sections can be cut into one rail (must be the same side throughout the layout) and the system can sense where trains are, which are also shown by LEDs. It is not that dissimilar to full scale track circuiting.  The image below shows how such units fit together on County Gate.

click on image to enlarge

Parts are Digitrax, supplied by Sunningwell Command Control and CML Electronics

circuit boards explained

This is the interface between the control panel and the railway. It is connected to the panel push buttons and the indicator LEDs. It also operates the LEDs showing train position on the layout. This decodes and controls 8 points or signals and allow. They can be adjust to operate a number of different point motors. this does the same job as the DAC 10 but only for 4 points or signals. These control the sections of the layout. These are cut into a common rail and include stop, brake and detect sections. these control the operation of the signals an interface between locnet and a laptop computer
hover over each board for explanation - do not click

All these boards are multi-functional and some require programming which is rather difficult.

This facility allows us to control the entire functions of the layout through just one cable (similar to a telephone cable). The amount of wiring is thus considerably reduced.

Once this is done, by using an interface unit, the Locobuffer, the whole network can be connected to a computer, using USB leads. Really complex sequencing of train operation can then take place. The whole concept is in effect similar to sequencing and MIDI, for those familiar with modern musical keyboard systems. The controlling software is supplied by Railroad & Co.  This is a very flexible system and has an excellent 'help' forum for the sticky questions. One also has to load a Loconet programme into the laptop.

Our first show as an automated railway was at Chatham in June 2009 and I am pleased to be able to say that the system worked perfectly throughout the weekend. Since that time, we have displayed the railway fully automated at many more shows both in the UK and the Continent and have experienced very few problems indeed.

We do have full wiring diagrams of County Gate. These are included for our own reference should problems arise. However, they may give some insight into the work that has gone into this project.

The software is well explained on this link

Below is shown a simplified animation of how the software operates. The route is previously set for Lyn and River Avon. The red dot shows point motors when activated. After the railcar and Yeo return to base, Exe and Halliday would be dispatched.

click on image to repeat

A film of the completed automatic operation can be seen here