The Adirondack Line
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Digital Command Control (DCC) Why DCC? Why would I use DCC with N scale - things are small enough already, let alone the need to install DCC decoders in locos. For those timid folks, take heart. Installing DCC in N scale locos is not that hard, one has to find room to put them in the loco and it is all just a bit smaller. Well, I have been sold on DCC since the early days of the NMRA standard being developed. My thanks to all those on the DCC Committee of the DCC Sig and the manufacturers who took their personal time and had the persistence to see it through. I was one of the early purchasers of the first DCC systems in 1994 to this standard and frankly I would not change back to DC control. So why am I sold on this capability. I think the main reasons are the simplicity of wiring (no more blocks and switches going back to control panels) especially with a new layout, and also the ability to control locos independently and hence manoeuvre trains in prototypical movements. Recent developments of radio and infrared throttles, releases the road engineers from being tethered to the benchwork and enables true 'follow that train' movement. In addition, the ability to install stationary decoders, which are connected only to the track and located where you need them, to control switches (points for the Brits) and others that detect the presence of a train through detection circuits is a huge wiring advantage - no more bundles of wires snaking from central panels. Mobile decoders are now coming available which can be easily inserted into DC locos, through co-operation between decoder and loco manufacturers, even in N scale!!!. Another advantage of DCC, is the ability to interface a computer to the layout. I plan to use one for automatic serial and parallel staging yards and also to run the 4 track Water Level Route to simulate heavy traffic. I do not have enough room for all the operators that would be required!!. The significance of the NMRA standard is now reaching its original objective to protect the user and enable us to purchase systems or components from different manufacturers, with more and more manufacturers coming on line. The most significant entry into DCC was MRC (one of the big USA DC throttle manufacturers), who recognising the potential of DCC, developed and released their own simple DCC unit together with DCC installed locos. In addition, one has only to compare the hobby magazines over the last 5 years to realise that this is a technology here to stay. Also, with improved technology, volume production and competition, the prices are now considered acceptable. As you may have guessed by now I am great supporter of DCC and have delivered clinics at our annual NMRA British Region Convention and attended train shows with colleagues to promote this technology within the UK. I am fortunate to have Digitrax, System 1 and North Coast Engineering systems, so have been able to demonstrate the DCC compatibility between these units, enabled by the standard. What is DCC? I am not going to expand on this subject as there are many good sites to help you. Have a browse around if you are interested - but please remember to come back again!!!
How will I install it on the layout? First, let me point you to some great sources of information available on the Net, which DCC enthusiasts have taken the time to share their knowledge with us all. Take the time to browse these sites, it will save you a whole host of time and frustration. They also have many more links for your enjoyment. Allen Gartner A great site for ' how to wire' your layout - many tips and suggestions Model Railroading & DCC John Tompsons DCC pages John Kabat Great DCC software Don Crano A lot of good stuff Jean-Louis Simonet A great way to start in DCC, plus more (Bug flag and follow pointers to DCC) In addition to the information on the web pages and in books, here are some other considerations that I have learnt and feel are important for wiring DCC layouts. Please note that a DC block controlled layout can be simply converted to DCC by setting all the blocks to the same DC throttle, and connecting a DCC system in place of that DC throttle. When one is considering installing DCC, one has to think a little differently to gain the maximum benefits. DCC is designed so that any number of boosters can be controlled by one DCC command unit. For a start, we are all use to DC wiring which usually only has one loco (or maybe two locos, if being run as a pair) to worry about in any given block. Now with DCC, we can have a DCC command station and a booster (power dependent upon scale used) within one booster district (complete areas of track all connected to one booster). That booster district (sometimes the complete layout) will support many locos being controlled independently by different throttles. Many layouts, including mine, will have multiple boosters due to the fact that over the whole layout, as many as eight to ten trains may be running at any one time and hence exceed that capability of one booster - N scale one uses traditionally a 5 amp booster. So we have to think ahead as to how many trains are expected to run within a given booster district and plan the appropriate number of boosters to be used, feeding selected districts. In addition, the boosters have short circuit protection. Here the booster will shut down and automatically come on line again once the short has been cleared. This is a benefit and a disadvantage. Imagine a layout with only one booster, with trains running happily on the main line. Someone is switching in the yard and accidentally derails a car whilst uncoupling. Now the whole layout will shut down, all trains will stop, until the short is cleared. So in this case, it is sensible to think ahead again and plan for a separate booster feeding the yard. A short can also be created if one runs into a incorrectly set switch. There is a simple circuit that can be installed in each frog feed that will over come this problem. Insert a car taillight (rearlight!) bulb, in series with the frog feed. Here the short circuit is sensed by the bulb and dissipated across the bulb. The loco will halt, the bulb will light, but not trip the auto short circuit of the booster. The US bulb is #1156. It is also a good idea to be able to switch off sections of track within a booster district to enable isolation of short circuits, permanent and temporary to assist in identification. In this case, the switch is usually hidden adjacent to the section of track, and is usually never touched. But it this there if you need it. So with these facts in mind, how do I plan to install DCC booster districts on my layout. I plan to use 5 boosters Boosters 1 and 2 will serve the Level 1 & 2 main lines including the hidden serial staging on level 1. This will include the 4 main lines through Utica passenger terminal and yard, but not the yard, engine terminal or industry spurs. Booster 3 will serve Utica yard, engine terminal and industry spurs. The areas where shorts may occur during switching operations, etc. Booster 4 will serve the whole of the Adirondack Line from Utica to Big Moose / Raquette Lake. I may add another one from Thendara up to Big Moose, and leave the original serving Utica to Remsen. I will plan the bus wiring to allow this to be easily accomplished. Booster 5 is a special use of a booster providing auto reversing within the upper and lower staging area, turntables and 'Y's. DCC wiring. It is normal practice to run twin wires from each booster under the tracks that are going to be served by that booster. For very large layouts like mine, the recommendation for main 2 wire booster district bus is to use a heavy gauge wire to minimise voltage drop. For example, 12 AWG, which is equivalent to house wiring, either single or multiple core can be used. From this bus, smaller cabling 18 - 24 AWG is can be used and it is recommended that these are installed every 3 - 10 ft on all tracks within the district. OK, this seems like a lot of wiring, but remember that the feeders are only going to the bus under the track and not to some central control panel. These feeders can be mass produced on a bench and then installed. I do not like soldering under benchwork - solder always goes where it is not intended. Fortunately, 3M has produced an Insulation Displacement Connector (IDC) that can connect 12AWG wire to 20-24AWG, crimping the connector with just with a pair of pliers. These can be purchased from Mouser in the USA, under part number 517 - 567. DCC Throttles I plan to use either radio or infrared throttles on the layout to give the operating crew freedom of movement. I may use a tethered throttle for the Uitca engine terminal, just because I have one available. DCC with a computer I plan to use Winlok, which is a software package specifically design to control and operate model railroads. It provides the capability to build a visual track plan (including a CTC board) through which one can control switches, signals and other DCC friendly devices from a single location. I plan to use this as a CTC dispatchers board. In addition, computer throttles can be created and locos run directly from the computer, with predefine routes. I will use this feature in the staging areas and on the 4 track Water Level Route This package has friendly screen layouts and a programming language. |