This is not really the case. I saw one example of this in a popular book on DCC, more or less stating this can be done. Yes it can be done, but when you originally wired your layout, what type of wiring did you use. Like most home layouts you probably used 20 guage wire or smaller. When I refer to smaller you should remember that the number for the gauge of the wire is inverse to the actual size of the wire. So a #12 gauge wire is larger in diameter than a 22 gauge wire. Anyway if you have runs of wire over 40 ft, you should at least go with 14 or 12 gauge wire as a bus wire. You should have one bus wire for each rail of track. Power to the track should consist of drop wires from the track itself to a bus wire. The gauge for the bus wire can be anywhere from 18 to 24 gauge, and probably shouldn't be more than 2ft in length.
Anyway, like I said above most home layouts don't have this heavy of wiring for their block control. A guide to use is:
Run of wire up to 10ft you can use #16 wire.
Run of wire from 10ft to 50ft use #14 wire.
Run of wire over 50ft use #12 wire.
If your existing layout is wired with this heavy of wire, then you may not have any problems, unless you have some reverse loops and or a turntable, then there is special consideration, which we will discuss later.
As for the GRR Model Railroad, I am fortunate enough to be starting from scratch. I am using two #12 bus wires. One wire for each side of the track. For each section of track, I am soldering a 12 inch to 16 inch long 18 guage drop wire. I am keeping my wires color coded, one bus wire is in red insulation and the other is white. For my drop wires, I am using home thermostat wire. This is two stranded wire, with each strand insulated in different colors. I found some that was red and white. This way it will be pretty simple: Red to Red, White to White.
Why am I using a drop for every piece of track. This is easy to answer. It is reliability. Yes, it can be tricky wiring such heavy wire to a piece of track and you risk melting those plastic ties. But if you do it right you shouldn't have any problems.
How do you do it right? 1.) Pre-tin both ends of the wire, after you stripped about 1/4 inch of insulation off each end. 2.) Use a clean soldering tip and a good soldering iron. I use a 45watt iron. 3.) Use thin electrical solder. 4.) Before pre-tinning use solder paste flux on the tip of the drop wire. 5.) I use liquid flux when connecting the wire to the track. 6.) Use heat sinks.
My choice for heat sinks were small copper battery clamps that you can get at most hardware stores, copper draws heat away quickly, but it also draws some solder. The reason I like the battery clamps is that they cover more space and the rubber tips on the ends make them easier to remove when done soldering. There are some small commercially available aluminum sinks out there, but they are small and the don't draw heat as well as copper. Further most of them don't have any rubber tips and you can burn your finger tips if you try to remove them to soon. The advantage to them is that they do not attract solder.
2. I have a large fleet of locomotives and it will cost me about $75 dollars to convert each one.
Well this used to be the case, but DCC has come a long way in the last couple of years. There is a larger selection of decoders and some manufacturer's are already equiping new loco's with DCC decoders. But you can have some locomotives ready run when you buy them and then slowly convert your fleet. There is plenty of information now available on installing decoders. Some locomotives you will have to hard-wire, Athearns are a good example. You will have to do away with those clips and probably change out the wheel sets. But if you can do that, you shouldn't have any problems with the decoders. Also some if not most DCC systems have instructions on installing decoders. Other locomotives are already wired for DCC, you just buy the appropriate decoder and plug it in. Also, you may have to swap out the headlight for an LED. But the LED's for locomotives are also available at your better hobby shops, and some of these shops will install these decoders, so that may be an option for some of your older steamers. Or you may want them to install one in one of your regular locomotives, and when you get it home you can see how it was done and use that for an example.
The price of decoders has come down. You can get basic ones for as low as $20 or less, or you can buy the expensive sound ones for as much as $150. After you get a couple professionally installed you can start installing them yourself.. So that big fleet will not take as long to convert. Instead of buy more freight cars, buy a decoder instead.
One caveat on decoders. The cheaper decoders may not support all you want to do. Some cheap decoders will only support two digit adressing and only give you forward and reverse. The more expensive ones may support up to four digit addresses, more light functions including bright, dim, on and off and have room for other effects such as MARS or Beacon lights, or other lights you may want to install such as ditch lights. Do as much reading as you can on your potential decoder purchase. Tony's Train Exchange, Loys Toys and other retailers on the web contain information on the decoders.
3. I don't have to worry about reverse loops or turntables.
This is a major misconception. You still have to worry about this initially. However, if you wire the reverse section correctly, you will not have to worry about having to flip the reversing switch. You will still have to isolate both rails of the reversing section. Then you can wire the reversing section to a DCC reversing module OR power booster. My recommendation is to go with the reversing module. I bought a reversing module from Tony's Train Exchange for about $40 including shipping. The module is a ciruit board and you should enclose it in a project box. Radio Shack sells project boxes, that will hold the module, for about $5. You will need a reverse module for every reverse loop, turntable or wye. I would suggest that you keep these to a minimum on your layout. On the GRR I only have one turntable.
4. I don't need blocks with DCC.
DCC does eliminate the need for a majority of blocks. However. if you have a reverse loop or turntable that section of track will need to be electically isolated from the rest of the layout. If you have a large layout, you may want to have blocks in order to isolate short circuits. This can be done by turning the blocks on and off until you find the block that is causing the short. Also if you have some locomotives you want to just park on your layout, it is better to have them sitting on a track that you can turn off the power to. There has been speculation and claims that people have damaged their locomotive or decoders by leaving a locomotive sitting on a powered section of track. It has something to do with the fact that the decoder and the engine is still receiving power and signals from the track and that the locomotive and the electronics will get hot.
What have I done on the GRR? Well I will have 4 sections of track where I can turn off the power and still maintain mainline and yard operations. This is accomplished by using DPDT switches (not turn-outs) and DPST switches. I bought the DPST switches at my local Sears Hardware Store, after not being able to find them at Radio Shack (Radio Shack was out and didn't know when the next order would come in.) I use the DPST switch as an on off switch. I connected the switch between the drop wires and the bus wire. This way I can park a the locomotive on this track and turn off the power. One such track is in my planned diesel service facility area, and the other area is on a two track siding, next to a planned industrial area. The DPDT switches are in two locations. One area is the track leading to the turntable. I know I said this will be protected by a reversing module, but if I am thinking and in the right mood I can switch the polarity or just turn off the power to this area and park some loco's as well. The other DPDT switch will be used for my programming track. This was recommended by North Coast Engineering. The programming track allows one person to program a locomotive while another person can run on the layout. After the programming is done the programing track can be turned off or turned over to track power with the DPDT switch.
I recommend that you use a small indicator lamp (12vDC at Radio Shack for about 2 for $2) and connect this up to your DPST switches to indicate track power. For the DPDT switches (especially the programing track) you may want to use two different color lamps to act as indicators of track status.
In summary, you still need blocks with DCC, but not nearly as many. Also as several adds have stated about DCC: "Run your trains not your track."
DCC WIRING DIAGRAM !
I have posted a crude wiring diagram of my DCC system under the construction photos page. Look it over and pay attention to the warning. Below I am going to write the text that should accompany the diagram. You might want to print out the diagram (using a color printer) and refer to it as you read the text. If you choose to bounce from page to text, well that is fine too. Anyway, feel free to email me if you have any questions. I am not an electronics expert or schooled in electrical theory. I am just an average model railroader, who is trying to make sense of this DCC stuff. Hopefully this information will help you out, or inspire you to look for more information. Don't rely on my information as gospel. I just try to be accurate and pass on what I have found out. It may work for you or it may not. Remember, my layout is a simple loop with a turntable. Therefore, per DCC parlance, I have two power districts, and only one power supply. A.J. (Discussion continues on page 2 of GRR DCC)
Anyway if you have futher questions, email me.
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AJ
