This is probably a no-brainer for all you techies, but here goes:
Getting back into MRR after a long hiatus due to having to work for a living, so DCC is something new since I started umpteen years ago. I'm looking forward to running trains in DCC mode, but I'm wondering if I have a misconception about one of the advantages of DCC. If I'm running a train in DC and there is a slight break in the track, the train stops. Will the same thing happen if I'm running in DCC mode, or will it ignore the gap which was sufficient to stop it in DC mode, and keep going?
Thanks!
Loss of current,to the track,will stop a DCC,equipped loco also..
Cheers,
Frank
In DCC, digital commands are sent through the rails to a decoder mounted on the locomotive.
So, a gap in the rails will interrupt the signal and the locomotive will stop receiving power.
Of course, if the locomotive is traveling fast enough, it may glide unpowered through the gap and then restart.
Rich
Alton Junction
vintage modelerIf I'm running a train in DC and there is a slight break in the track, the train stops. Will the same thing happen if I'm running in DCC mode, or will it ignore the gap which was sufficient to stop it in DC mode, and keep going?
assuming that you understand that track needs to be electrically connected to bring power from one section to another, why would you think DCC doesn't need power? are you confusing the need for power with some other aspect of DCC, such as track polarity is not as important?
you may find Tony's DCC Primer helpful
greg - Philadelphia & Reading / Reading
Bear with us...we ARE trying to help, but sometimes is is a newcomer's use of terms that gets in the way. For example, what exactly do you mean when you say, "...a slight break in the track...?"
If you are running in DC and the loco runs into a dead length of track, the loco will stop. Same thing in DCC, except the decoder may have a 'keep alive' capacitor to help it to go over spotty track and it will coast another inch or three...but that's it. No matter what, there's no magic...power stops, so does the locomotive. Doesn't matter what operating system you use, and even an on-board capacitor will only last another second.
DC is not so finnicky over dirty track, and those locomotives tend to run a bit better if there is an occasional loss of electrical contact between the rails and the wheels/motor. I mean very brief ones. However, DCC needs clean track and good contact or things come to a silent halt very quickly. You have to be good at laying smooth track and at keeping it pretty clear of a lot of oxides, dried glue from the scenery adhesive, bits of ballast, bits of ground foam scenery foliage and grasses, and so on.
Second possible interpretation of your question: In DC, gaps in the rails mean a new block, and if the power isn't supplied to that block, as soon as the locomotive runs out of wipered metal tires meeting powered track under it, it stops. In DCC, we still use gaps to avoid phase conflicts, or polarity conflicts of the type you worry about with a turning wye or a reversing loop. Are you familiar with those two? However, a DCC locomotive is not sensitive to gaps and will cross over them, provided there is no conflict in phase as the metal tires pass over the gaps and momentarily make contact with the two rail ends simultaneously.
It is generally a wise practice to leave gaps here and there to allow the rails to squirm a bit for both severe temperature changes and especially due to changes in ambient humidity in the benchwork wood under them. As long as there's power in the next length of rails, and the tires and rail tops are clean so that electrical pickup is good, a small gap, even several of them in a row within inches, presents no problem to DCC. But all those tiny rail segments will need power or the loco will stop, just like in DC.
Last thing: DCC is a steady voltage to the rails. The resident decoder is what takes instructions digitally from you and portions out varied/changing voltage to the motor, but it rectifies it to a smoother DC current for the motor's use. The instructions are important. Without packets of digital info getting to the decoder, imprinted on the voltage, your locomotive's behaviour won't change appreciably. If it is stopped, it stays stopped. If you tell it to move and to accelerate, but there's poor electrical pickup under the loco where it rests, it won't do as you ask because the decoder hasn't received the information packet. Also, with poor signal packets in the rails, the DCC unit's short detection circuitry doesn't work worth beans, and that can be very expensive if a short results in a burned decoder, and maybe a ruined shell above it. You need clean track and wheels, and you want good voltage throughout the rail system so that if a short happens, the short detector quickly cuts off power to the rails and your decoder stays relatively cool.
I hope this has helped a bit.
-Crandell
Sorry, all, I guess my age is showing. I've been looking forward to DCC as a possible remedy for the age-old problem of dealing with the occasional gap in the rails, resulting in stopped trains. In my case, my layout won't have any reverse loops, wye's, or anything out of the ordinary, just a continuous loop, nothing fancy.
On balance, though, for a relatively simple setup like mine, am I wasting my money with DCC, or would it still be beneficial overall for running my train on a continuous loop setup, or should I stick to DC and keep my soldering iron hot to bridge the gaps when necessary?
Additional info: I don't know if it would make any difference in my case, but the loco I will be using is a Roco 33241 (HOe) I just ordered from Reynauld's Euro Imports, with him installing whatever decoder would be standard for this loco before he ships it to me.
Thanks to all for trying to be helpful!
If that's the only reason that you are considering DCC, stick with DC and solder all the rail joints to avoid gaps.
DCC has a lot of advantages, but on a continuous loop with a single loco, DC would be just fine.
vintage modelerOn balance, though, for a relatively simple setup like mine, am I wasting my money with DCC, or would it still be beneficial overall for running my train on a continuous loop setup, or should I stick to DC and keep my soldering iron hot to bridge the gaps when necessary?
if soldering the gaps or at least making sure the rail joiners provide reliable electrical connections, why would you think this is unnecessary with DCC? Locomotives require power.
I've wondered if DCC is worth it on my small point-to-point. And while I don't have many engines, it at least simplifies my wiring by making blocks unnecessary.
vintage modeler Additional info: I don't know if it would make any difference in my case, but the loco I will be using is a Roco 33241 (HOe) I just ordered from Reynauld's Euro Imports, with him installing whatever decoder would be standard for this loco before he ships it to me.
Are you having a sound decoder installed in the engine, or just a motor decoder?
If it is going to be a sound decoder, the engine will probably run okay on DC, assuming that the decoder is dual mode. Dual mode means that it will run on DC or DCC. However, sound decoders generally have more functionality if run with DCC.
But if you decide that you are going to run on DC, why don't you forego the decoder installation and save that additional cost?
I got back to the hobby after many years away. The sound (and momentum, etc) aspects of DCC make it really cool, and if a layout allows simultaneous operation of more than one train it's great. Ask my grandkids.
Paul
Modeling HO with a transition era UP bent
Sound and being able to run a second train on the same loop at the same time with no extra wiring are the advantages of DCC.; If neither is of interest, DCC would be a waste of money.
DCC is electricity. A gap is a gap. If the electricity doesn't flow, nothing goes. Fix the gaps mfor Dc and DCC.