I just came back from Caboose Hobbies in Denver where the local "expert" on DCC and wiring suggested I wire my current DCC layout in blocks. The reason he suggested this was that once I start buying and using engines with sound, I could cause a major serge in the power source if I turned the power on and all these engines with sound were on the tracks together. Apparently sound systems really pull power.
He said having blocks and toggle switches to control the power to each block would allow me to gradually switch to these tracks where engines with sound systems sat.
Do you all agree with this? I thought once I had DCC it was not necessary to have my layout in blocks.
JRP
JRP,
I think it really depends on two three things:
I have just one big block for my 4 x 8 and I've had no problems. But, I only have two locomotives with sound. And, I usually don't just leave them idling with the sound on when they are not in use.
Also, unless the specific sound locomotive is called up with my NCE Power Cab, the sound won't come on. I don't see how I can get a surge unless I call up each sound locomotive individually - which would cease to qualify as a surge.
So...Are blocks necessary? No. Preferable? Yea. DCC power blocks are a good idea. They also come in handy for isolating shorts - if and when they happen.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
wiring blocks in DCC also lets you put in operating signals (relatively easily, as I understand it). This month's MR showed a pretty simple way to do that, though I'm not sure if the blocks were necessarily power districts, or merely for use with teh detection system involved.
As Tom pointed out, blocks will also help isolate shorts when they happen.
-Dan
Builder of Bowser steam! Railimages Site
I have the 5 amp DB 150 that comes as the base station to the Digitrax Super Empire Builder. I can power up with 11 sound locomotives at once, all idle at start-up natch, and there are no issues....ever.
I don't think his idea has merit unless you misunderstood him about using blocks, or districts, on a DCC trackplan. So, there is a lot to be said for having a track with more than 20 linear feet broken up into at least a couple of districts fed by a sub-bus into which a short management device is wired. If you break up that much track into, say, two blocks of gapped track, you can solder a tail light bulb into one feeder in series and get effective short management that way. When the short happens, the current draw will be limited by the light bulb, which will glow brightly as if you were applying the brake on your car. Locomotives in that block will stop dead, but with their decoders protected by the light bulb which is sucking up the current being wired into that block's power grid earlier than the locos themselves. In the other block, those locomotives will still work as if nothing has happened, provided the total draw of power on the layout between the light bulb and the locos that are still moving doesn't exceed the rated output max of the base station.
Simply, it is a good idea for track plans somewhat larger than what is on an HO 4X8 in many cases, but not because of current inrush...unless you are seriously underpowering your total locomotive requirements with a light power supply. If you have that limitation, then you will have to wire in toggles to keep sections of your track unpowered all the time...hardly an ideal situation.
I vote for wiring with blocks, but not because of a possible power surge that might never happen:
That said, I doubt that it's either necessary or particularly desirable to wire each block with its own on-off switch. Just wire each block to a terminal on a local terminal strip, then jumper the terminals together. Replace the jumper connections with track occupancy detectors when you get to that point of development.
Actually, a lot of this is layout dependent. The requirements for a 4X8 differ both in degree and in kind from the requirements of a basement filler with 500+ feet of track.
Chuck (modeling Central Japan in September, 1964)
If you were ever to have 10 or more sound equipt engines in the power district along with others elsewhere on the layout, the "power kill" switch would be a good idea. This is usually only needed on a very large layout where so many power hungry sound engines will need the inrush when initially turning on the layout. It is still a good idea to break up the layout into individual power districts though. Any particular spot that has a short will only affect that one district not the entire layout. Non sound engines affected by a short will only experience the power loss hesitation as the circuit breaker resets in a matter of seconds. Sound engines will stop, go silent and start up again and again until the short is cleared. Just to avoid a nusiance and make the short easier to locate it is advisable to have the use of the power districts.
On the club layout, we could very easilly have 20-30 sound engines idling or running at any time. In this case it is a good idea to do as what was explained to you.
Modeling B&O- Chessie Bob K. www.ssmrc.org
It really does depend on how large your layout is, and how many trains you intend to have running at one time. Blocks for power capacity, and to keep a short in one part of the layout from shutting down the whole thing, are usually called power districts. These can be made up of any combination of multiple boosters and/or a single booster feeding multiple sections via circuit breakers.
In addition, if you plan on adding signalling, you will want blocks for detection purposes. A typical power district will have many detection sections.If you are not installing detection right now, but plan to in the future, keep it in mind as you wire things up to allow easy retrofitting later when you do add the detection.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I don't think the "idling" thing is relevant here. It implies that if you go through the "shut-down" procedure which silences your sound engines until they are deliberately powered up, then you don't have to worry about in-rush current. I don't have circuit diagrams, but I would think that the in-rush would be independent of whether the engine is in the shutdown state or not.
Simply dividing the layout into blocks isn't going to help, unless you have individual toggles to kill power on the blocks, and you use them when you power down! Yes, they can help with short isolation, but if you power up a layout with all the blocks turned on, you'd might as well not have any blocks from an in-rush standpoint.
I put individual toggles on each of the stalls around my turntable. That's where most of the engines will live when not in service, so having them powered off is a good solution.
It takes an iron man to play with a toy iron horse.
I plan the same as Mr. B. Toggle switches on the places you store engines is VERY simple and effective. As far as trouble shooting, I have a smaller layout and have a PS-2 with 2 "sub-blocks" that are not completely isolated from the power, but you can easily troubleshoot shorts, etc.; (DON'T underestimate this strength as you are building a new layout, I presume and shorts are inevitable). Also, my 2 sub-blocks (yard and mainline, basically) allow me to keep running engines when there is a short in the other sub-block. The sub-blocks also give the flexibility for me to upgrade if needed. It only takes a few feet of extra bus wire, some gaps, a terminal strip and you easily have an upgradeable DCC system.
Brian