Been making alot of progress on the layout and think in about week I will be wiring it for DCC… my question is, the mainline is just about laid. How do I break into blocks without using plastic rail joiners Since like I said the maine line is just about done…
thanks
Mike
One option is to leave the mainline as its own block and have other areas be their own blocks. As long as the mainline itself will have no more locomotives on it at one time than your booster can supply, you should be fine. The downside is that of the mainline is really big, it could make troubleshooting more difficult and it makes the wire runs longer.
Typically, you don’t want to “block” DCC. Instead, a large layout would be divided into “power districts” with separate boosters. For a smaller layout with a single booster, you might want to isolate some sections, as Jeff suggested, for the convenience of troubleshooting. Separate circuit breakers for these sections make will make the overall layout more reliable.
You do need to isolate reversing loops, just like in DC. You can do it manually with a toggle switch, just like DC, but I’d highly recommed using an automatic reverse loop sensing circuit. I’ve got a couple of these from Tony’s, and they work great.
Mike, if you do need to break the layout into blocks…
(side note…There are really good reasons to want to do this in DCC, as MisterBeasley indicates power management for larger layouts, but even on a smaller layout, blocks from the same booster can be protected against shorts, to help the layout run better. Also there is the issue of blocks for detection and signaling.)
…and the track is already laid, then the best method is to cut thru the rails with a rotary tool. You can then fill the cut with styrene sheet and trim and sand it to shape. Once painted and weathered you won’t know the gap is there.
I will be blocking mine for signaling which will occur sometime down the line and power management . I think that it is easier to do it at the start.
My two cents…Ken
Use a thin blade track cutting saw (such as an Atlas) or a thin cut off disk (such as Dremmel) to cut the rails where the block is to be broken. Fill the cut by gluing a shim of plastic into it, and triming it to match the rail profile. Filling the gap prevents it from closing at a later time due to rail expansion.
just so I don’t get confused, if I use power districts with boosters and circuit breakers, I won’t have to cut small gaps in the tracks?
thanks again
Mike
No. Districts are the DCC term for blocks in DC. It is no different than DC as far as gapping rails and such. That is one reason why the move from DC to DCC isn’t so difficult. You just map the booster to which blocks (districts) you want a particular booster to power. A purist might say a power district could be made up of a couple of blocks. What they mean is that a particular booster may supply power to multiple blocks (though their own breakers) to form a district. This would be no different than a throttle pack providing power a set of blocks in DC. The only difference are that DCC requires DCC compatible breakers whereas DC can use normal breakers.
Mike, you may be well beyond this, but I’m going to throw this out there for others who may be looking to latch on to some information.
In DCC, power districts gap both rails. The distinct districts (blocks) are either attached to different boosters or through some sort of power management devices on the same booster. The method will depend on things like current draw requirements, autoreversing needs, etc.
Detection sections gap only one rail. Depending on the detector (I use Digitrax), the gapped rails get their power from a lead to the block occupancy detector, which gets its power from the bus. There will likely be several (or a ton of) detection sections in each power district.
Power districts should be planned for conservatively (worst-case). As some have stated here and in other threads, they make troubleshooting easier and keep the entire layout from shutting down over a single short somewhere, like on a siding.
If you think you will want signals down the road, or think you will have a desire for occupancy detection (computer control or monitoring, or just a hidden section of track somewhere), installing detection sections up front can save you some headaches later on. Until you actually install the block occupancy detectors, just wire the gapped rails to the DCC bus. For the cost of a gap or insulated joiner, doing this during the track laying will give you some flexibility down the road.
If you were going to have a signaling system, using current sensing block detectors, wouldn’t you need to insulate both rails in sections to create blocks?
I think some of the posts answering your question here haven’t been perfectly clear on this point.
You have to cut gaps in both rails between power districts to completely isolate the district. Each power district needs to have its own booster.
You do mutiple power districts in DCC for two main reasons:
To increase the ability of your system to run more trains at the same time. The assumption is if you split the layout up, some trains will be in one power district, while other trains will be in another power district, thus increasing the number of trains you can run before you max out the amp capacity of your booster.
To allow trains to keep running even if you get a short. DCC boosters have short protection built in, and temporarily shut down if you get a short as a protective measure. This is both good and bad – let’s discuss this last point more.
SHORT MANAGEMENT AND DCC
If you use amp capacity only as the driving factor for where to block your layout and put power districts, you can end up with large segments of your layout going down anytime someone has a serious derailment or runs a live frog turnout when its thrown against them.
It’s legendary for DCC layouts to have this issue and to routinely hear cried of “ALRIGHT! Who shorted the layout?” at op sessions.
You can aleviate this problem somewhat if you plan power districts based on where shorts are likely to occur FIRST, and then add in booster capacity considerations SECOND.
Shorts occur most frequently on a layout at complex trackwork like turnouts. This means any location on your layout with a lot of turnouts close to each other (like yards) should be the
No, signaling sensors only need to be on one rail.
This is a different thing from blocks created for power districts. One can have (and probably want to have) many signalling blocks within each power district.
Great lesson Joe. I also seen the light bulb short protection explained in Allen Gartner’s web site, but your video really sheds light on the subject (pun intended) and makes it very easy to understand. I noticed it also prevents damage to the rails when you shorted out the rails with the coin. Without the bulb, a short like that, as much as five amps, could pit the rail from electrical arcing if the circuit breaker is a little slow in tripping.