Two factors determien this. The main one is, how many traisn will run at a time. This straight up determins current requirements. Small layout, larger layout, simultaneously running 20 trains will need more than a single 5 amp booster, while no more than 5 trains running has PLENTY of power with 5 amps (unless it's O scale or larger).
Second, total size, mainly length of the power bus. There are diminishing returns from using bigger and bigger wire as the length grows, but you could run a very long bus with no voltage drop using #1 wire. But good luck attaching feeders to that, or pulling it under the benchwork. So the easier thing to do is add a booster, just to keep the bus length reasonable, even if the extra power isn't really needed.
25 feet is a common rule of thumb, using #12 wire. Putting the booster int he middle results in a total bus length of 50 feet. If the total is less than 100 feet, then divide it approximately in half, and then stick a booster in the middle of each half. ie, of the whole thing is 80 feet long, then you'd have the end of the bus, 20 feet of bus, a booster, 20 more feet of the same bus, then 20 feet of the second bus, booster #2, and then the last 20 feet of the second bus.
=====B1===== =====B2=====
It doesn't have to be precise by any means.
Within those to power distrits, adding circuit breakers to further divide things is always a good idea. With HO and smaller, no one loco needs a full 5 amps, and having half the layout stop dead because one loco runs a turnout and shorts is rather annoying.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Your situation sounds similar to mine as regards number of trains and locos running at any given time during peak operations. So from that perspective, a booster might not be needed, and the single base station would be sufficient.
The reason I added a booster was because the length of the buss was getting close to or more than 40 feet from the centrally-located base station in either direction. The quarter test was failing at the extremes. By adding a booster, that issue was resolved, and as a bonus I was able to setup the booster as a reverser for the Wind River Canyon peninsula.
Robert
LINK to SNSR Blog
riogrande5761 At present I have a Digitrax Radio Chief system with a 5 amp command station/booster. Assuming I stay with that system, how many 5 amp boosters/power districts would be needed to handle the layout? I may switch to a different system but I assume whatever system it is, will need to divide the layout into power districts each with a booster. Off the top of my head, I'd guess at least a minimum of 3 power districts (main yard, mainline, staging yard) with 1 power booster each?
At present I have a Digitrax Radio Chief system with a 5 amp command station/booster. Assuming I stay with that system, how many 5 amp boosters/power districts would be needed to handle the layout? I may switch to a different system but I assume whatever system it is, will need to divide the layout into power districts each with a booster.
Off the top of my head, I'd guess at least a minimum of 3 power districts (main yard, mainline, staging yard) with 1 power booster each?
Rich
Alton Junction
I agree. You generally need boosters for more engines, not more track. If you place your command station roughly in the middle of the layout and use good bus wires and feeders, the 5 amps you already have should suffice.
I do suggest subdividing with circuit breakers. This protects the layout better and allows shorts to be localized while the rest of the layout keeps running. N addition, if you feel the need for a booster in the future, the layout will already be broken up and insulated for it.
It takes an iron man to play with a toy iron horse.
In my view,what you already have should do the job no problem. You can create power districts with circuit breakers using the one 5 amp you already have. Adding a 5 amp booster to three districts is overkill and a waste of resources.
I am finally in layout construction mode again as it gets further along, I'll need to be planning for power capacity to the rails in DCC operatoin.
The layout is planned to have:
- 1 approx 30' main yard with switching operations to local industries and engine facility.
- About 75 feet of mainline with two 20' passing sidings
- 1 staging yard with around 10 or 11 storage tracks.
Don't expect to be running more than 2 trains at a time most of the time, but occasionally up to 4 or 5. Most trains will have between 2 and 4 engines.
The layout room has two 15 amp circuits dedicated to the layout.
Rio Grande. The Action Road - Focus 1977-1983