I have a double track mainline and other tracks approx 400’ long. It has worked fine for me. I have added approx a 125’ branchline and it seems a little slower and when I do the “quarter” test it still shuts down but I don’t get the same cutting in and out and noise showing where the short is that I used to. I have not divided the system into sections or added any power boosters. the track has 16v at every place I checked. I have a MRC Prodigy Advance DCC 3.5 amps. Have I got too much track and if so how do you add power? Thanks for any help.
Just so you know, forum experts say not to mash on the quarter, just put it on the track.
Power needs are dependant on the number of locos and sound you are running, not distance. If you have an inadequate number of feeders, it may fail the quarter test. Are you running switch motors or accessory lighting off your bus?
Someone is going to ask, so it might as well be me, what gauge is your bus wires and at what interval are your feeders? Is your Prodigy plugged into the middle of the bus so there is 200’ left and 200’ right or is at the end? Is the branchline in the middle of things or is it tacked on the end?
You may have 16 volts of power, but you really need to measure under load. How many pairs of feeders power the branchline? How far apart is each pair of feeders along the branchline? How far from the booster is the closest and farthest part of the branchline.
As far as power districts and circuit breakers are concerned, they are useful to segment the layout into sections, but that alone will not add power to the layout or to the branchline. My guess is that you are experiencing voltage drop.
Rich
What scale, how many locos, sound or no sound? Depends on how much current the locos require. Any other devices using the DCC power?
Any issues at our club, we would clip a AC voltmeter to the booster output and see what voltage we had and the probe the area with a slow running loco load to find a defective feeder with a lower voltage.
Sometimes we would just do the quarter test. Depends who was at the club.
Rich
what voltage do you measure with a loco running on that track?
Thanks for the replies. The bus is 14 gauge with feeders to the track every 7 or 8’ Track is code 100 flex track, all joints are soldered except at turnouts. I have the base unit and 2 handheld throttles. There are 3 extension plates (no boosters) going from the base unit to one extension plate, then the 2nd, then the 3rd. I have 18 locos on the layout, only 3 have sound and only 3 0r 4 engines running at a time, the most I have had running at one time is 10 engines, the grandkids like to see more than one train running at a time! My track only reads in AC and hasn’t read below 15v. I do the quarter test by placing a quarter on the track.
Did you continue the power bus under the new section? What size wire is it? What’s the actual distnace the wire runs from the main system? If it runs more than 50 feet or so, you may need a booster located closer to the far end not because you need more power, but because the long wire run causes too much voltage drop. If yoou have the system unit in one corner, you might be able to solve any issues by locating it closer to the center of all the wire runs to minimize the distance any of them goes.
–Randy
Sorry, read some more points. Lights and switch machines are separate. The base unit is pretty well centered as the mainline is basically a large oval and the branch is a reverse loop.
The power flows through the Bus and the rails. If it is interrupted at one of your turnouts where you have not soldered the joiners this would increase the resistance. Yes/no just asking.
With a 400’ double mainline and a 250’ branchline, that is a lot of track to be powered. Test various points on the branchline, where you notice the slowdowns, under load and measure the voltage that way. It sounds like you have enough feeders, so a second booster may be needed to avoid excessive voltage drops.
Rich
How do I add power to the layout other than just the base unit?
I am kind of surprised that you have all that track and have not divided the layout into power districts. I will defer to others more knowledgeable, but if your 3.5A system is working, then if it aint broke, don’t fix it. If you add an MRC booster, I am sure there will be a really neat diagram which will show you how to add the booster.
And sure enough, there is a diagram on the MRC website that shows how to connect a booster. And, I am also sure that if you called MRC they would be happy to help you out.
Thank you, I will do that.
I am nothing if not cynical…If you are going to spend 200$ or so on a booster, plus the cost of a cable, I am sure MRC will be happy to talk to you on the phone.
It may be premature to decide to add more power to the layout. Yes, a second booster would do it, but if you have a 3.5 amp system and 16 volts of power across the layout without load, then you need to find out where the voltage drops are occurring. Voltage drops can often be remedied with additional feeders, reconfiguration of bus wires, or relocation of the primary booster. If it were me, I would be doing some testing under load on that branchline.
Rich
Based on the OP’s original post, it sounds like if there is any voltage drop it is in that branchline. If the feeders are at 7 - 8 ft, maybe adding feeders on that branchline will solve any problem.
I would really like to see a track diagram to see where that 125’ branchline is situated relative to the 400’ mainline and the location of the booster.
Rich
Makes sense to me, Rich. And, I wonder if there is a sub bus feeding the branchline.
Hi,
A 3.5 amp system is obviously way too small for 400, much less 525 feet of track. While having feeders every 3-5 feet will help keep “the same” power to all portions of the layout, it just won’t be enough to successfully run trainS (PLURAL).
What would help is at least one booster - and I would guess that a minimum of 8 amps (total layout power) would do the trick.
To clarify above…a 3.5 amp system would - if sufficiently wired with a plethora of proper feeders - run A train all over the largest of layouts. BUT, if one wants to run trainS (Plural), then more amperage would be needed to run them all.
This raises an interesting question about which matters more when determining the amount of power required to run an HO scale layout - - - the length of the track or the number of moving locomotives, sound and non-sound. Voltage versus amps. I would argue that it is the number of locomotives, sound and non-sound, rather than the length of the track.
When do you notice the drop in speed on the branchline? A non-sound loco will typically draw 0.25 amps, whereas a sound loco can draw as much as 0.50 amps. Four locomotives running at the same time probably draw between 1 and 2 amps. Ten locomotives running at the same time would probably draw between 2.5 amps and 5 amps. A 3.5 amp booster would shut down if the current draw exceeds 3.5 amps.
Rich