Some tests were done at the modular club I belong to.

I don't understand all of the electronics, and one of the guys involved is a retired electronics engineer who worked for one of the aerospace companies in the area.  There are others who understood much more than I do, but I'll try to share what I know of the results.  

The club uses the E-Z Dcc system from CVP.  I think we use 5 amp boosters, but am not sure.  With 5 amp boosters, you want frog juicers on every turnout.  If a locomotive hits a turnout that is set wrong and shuts down part of the system, lift it off, don't try to push it through.  A number of locomotives have had things fried when they caused a short!

We have found that we can run a maximum of 8 powered locomotives on any one of the boosters.  The total varies depending on a few factors.  Sound locomotives draw more power than those without sound.  If a sound locomotive is sitting on a track that is powered, it will continue to draw power as the sound will continue to operate. Even a non-sound locomotive will draw power if sitting on the track as the decoder will continue to draw a miniscule amount of power as it looks for a signal.  If you are running any older locomotives with open frame motors like Athearn blue box, or old Bowser kits, they should have their motors changed out for new can motors to reduce the power draw.  If you are planning an engine storage facility where locos will be parked when not in use, you would be wise to create blocks with shut off switches that can kill the tracks under individual locomotives to reduce power draw with extra tracks with power blocks where you can move locomotives and park them as you "dig" out the ones behind.  I think I would also set up passing sidings so that if a train goes into a passing siding to meet another train, that you can kill all power to the siding. while the other train passes.  Power routing turnouts on each end of any passing sidings may solve that problem.  Again no more than 8 powered locomotives in any booster, so the locomotives on the train that is passing on the main may need to clear the power district and move on to a different booster before the train on the siding is moved back onto the main.

You may be better off dividing the mainline into power districts and tying the staging yard & main yard into two of the mainline boosters.  Presuming that your yard will only utilize one or two switch engines during operations, and your staging yard will only have one or two trains entering or leaving at one time.

I had to take off for about 1/2 hour while writing this, so I don't know what others may have posted while I was gone.

I just checked and noticed that so far I'm the only one to

respond to your post, so I have a few more suggestions to throw out here.

To reduce power draw, dummy locomotives are your friend.  Don't use more powered units than you need to pull your ruling grade.  I'm not sure what era you are modeling.  If you are modeling Rio Grande after the S.P. takeover, but before the U.P. takeover, you might be running Ge dash 8 units with @4000 hp which would require fewer locomotives on point.  If you are modeling the mid 1960's on where big power was 3,000 hp tunnel motors, you would need more power than modern day, but less than needed in the 1950's when 2,000 hp or less was the norm.  Fortunately, model locomotives seem equally powerful whether a new super power model or a 1948 F-unit.  I have the 2020 Santa Fe Calendar which shows a train at Woodford, Ca on Tehachapi led by a Gp35 with 8 other units on point, and the caption said that there might have been 2 or 3 more helpers in mid train.  One model Gp7or 9 will probably pull as many cars as an Sd40-2 or one of the new Sd70 mac units.  So for early transition era you can fill your consist with a few dummy units to look like you have a lot of power on the point.

I have 3 boosters...

One thing I would suggest is to add toggle switches to your staging tracks. While the engines are not running, there's power going to them. On my railroad I have booster for my upper level, lower level which is staging, and my engine terminal. I would add circuit breakers , I have them as well. I keep a lot of engines on the layout. I didn't mind splurging for the boosters. Just want my layout to have the power if need be. 

Glad to see you're making progress!

Neal

Age, power variables, topology are also considerations

Are the staging yards switched, or powered all the time?  Engine tracks, van and lighted passenger car tracks, same question. There's no single answer to your question.  Are your locos older power hungry Athearn, more modern silent units (less power hungry), or sound units (very power hungry).

I would budget 1/3 ampere per modern silent unit, 1/2 A for older Athearn/P2K, and 2/3 Ampere per sound unit; these are all assuming the unit is at full throttle running upgrade, so I then dial back the total by some amount (1/3?) because they'll not all be at that performance point simultaneously.

For units idling in the yard, I tend to not do that, so I don't have much data.  I guess I'll know soon, as we'll be adding that 'feature' to our one yard shortly.

To me, it sounds like you might need one 5A booster (sounds similar to my old layout).  (is there a drawing available)?  I'd try to locate that physically as far from the command station as possible.  As far as 'districts', that's where you might want to break the layout into more sections.  Use PSX circuit breakers (I use PM42s as I have them, but if you're going to buy them use a solid state device) to feed the separate sections, and put a couple or more sections on each booster.  Down the road, if you find you need more power, you can then move one or more districts to it's own booster.

Remember, from one booster, or the command station, you can run 30' or more in each direction with a properly sized bus wire (not opening that discussion), so one power source can cover a lot of ground.  You might even try powering the whole thing from the DCS to get started, but I'd plan on one or more boosters at the far end of the layout.

Blair

Sounds like good short

Sounds like good short circuit protection is a really good idea.  It's not hard for a turnout to be set the wrong way.

The 5 amp booster with 8 engine capacity sounds about right.  If you assume 0.5 amps per engine x 8 engines, thats theoretically a max 4 amp draw - 80% of the booster capacity.  From what little I know, most modern HO engines are lower draw, on the average.

The sound vs. non-sound power comments make sense.

I do intend to create power cut-off switches to blocks in the yard and staging yard, which would probably help minimize power drain/draw and could also help with short isolation?

You're on the right track

 I think you're on the right track, Jim.  A few thoughts from my experience:

• The number of simultaneously running locomotives is the key.  From your description, I'd start with your single command station.  Then, if you find you start having problems, add another booster.  Design for the booster, but don't buy it until/unless you find you need it.
• Separate your layout into districts using PSX Circuit Breakers, not extra boosters!!  This is the single best thing you can do.  They will protect you from the inrush current of sound decoders and keep-alive capacitors.  Use one for your staging, one for your main yard, and a couple for your main line.  Power them all from your command station.  This makes it simple to add another booster.  If you find you need it, just switch power for one or more of the PSX units to a new booster.
• The cutoff switches are a good idea.  I have them on my roundhouse tracks.  Also, program your sound decoders to go quiet until they are addressed by a throttle.
• Use 14 Gauge wiring for your wiring busses to each of your PSX districts.  You could use 12 Gauge if you want, but I believe 14 Gauge will be sufficient.  It's what I use.  Place a quarter on the tracks as you lay them and make sure the PSX kicks in.  That will tell you if the wiring is heavy enough.

Happy building!!  I'm looking forward to following along.

Are the staging yards

The layout is only just going up with benchwork right now, so no track down and wired yet.  I was leaning toward adding switches to cut power to each of the staging yard tracks and possibly other blocks as well.  Sounds like it is a really good idea.

As for loco's, I have around 140 purchased over the past 25 years.  The oldest are some Life Like Proto 2000.  Most of the engines have been bought in the past 12-15  years and the older ones sold off except for a few LL P2K, No blue box Athearn.  The only possible high amp engine is a 2nd run P2K PA unit.  Most of my engines are Athearn RTR (tunnel motors/SD45's), Genesis geeps, Atlas geeps, and now 4 Scale Trains tunnel motors.

Sound, not very many but growing slowly in number.  Don't anticipate more than one sound unit in an MU lashup most of the time.

Will take onboard the need for circuit breakers for protection - seems a good insurance.

Russ: The primary focus is D&RGW 1977-1983 based loosely on Grand Junction and westward.  Rio Grande typically ran power heavy trains to avoid helpers during the "short fast frequent" train era so would plan on running 2 to 4 engines at the head end.  

Sounds like I'm in the right ball park with boosters, 2 or 3 sufficient.  Main thing is power switches on blocks and breakers.

There is a basic track plan (see below).  The staging yard runs from where the track disappears at the top right and along the left wall under the main yard to the helix.  I've drawn a early draft of the staging on a separate sheet.  I am mulling over a branchline to run from the left side of the peninsula underneath and around to the staging as well.

Thanks for the feedback Russ and Blair.

You do NOT need a booster for

You do NOT need a booster for each power district.... but you SHOULD have a power manager/breaker for each operationally intensive area...  The Digitrax PM42  splits one booster into 4 individually protected power districts. One for your main yard, one for staging, and one each for your mainline/passing siding areas.

If you're running strings of lighted passenger cars, or multi-engine MUs, you'll need to take that into consideration as well, and that might warrant the use of a booster. At an N Trak show, we had a guy once that was running 6 powered E8 units pulling a 30 car passenger train, all lit...  even in N scale, that train was drawing 4.5 amps all by itself (measured with a RRAmpMeter).

Max amps

Sometimes the FREMO layouts are a little bit larger:

But usually we prefer more boosters with less power each, usually they are configured for a maximum of 2 A or 3 A output, not more. We won't use boosters with 5 A or so. Imagine you have a short on a turnout with 4.5 A and a booster with 5 A - it will not switch off. Instead you will electro-weld your loco wheels to the switch.

Agree

I agree with Barr_ceo.  Use PSX breakers, not boosters.  

Also, I don't think you need power on/off switches in your staging yards.  I had them on an old layout, but didn't include them on my current one.  If engines aren't running, they aren't drawing power.  Unless they have sound, and the quiet setting solves that.  The on/off switches don't hurt anything, but they add to wiring and operating complexity.

I have 5 staging tracks, all with sound locomotives on them.  I have 4 or 5 sound locomotives active on the layout.  When I power up the layout, I have no issues with inrush current or power.  Most locomotives are silent until I address them (some come on because they have cheaper sound decoders without a silent setting).  I've run six sound locomotives at once with no issues, trying to trip the booster.  Oh, and my system is the same as yours, Digitrax radio chief, 5 Amp.

Use the PSX breakers.  You'll be glad you did.

Here's my wiring diagram overview.  It includes block detection for signals, so you can ignore the purple parts.  I removed the DB100a because I found it unnecessary.  I run with just the DCS100, 5 Amp.  I also replaced the PM42 with a PSX-AR auto reverser and it works much better.

Oh, and no, I don't work for DCC Specialties or get a kickback.  LOL  I just love their PSX products.  They work.

But usually we prefer more

...and that's why you set your power manager for 2.5 amps or something similar. With the PM-42, the power can be set at different (and lower) levels for each power district, which will deal with this issue without having to throw more expensive low-powered boosters at the problem. I have a 5 amp booster, but set my PM 42 districts for 2 amps. One section may trip, but the others keep going, and the booster is unfazed.... well, it's phased, but not fazed.....

I think the correct question is...

How many locomotives are you going to have on the layout at any given time, and how many of those are sound-equipped?

How many?

  Hi Jim , I based it on keeping the bus wire from any booster to it's track at 30 feet or less distance. For my layout it turned out that I could use a command station and one booster. The command station powers two power districts and the booster powers three districts. My command station and booster are each 3 amps but I don't need many engines for my layout so that's enough amps.If I had more power hungry engines I'd use 5 amps instead......DaveB

Jim....

Break your layout into as many sections as you like.  Feed all the sections with one booster and ship it through one RRAMP meter from Tony’s.  No more guesswork.  Probably save some hard earned too.  
 

Nick

Jeff, I plan on making

Jeff, I plan on making staging as high a capacity as possible. In the near term there will probably be 15 to 20 sound equipped locos. Maybe 50 engines on the rails guessing. Nick. Never heard of the RRAmp meter. How does it work and what does it do in a nut shell?

Edit: dang smart phone touch screen (why I don't want to use a smart phone as a throttle!)

Jim

A RRAmp meter measures the current being used in the circuit powering Your track.  If you have a 5 amp booster it will tell you how many amps (and less importantly volts) you are using at the moment.  Think of it as a capacity meter.

I have one and the base current used for all the tortoise switch machines and other non-locomotive amp draw is about 1 amp.  With a dozen locomotives pulling cars I’ve never seen it go over 1.5 amps on a 5 amp NCE Procab.  When the RRAMP meter goes a little above 4.5 amps regularly, I’ll buy another booster.  PSXs and PSXARs are brewers and breaker/reversers. A much better investment for the sections of your layout that need isolation and protection.

Hope this helps.

Nick

My thoughts are similar

Start with one command station-slash-booster mounted centrally to the layout and divide the layout into at least four power districts.  Put an RRAMP meter between the booster and power district unit(s). Have kill switches on each staging track; no reason to have decoders idling, sound or otherwise.  Add a booster if a) continuous power needs exceed 80% of the first booster's rated capacity, orb) the bus wire runs exceed 45 feet.  At longer than 30 feet look into using capacitors to smooth the signal's waveform.

Take the motor out of that PA1 and throw it away.  I measured the stall current on one at 6 amps, and that was on a 6 amp power supply so the true value might have been higher.  Your Proto:2000 Geeps will only draw .5 amps at stall.  I've measured plenty of those.

Likewise, cut every QSI and MRC decoder out and sell those on FleaBay.  Your wallet might not be happy but your layout and DCC system will be.

Voice of lots of experience talking.

Scott Chatfield

toggle switches on storage tracks

Do you have any lighted passenger cars? Will you ever want to park any of them in-view on the layout without the lights being on all the time? What about lighted cabooses, will you have a caboose storage track at an engine terminal?

Have a look at

these video's Jim. It might help you. 

Success.

Greetings, Filip

Excellent feedback.  Sounds

Excellent feedback.  

I could be running a  BLI California Zephyr with 12 passenger cars and an ABBA power set.

@Russ, the thing about dummies is, I have almost none and these days dummies are rare.  Companies report it isn't cost effective to make them.  Out of around 140 engines I currently have, I don't think there is a dummy among them since I sold my Stewart F9AB sets which had dummy B units.  The only way to get them would be to gut otherwise good engines.  Food for thought anyway.

@Eastwind, I have BLI CZ cars which are all lighted and a number of Genesis bay window cabooses, also lighted.  The rest of the Walthers passenger cars I have are unlighted as are the brass cabooses.  I do plan to have an engine terminal with caboose track in the main yard - I haven't fleshed out those tracks yet.

As for toggling off power on blocks, the first place I would install them would be on the staging tracks under the main yard to isolate parked trains.  The main yard, I'm open to suggestions, but I'd think any power switches installed can simply be left on if I don't want to de-power blocks in the main yard.

@Scott, sounds like a good way to methodically determine power demand rather than just spend money and guess.  I would assume the main yard, storage yard and mainline would be each a power district, beyond that ... ?

As far as decoders go, I read all the bad things about MRC decoders and avoided them completely - none.  I do have a few QSI sound decoders that came in the a Walthers F7AB set and two Atlas GP40-2's.  The rest are non MRC/QSI (a mix of silent Digitrax, NCE, TCS, Lokpilot or Soundtraxx and Loksound sound.  Oh, and whatever came in the only two BLI RSD15's - which I have read many people replace the decoders in them.  Paragon 2 I think - Utah Rwy version.

Take-away so far: it looks like rather than investing in boosters for now, I would need a PM-42, RRAmp meter and some PSX breakers first.  Then add maybe one booster if needed.

Jim

You did get great replys!

When you convert the decoders consider a Decoder Buddy.  They will make installations a lot easier and more neat!

Have a good.

Nick

Not quite, Jim.

Take-away so far: it looks like rather than investing in boosters for now, I would need a PM-42, RRAmp meter and some PSX breakers first.  Then add maybe one booster if needed.

You don't need both a PM42 and PSX breakers; generally, they perform the same functions.  The PM42 sections can be breaker or reverser, whereas the PSX products are one or the other.  The PSX and PSXAR units utilize solid state switches that are much faster than the relays of the PM42, resulting in a lot less problems with sound units.  That's why I suggested the PSX earlier.

Your DCS (presuming DCS100?) will provide up to 5 amperes of current at it's output.  You need to divide that among multiple districts; none of those districts will receive the entire 5 amperes.  So you wire the DCS output to the RRAmpmeter, and the output of that to the input of two or more PSX breakers, then wire the outputs of those breakers to one (or more) districts each.  Each PSX unit must be set to limit the current at their output to a value less than 5 amperes (else the DCS will trip first).  Set them as low as is reasonable, with an eye to the sum of loads likely to be present on the districts they feed.  

Districts can be yards, sidings, lengths of track - it's up to you.  Looking at your plan, I'd put each yard or portion thereof on it's own district, and break your mainline into several lengths as well.  Run all of the busses for those sections back to central locations.  Obviously, if you're starting with one power source, you'll likely want to bring them all back to one location; if you'll start with one DCS, one booster, then choose two locations, etc.  Wire those busses to the PSX outputs, however many you've decided on, at each location.

Blair

So PM-42 and PSX can serve the same function bar reverse loops

So you can dial back the amperage using the PSX too?  I don't have any reverse loops planned so if the PSX can limit amperage and serve as breakers, maybe I don't need the PM-42.  Thanks for the clarification.

I think the command station/booster is a DSC100 - it's whatever came with the basic Chief system back when I bought it - it's one of the first with the removable spring loaded connector terminal - prior to that they came with screw terminals IIRC.  It's only been tested once and stored since. 

That system came with the DT100 throttle.  About 5 years ago I bought a DT402D to use with a modular group and with this system eventually.  The DT100 was upgrade to a DT100R radio throttle and I have a a simplex receiver.  It would still serve as a secondary throttle.  I would still need a duplex receive for the 402D throttle.  I don't want to get too much more heavily invested in Digitrax than the D receiver as I may decide to change to a different system eventually.

But regardless of what brand of DCC system I eventually settle on, it seems the power districts and the PSX breakers can still be used right?

Thanks for the further analysis.

Great advice in this thread!

I have about 1 cent's worth to add: Try to locate your power district boundaries so that one crew causing a local short (e.g. running into a wrongly aligned switch) doesn't affect any other crews running during a session.  In the yard that might mean keeping the yard lead in the yard's power district but the main line next to it in the main line power district. 

In industrial switching areas you might want to put the rail gaps where the switcher's longest switching move typically stops when pulling the longest cut of cars onto the branch or such like.

The other $0.005 is to cut your power district rail gaps staggered about 1/8" one rather than directly opposite each other. This helps breakers such as PSX (which I find to be excellent) work accurately.