Perspective Railpro user has some questions... Signal Range?

[KB02]

Hello All!
   This is my first post (aside from the Introduce yourself post). I have been considering making the switch from my DCC system and converting everything to Railpro. My biggest hang up (aside from the cost), is understanding the technology. I have been trying to read up as much as I can about it - including the entire FAQ section of Railpro's website - but I have found a few questions still needing to be answered and was hoping the group knowledge here could help me out.
   My layout started as a simple DC layout on a 4x8 sheet of plywood. Soon the curves left the boundaries of the 4x8 and, as I wanted to run more than one loco at a time, I added in Block wiring. As the railroad expended even further and took over the adjacent room, I came to realize the limitations of my simple DC set up and converted everything to DCC (while still keeping a small section switchable to DC for unconverted locos and new engines that didn't have a DCC Decoder in it yet, etc.). The vast majority of the locos in my fleet are old DC locos that have been converted to DCC with only a couple that were built in recent years with DCC specifically in mind (they run great compared to the others, too). SO, I am no novice at wiring and have obtained a pretty good working knowledge on the DC-DCC differences. But with Railpro, I'm a little confused...
- Railpro runs on DC, correct? Not AC like a DCC system?
- If this is true, can a Railpro loco run on any DC layout as long as the power is set to a certain level?
- At what voltage does it run?
- If I wanted to spend the minimum for a "Test Set-up" on a simple oval, could I just get the basic LM3 module and the computer interface and use an existing DC power pack to power the track? Or is there something special about the Railpro power supply?

Next: Right now, my layout is powered by a 5 amp DCC booster. This has been working well, but with the next expansion that I am planning I will be breaking it up into two power districts as the sheer size of the layout extends a good distance away from the current power supply.
- Would this be the same case for a Railpro layout? I've seen the repeaters, but those are for radio control signal, not power, right?

My layout mostly just goes around the walls in a 13'x32' room, plus a 4'x8'(ish) section on the other side of a wall.
- Would one power supply suffice, or would I need two?

Okay, that's enough questions for now. I'm sure I'll come up with more, but I'll let the group digest those to start with.
Thanks for your insight and assistance.

-Bob
KB02

[William Brillinger]

- Railpro runs on DC, correct? Not AC like a DCC system?

No, RailPro will run on DC Power or DCC power. You can place a RailPro equipped locomotive on any DCC layout and run it with your RailPro HC or CI-1 without worry. RailPro only draws power from the rails, it does not care if it's DC or DCC power.

- If this is true, can a Railpro loco run on any DC layout as long as the power is set to a certain level?- At what voltage does it run?

The sweet spot is between 13 and 15V on the rails. Max and Min are 12 & 18V
More info on the LM's:
https://www.ringengineering.com/LM-3S.htm
https://www.ringengineering.com/RailPro/Documents/LM-3Instructions.pdf

- If I wanted to spend the minimum for a "Test Set-up" on a simple oval, could I just get the basic LM3 module and the computer interface and use an existing DC power pack to power the track? Or is there something special about the Railpro power supply?

All you need is the CI-1, a windows PC, and an LM-3 or LM-3S and you're ready to test on your existing DCC layout.

Next: Right now, my layout is powered by a 5 amp DCC booster. This has been working well, but with the next expansion that I am planning I will be breaking it up into two power districts as the sheer size of the layout extends a good distance away from the current power supply.
- Would this be the same case for a Railpro layout? I've seen the repeaters, but those are for radio control signal, not power, right?

The repeater is for radio signal and it built into the PWR-56. It is best not to run from a basic DC powerpack as a proper filtered DC output is better for the equipment. The PWR-56 provides smooth filtered power with short protection, and some advanced feedback to the controller performance metrics.

My layout mostly just goes around the walls in a 13'x32' room, plus a 4'x8'(ish) section on the other side of a wall.
- Would one power supply suffice, or would I need two?

This is a link to my track plan. I only run 2 or 3 trains at a time, but it runs perfectly well with only 1 RailPro PWR-56 power supply. I have approximately 180ft of mainline. https://www.pdc.ca/personal/Blog%20Images/2013-11-20%20BNML%20Trackplan%204000px.jpg

I hope this answers most of your current questions.

[KB02]

Wow! An 82” lift out? Eat your Wheaties, Bill! 

Seriously, nice layout. I would say that if you run well off of one power supply, then mine would, too. I will only be around 110 feet of double main line when I am done. And like you, would only be running two or three trains at a time.

Thanks for your answers, they really do help.

-Bob
KB02

[Alan]

Layout size is not (directly) the determining factor when considering power supply. Electrical resistance between the power supply and the locomotive(s) is the important criteria. Steel rails have relatively high resistance compared to copper wire so a separate wire pair (power buss) with feeders to the rails is commonly used. You can have a wiring run as long as you wish providing you use a sufficiently heavy wire size for your power bus. Bigger wire = less resistance. You can do the math to determine wire size or simply use 12 gauge wire and not worry about length.

As you know DCC uses an AC square wave on the rails. Wire resistance is effectively much less with AC current than with DC current. Therefore, DCC is less sensitive to power loss over long wiring runs than is DC. DCC has other long wire run issues with respect to control signal fidelity but those don't matter if you are only using the DCC system to provide power, not control. It may be simplest for you to use your existing DCC system to power RP equipment.

As Bill recommends, don't use your DC throttle pack to run microelectronic stuff. The power signature is way too dirty for microelectronics to tolerate for long.

[DaveB]

Question Bill.  Where is you power pack located on your layout?  What size wire do you use for your buss lines and how far apart are your drops?  I am building a new layout in a 36x15 room. It's going to have close to 200 ft of main line, a 28 ft switch yard with 8 tracks, several sidings and spurs.  I was thinking I would need 2 PRW-56's.

Bob..Do not try to run RailPro on DC.  I had an engine on a club track and they switched from DCC to DC with out me knowing it and I fried a module.  Some say it can work, I would't take a chance.

Dave

[nodcc4me]

Bob, DC power mucks up the track and wheels. RailPro is very sensitive to dirty track and wheels. The RP power supply does not do that. Just something to consider, unless you are willing to clean everything regularly.

[William Brillinger]

"Bob, DC power mucks up the track"

He means DCC here.

DCC apparently does cause track to become dirtier quicker.

Alcohol is commonly used to clean track and it also works against you, according to an article in MRH recently.
https://model-railroad-hobbyist.com/magazine/mrh2019-05/publishers-musings

Mineral spirits is a good choice for track & wheel cleaning, regardless of DC or DCC power.

[nodcc4me]

Yes I did. Thanks for the correction, Bill.

[Alan]

DCC apparently does cause track to become dirtier quicker.

I am glad you said "apparently" because physics doesn't agree. Nor do switch and relay manufacturers.

When you think about it, a wheel rolling on a rail is nothing more than two contacts of a electrical switch. For various reasons the wheel periodically loses contact with the rail just like an electrical switch opening and closing. If you accept the switch contacts analogy, consider that electrical switch and relay contacts have two load ratings - one for AC and another for DC. The DC rating is typically well below the AC rating. It has to do with zero crossing voltage which AC has and DC does not. AC arcs less than DC because the voltage across the contacts at some point is zero which breaks the arc. For a convincing demonstration: https://www.youtube.com/watch?time_continue=501&v=mQpzwR7wLeo&feature=emb_logo

We know powered metal wheels oxidize the rail in a teeny tiny spot every time there is a arc resulting from momentary loss of contact. The residue is zinc and nickel oxides i.e. black gunk. The oxides are of significantly higher resistance than the base metals. The mucked up track and wheels problem is real. No question about that.

The question of which causes more oxidation, DCC or DC is open to debate and warrants study before making definitive statements. DC should be worse. What blurs this assumption is the fact that DCC is an AC square wave, not a conventional AC sine wave. From the switch contacts' point of view DCC is effectively DC for 99% of the time and AC only during the 1% zero crossing time. Still, the presence of zero crossing is what minimizes contact arcing and DCC has it, DC does not.

From a practical standpoint, I don't believe the relative difference is worth your time considering. Basic track maintenance will vastly outweigh any ripples in your power supply or lack thereof.

• metal wheelsets
• run trains often
• graphene
• clean environment

[The_Dave]

Alan, I've read several of your posts here on the RPUG and I've learned something from each and every one of them. Thank you for taking the time to thoroughly explain things in exacting detail. Up until about 5 minutes ago I would have never known what I know now about AC and DC and how it requires different types of switches to work properly.

Thanks and keep the lessons coming!

[KB02]

Great responses, indeed. Stealing time from work right now, but I’ll have to check out that article about alcohol vs. mineral spirits. I have tried so many things and alcohol always seemed to have worked the best (even for cleaning off other cleaning agents).

Another question I have: I scratch built a turn table and round house. The turn table is powered by a simple 12v dc motor I hit off of eBay. Right now I control it with a basic decoder - my FCTC system thinks it is a loco that never gets above speed step 2. Would this be able to be powered by the accessory power supply? Or might I just be better off hooking up an old dc power pack just to control the turn table motor?

[Alan]

The AM-1 / HC has inbuilt controls for a turntable. Power everything from your RP power supply.

 

[Alan]

If you would prefer a more standalone solution use a reversible PWM controller in conjunction with a generic DC wall wart power supply. Probably get the whole affair built for less than $10.

Controller: https://www.ebay.com/itm/6-30V-DC-Motor-Speed-Controller-Reversible-PWM-Control-Forward-Reverse-Switch-M/181970823477?_trkparms=aid%3D1110002%26algo%3DSPLICE.SOI%26ao%3D1%26asc%3D20200116171858%26meid%3Dfd23eaddd92347c3b328bec31d29d38b%26pid%3D100008%26rk%3D6%26rkt%3D12%26sd%3D184172621674%26itm%3D181970823477%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DPromotedSellersOtherItemsV2%26brand%3DUnbranded&_trksid=p2047675.c100008.m2219

Your old school power pack is not a great solution if you need to operate the turntable motor at a slow speed. PWM will do a much better job of it. 

[nodcc4me]

I have a very old Atlas turntable being powered by a very old Postage Stamp Trains DC throttle pak. I set the speed once years ago with the rheostat and leave it there. The direction is controlled by a toggle switch on the pak. It works well but the darn turntable motor sounds like a buzz saw when I use it. I think you can hear it across the street. 
I couldn't justify buying another AM-1 just for that.

[KB02]

Another question: How sensitive are the LM’s to shorts?
While I do my best to keep things running well, derails do happen AND I have about a dozen Atlas snap switches which, in and of themselves, like to cause shorts with normal operation (only a couple real “problem children,” and I’m working on those).