General > General Discussion

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

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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:

--- Quote from: William Brillinger on February 17, 2020, 03:12:28 PM ---
DCC apparently does cause track to become dirtier quicker.


--- End quote ---

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!

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