Installing RailPro in a USA Trains Alco PA-B

[rsmproductions]

Happy New Year Everyone!!

I am helping a friend with an install of a RailPro module in both of his USA Trains Alco PA unit and B unit.  I've only experienced installing in one of my LGB Forney's which actually went fairly well.  The PA-B units are currently wired with Airwire 900.  There is a PC board that controls the front lights - cab, headlight, and two number lights.  Do I need to remove this board completely and wire each light directly to the RailPro?  There is also a smoke unit but I don't see any reference in the RailPro instructions about that. 

I would appreciate any help you can give.

Thank you,
Richard

[trainman605]

First, one Rail Pro Module will handle both the PA-A and the B unit, so two modules are not needed. You will just need to MU the two units together with a wiring harness, I would also have a wiring plug between the two units so you can disconnect the two. You can also have lights and a speaker in the wiring harness, so a 8-10 wiring harness would probably be needed tor all the different connection needed. I would remove all the Airwire 900 system as none of it will be needed with the Rail Pro System, plus I would replace all lights with 3mm or 5mm LED's 12v with resistors sold on eBay, I use the 5mm LED's for headlights and the 3mm for all other lights. Just remember when wiring the trucks to use the F & R module power outlets and it then the same on the other unit, so all trucks will run in the correct direction. I find Rail Pro is pretty much a pretty easy system to wire, just follow the wiring diagram included with a new unit. I thought I answered this question on another forum, but not sure.
trainman

[gregeusa]

I have a few comments. First I have a number of USAT diesels that I run in consists.

I have an ABBBA PA set.

If you start pulling long trains or have grades approaching 2%, I'm pretty darn sure the decoder would not handle 2 locos, so it would make sense to measure your current draw on DC ON YOUR LAYOUT and grades and your trains, before trying to share one decoder among 2 of these locos.


USAT uses overly complex wiring to lights, because they use different voltages, and most are incandescent. That said changing out the PA to LEDs is a BIG task, and getting things like number boards to look better than a bunch of squirrels with flashlights is tough with LEDs in this case.

I would actually work on getting dropping resistors to power the existing lights, but you need to measure voltages on the various lights BEFORE you rip stuff out.

The smoke units came in 2 versions, one a small boiler type that run on about 5 volts, and the other powered heater and fan, and they have their own regulator board.

My best advice is remove the Airwire, but leave the factory boards. Depending on your battery (I'm guessing you are going battery), using the existing lights and the REGULATORS in the factory boards would be easier.

Go to my site for more details on the PA

Greg

[trainman605]

Like I said in the previous post one Rail Pro board controlling two locos would work is because I talked with Don at RCS and I asked if one board would work for an LGB F-A unit and also an F-B unit and he said, one board can control two engines. Now if you are talking about more then two locos and using one board that could be too much draw for the one Rail Pro module. I have not done the LGB A & B units to date, but I do have Rail Pro in three of my engines to date.
trainman

[JRad]

Will it work; sure, so long as you don't overload the Loco Module.

Is it a good idea?  Not in my opinion.  If you want lights and sound in the trailing loco there are too many wires required between locos.  Only two wire for just motors, but the whole point of RP is the enhanced control. Also, the locos need to be perfectly speed matched.

Modules is every loco solve those problems.

[gregeusa]

Stating that since Don Sweet says one decoder can run 2 LGB locos is way different than 2 USAT locos.

Clearly neither party involved knows the famous current draw of USA Trains, or that for years a DCC decoder manufacturer only warranted their 8 amp decoder in USAT locos, not the 4 amp unit.

LGB locos are famous for their low current motors, often averaging 1 amp each or less (notice the 1 amp power supply in LGB starter sets).

Now come to USAT, notice they sell a 10 amp transformer. They are equally famous for their high current draw and high stall current motors.

You need to research the actual loco, but this will do:
http://girr.org/girr/tips/tips12/usa_f3_tips.html

What is the warranty on RailPro?

Greg

[trainman605]

True, I do see where like locos (same brand and motors, etc) would probably work regarding power needs for each loco, but different brands would not work as you would have no way to adjust power requirement for each engine as you only have one module to work with. If I wasn't only using LGB engines of like power units then I would most likely put a module in each loco as it would be the only way to adjust the power needs for each loco with a module in each. The original question was for FA and FB to run together, both same manufactured engines being the same, now changing that engine arrangement would be a total different scenario.
trainman 

[gregeusa]

My point is that 2 USAT locos is most likely over the capability of the RP decoder. Get one per loco.

The USAT locos are 2 to 3 times the current in normal running and maybe 10-20 times the stall current.

Greg

[rsmproductions]

Greetings Gentlemen,

I appreciate all of your suggestions.  Sorry I have not responded back until now (months later).  I am a teacher just finishing 31 years and haven't been yet able to regulate career life with my hobby of garden railroading  .  The USA PA-B is still on my work bench.  Thankfully I have a fellow railroader that is patient.  I'm hoping to get things running this week.

Richard