Large Scale Central

USA Trains GP9

General Discussion
#1

I plan on getting a new USA Trains GP9 engine soon and would like your opinions regarding the upgrading of the locomotive (if necessary). Is the unit fine right out of the box or is it preferable to upgrade the wheels, gears, lights, or smoke unit to improve efficiency and longevity? Is it true that the loco draws a lot of current, especially with DCC installed? Should I get a 20 amp power supply? I haven’t selected my DCC yet, nor have I finalized the sound option, but I’m leaning towards the Phoenix.

I found George Schreyer’s recommendations on the web and I’m wondering if they are still valid or if they might be a little ‘overkill’ or outdated:

http://www.girr.org/girr/tips/tips5/gp9_tips.html Info from 2009 (updated in 2011).

I would appreciate your feedback on this engine and how it’s been running for you and what, if anything, you’ve done to it regarding maintenance and/or upgrading parts. Also your DCC preferences and sound for this diesel (even if you’re running battery power).

Thanks!

#2

They are among my best running engines, even after the sliders fall out because the cover plate tabs break off.

I’ve added Sierra sound and LED lighting, but it’s not necessary to replace the bulbs unless you want to run them from the sound system (as I do) or such.

When the axles crack on the wheels with traction tires, replace them with non-traction tire axles. From that point, and for the non-traction tire axles, use a brass sleeve (documented here) to fix them when they crack.

#3

The older units are power hogs, because they use incandescent lights. The newer units use LEDs, and are not so hoggy. The easiest way to tell which is which is… does your unit have a fan driven smoke. If it does, then you also have LEDs.

As to your next question, regarding DCC, I’ll let the DCC gurus answer that. I use Airwire, a form of radio control DCC, and am quite satisfied with that.

USAT has a problem with their axles splitting, I’m pretty sure that George addressed that. There are replacement drive gear/axles available on the market, but I’ve owned two for 15 years, and have yet to feel that need.

Phoenix is good for sound. It plays well with most receivers.

I don’t use smoke because of battery, but with the fan, it will put out a prodigious amount.

I like my Geeps, they are my goto diseasal.

Edited to correct Bill Gates

#4

I have had a set of CB&Q GP-7/9’s since they first arrived on the market… Only problem I have had with them, was one wire to the truck motor broke. Ran the units as track power for a few years, then converted them to battery and upgraded the lights to leds… One unit has had the phoenix sound system in it from the beginning, with a mini plug wired speaker in the second unit… They are great pullers, and have not had a problem with split axles on them, as of yet…

Since that time, I have acquired a few sets (B&M, Santa Fe) of the GP-7/9’s, and usually run them at every Operations session…

Just my 2 cents worth… (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-cool.gif)

#5

I am able to run the USA Trains GP9 on a 3 amp DC supply and after adding a decoder also on a 3 amp DCC program track.

So a 20 amp supply is not needed unless you are running 6 or more of these together.

Greg runs a PABBA set with lit passenger cars and did it with a 10 amp DCC system, so I see no problem with the smaller USA diesel engines.

#6

The incandescent lights can be replaced with LEDs for about $20.00 from USAT. Plug n play.

#7

RE: Replacing lights with LEDS

Hello Steve,

Did you need to install a voltage reducer to change from incandescent lights to LEDs - per USA Trains? Is USA a source that is unique to the lighting fixture, thus requiring their LED part(s)? I’m thinking of the other locos I have running incandescent bulbs.

Thanks,

Wendell

#8

Wendell, honestly, I don’t know. Take a look at the USAT parts page, that should give you the info you need.

http://www.usatrains.com/r22100parts.html. Items # 42 and 43.

#9

“I found George Schreyer’s recommendations on the web and I’m wondering if they are still valid or if they might be a little ‘overkill’ or outdated: ….”

Always be “valid” since the majority of units that his “recommendations” were based on are still out there running … not all in a landfill yet ! {Actually undec’d…} Even if you have one of the newer units there will be at least one “recommendation” that a unit owner might find useful, therefore not “outdated”, nor “overkill” :slight_smile:

btw, another GP-7/9 upgrades option write-up compliments of Paul Norton, on the OVGRS website; http://ovgrs.org/the-trains/battery-power-radio-control-and-sound/usa-trains-gp-9/ .

doug c

#10

Wendell;

You don’t need to buy parts for LED lighting from USTrains, you can purchase them from electronic suppy houses on line at VERY reasonable prices.

Installing them is the thing you need help with, and what LED’s you should be purchasing is the other question.

There are many many “Experts” on this subject, right here on LSC.

You can often contact them through posting a request on the electronics/electrical section of these forums.

One person that I know well, is Paul Norton. He is meticulous in his photos of how to do electrical modifications. His photos on how to do things are so clear, that you can do it yourself. NEVER A RAT’S NEST with Paul Norton.

He may have your answer on the OVGRS web page, at: www.ovgrs.org/ or he may see this thread and offer help.

Greg Elmassion is another great source of information…and there are others…

#11

I’ve had a chance to play with 2 of these recently and they are very nice.

#12

BTW, if you change out the headlights to LEDs, you need to use 3mm LEDs if you retain the existing lenses (that usually break on removal) and 5mm if you remove/break a lens.

#13

I have 2 GP-9’s UP. First thing I did was get rid of the rubber traction tires. Then after about ten year running them

with a battery car, I went to A/W onboard receivers.

Don

#14

Doug Cannon said:

“I found George Schreyer’s recommendations on the web and I’m wondering if they are still valid or if they might be a little ‘overkill’ or outdated: ….”

Always be “valid” since the majority of units that his “recommendations” were based on are still out there running … not all in a landfill yet ! {Actually undec’d…} Even if you have one of the newer units there will be at least one “recommendation” that a unit owner might find useful, therefore not “outdated”, nor “overkill” :slight_smile:

btw, another GP-7/9 upgrades option write-up compliments of Paul Norton, on the OVGRS website; http://ovgrs.org/the-trains/battery-power-radio-control-and-sound/usa-trains-gp-9/ .

doug c

I chose my words carefully, knowing they’d be closely scrutinized by somebody here. And sure enough! I hemmed and hawed a little bit before using the words “valid”, “outdated” and “overkill”. I’ll blame it on three bottles of Stella Artois for influencing my brash decision to use this vocabulary.

Yeah, “still valid” and “outdated” would apply to modelers who maybe bought a Gp9 in the past few years (post 2009-2011) after George’s article was written. There may have been rework modifications or part re-design by USAT recently that we don’t know about that subsequently corrected/upgraded the issues that George noted. Honest feedback on each of these issues would either heighten awareness or put any concerns to rest. That’s what I’m looking for. I used the word “overkill” not to offend George or anyone else, but to inquire within and get a consensus on which ones (especially the wheels) are really necessary to worry about at this point. For instance, I just don’t have the tooling available to upgrade the wheels and it’s nice to know I don’t really need to do it for many years down the road or until it breaks, so I won’t worry about it! I’m not a rivet counter so I don’t need to worry about changing out wheels because the wheel height doesn’t match with respect to the prototype. I’d obviously still like it to look good though, and am very receptive to detailing the engine. So far it sounds like the occasional split axel is part of the game, and LED’s are a must-change unless you pick up a newer GP9. Thus far the responses have been very valuable and I thank you guys here for participating!

#15

Wendell Hanks said:

RE: Replacing lights with LEDS

Hello Steve,

Did you need to install a voltage reducer to change from incandescent lights to LEDs - per USA Trains? Is USA a source that is unique to the lighting fixture, thus requiring their LED part(s)? I’m thinking of the other locos I have running incandescent bulbs.

Thanks,

Wendell

The USAT main circuit board shown in the parts list is marked as upgraded.

I have not seen one, but perhaps they replaced the voltage regulators with large resistors like they did in SD-70 and some other locomotives.

The LM317 voltage regulators previously used did not like the PWC output of the Revolution receiver. If the receiver output was used to power the USAT main circuit board for both motors and lights, the lights did not work.

I tried resistors in the light output leads of the Revolution receiver, but never found a value that would work with the USAT light circuits.

So I built my own.

GP-9 LED lights

I did remove the lenses from my GP-9s so I could use flangeless 5mm white LEDs. By mounting them 3/4 of an inch above the circuit board, they fit perfectly into the lens openings.

#16

Wendell, incandescent bulbs require regulated voltage… and there are voltage regulators in the older geeps.

LEDs requre regulated CURRENT, normally supplied by resistors… so you would discard the voltage regulators and pick appropriate LED current limiting resistors.

I have an entire section on LED lighting on my site and there are many tutorials on the net.

Greg

#17

The USAT GP9 is also a GP7!

If you realy interested in, read this: GP7 and view and compare pictures (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)

“GP7 has two pair of grills at the end of the long hood”

greetings from Germany

Thomas

XX

#18

A little hint … those traction tires work great in the winter plowing snow…(http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)

#19

A comment on George’s data on stall current and motors.

All of the measurements George did are accurate. USAT motors have an extremely high stall current.

You need to realize that the stall current is only realized at full stall, i.e. the motor not turning. This happens briefly as the loco starts to move.

When George was doing this, the decoders used did not have high amperage output transistors, and the stall current, however brief, was blowing up decoders.

Nowadays, most decoders use like 50 to 60 amps FETs… so they do not mind this brief stall current. Clearly they do not have the heat sinks to CONTINUOUSLY handle 50 to 60 amps, but it is not needed.

So this is why George warns about tens of amps of stall current, and Dan says his locos draw 2-3 amps. Both of them are right.

Greg

#20

someone correct me if I am wrong, but all the info on a GP7/9 also applies to the GP38 from USAT. at least the electronics.