Advice on an Athearn Blue Box GP9

[Keith Addenbrooke]

A couple of years ago (Nov 2000) I bought an Athearn Blue Box GP9 in Santa Fe ‘bookend’ livery for a project I was exploring at the time:

 

 

It’s been in storage since then, as the space I could use for modelling changed and switching to Narrow Gauge made more sense (HOn30 and H0e).  I’ve also had fun looking at other scale / gauge combinations too, and have various threads dotted around RMweb devoted to them.

 

But with the possibility of doing something simple in American HO having recently re-emerged, I’ve unpacked the Geep to see how it’s doing.  These locomotives have long been recommended for beginners (like me), and removing the body shows why:

 

 

There are no wires or soldered joints, and all electrical contacts are through heavyweight contact strips - pickup is via the wheels on one side.  Both trucks are powered, but the motor fittings (and other parts) are slightly asymmetrical, making it very difficult to reassemble it incorrectly.

 

It’s basically a very robust mechanical model that should last for ever - and with the dual flywheels can run very well even by today’s standards.

 

What’s my question?  The problem is the loco seems to have a “clicking” or even “slapping” noise when running - the kind of sound I’ve only heard before with steam locomotives that need their motion adjusting or lubricating.  To make things worse, at times the trucks almost seem to ‘jump’ - suggesting to me something is either binding or catching, or possibly some of the plastic gears have split, as it’s an older model.

 

But having disassembled and reassembled it all, I’m mystified as to where the problem is, and am wondering what I’ve missed.

 

I started with the trucks.  The sides are push fitted so come off easily.  The worm gear housing also in clips to free the trucks:

 

 

The wheels are freed by unclipping the truck plate underneath, and the trucks then disassemble by removing the small clip on top:

 

 

 

I couldn’t see anything wrong with the gears though (on either end - just one shown for brevity):

 

 

 

The only thing I could find were some tiny joins along the axles - are these part of the manufacturing, or have all four split?  Two shown here in close up - the other pair were the same:

 

 

What makes me think these may not be the problem, is the way I can easily - and noiselessly - push the reassembled trucks along a track:

 

 

I did have to adjust the back-to-backs ever so slightly to reduce the friction with the truck sides, and added a tiny amount of lubrication to the wheel bearings.  Both trucks now glide very smoothly along the track.  I therefore turned my attention to the motor and cleaned as much gunk off the commutator* as I could (using a toothpick to get into each of the grooves).  To be fair, it was all quite clean really given its age:

 

 

The brass strip on the top up clips to give access to the upper brush, which is positioned vertically (not visible).  A second brush is also vertically below the motor and is also held on with a similar clip - the left hand end of the brass clip is just visible in this photo.  I did take apart the top brush but couldn’t see any problems with it so didn’t try the lower one.  The components of the worm drive also seem in good condition, with no signs of splits and all universal joints moving freely:

 

 

The motor runs very freely when the worm drives have been removed (note the brightness of the lamp):

 

 

So it was only when everything was reassembled that the problems re-started.  My non-expert guess would be that the worm gears aren’t properly sitting on the cog wheels in the trucks for some reason, but I can’t see a way to check this with the cover off?  Any ideas anyone?

 

I’ve had the locomotive gently circling a test circuit, and it starts and runs much slower than before I serviced it, so at least that has helped.

 

I’d also value any advice on couplings - this locomotive came without any (which I knew when I was buying it).  I’d like to fit standard Kadee couplings - I don’t need magnetic auto-uncoupling - but my guess is a model of this age would have come with horn hooks fitted originally?

 

 

Apologies for the long post for what I hope is a straightforward question.  I think I may be missing something obvious as a novice here.

 

I’ve noticed this is my 2,000th post on RMweb since joining in Nov 2018: it’s nice to reach this milestone with a practical post.  Thanks, Keith.

________________________

(* I’m very much a beginner when it comes to locomotive maintenance - if the Commutator is a different part altogether it just shows how little I know).

 

Edited October 30, 2022 by Keith Addenbrooke

[long island jack]

looks like cracked gears is your problem, clicking is the classic give away, you need replacement gears or try super glue and baking soda!

[Keith Addenbrooke]

8 hours ago, long island jack said:

looks like cracked gears is your problem, clicking is the classic give away, you need replacement gears or try super glue and baking soda!

Thank you - it looks like this may be the problem after all - the only cracks I could find were on the axle muffs.  Not sure what the baking soda is for though: is it for cleaning?  Keith.

 

[long island jack]

 

[PaulRhB]

2 hours ago, Keith Addenbrooke said:

Thank you - it looks like this may be the problem after all - the only cracks I could find were on the axle muffs.  Not sure what the baking soda is for though: is it for cleaning?  Keith.

 

Those cracks are definitely the problem, clicking is as mentioned above the giveaway sound, you can see the jagged edge too. To try and repair these will mean closing that gap back up and the problem is the slippery plastic doesn’t stick well with superglue, I’ve only managed to repair similar types by turning up an outside sleeve but I’m not sure there’s room in these trucks.

The axles are standard though so try a bit of searching to check as Athearn 60024 drive axle gears appear to be the same, although labelled for the SD40, and also A-line 40005 gears sold as replacements. The only issue with spares is the postage!
 

[Allegheny1600]

Hi Keith,

Your problem has already been identified and solutions suggested but may I add that if you do try and repair the split axle muffs, for superglue to stick, it is imperative that the joint is clean, dry and FREE FROM GREASE AND OIL!

For me, I use a, long impossible to obtain, wash of carbon tetroclorate (nasty stuff!) but I suspect a soak in methylated spirits should do the trick.

HTH,

 John 

[long island jack]

this maybe be a better option 

https://www.anglo-americanmodelrailways.com/product-page/athearn-f7-gp7-front-rear-power-truck-assy-402011-ho-part

[John M Upton]

I concur with everyone else, your classic cracked gears on the axles (more common in my experience with Proto 2000 Geeps but Athearn are affected too).

 

I have tried gluing cracked gears in the past but only as a very short term solution to get a loco moving whilst awaiting parts.

 

Fortunately replacement gears are an easy swap out, finding some in the UK however is much more of a challenge. 

 

Worst comes to the worst, I may have some I can let you have if you have no luck elsewhere. 

[2E Sub Shed]

20 hours ago, Keith Addenbrooke said:

I’d also value any advice on couplings - this locomotive came without any (which I knew when I was buying it).  I’d like to fit standard Kadee couplings - I don’t need magnetic auto-uncoupling - but my guess is a model of this age would have come with horn hooks fitted originally?

 

Just one thing to be aware of that you have probably spotted, these Athearn locos have one side the track supply connected to the chassis.

 

Therefore, it may be worth considering using a plastic coupler such as the Bachman EZ-Mate to prevent a short if using with other Blue Box locos. - See Blue Box loco issues

 

DCC Conversion is a bit of an issue as the motors in older models can have a high current draw amongst other issues.

 

Agree with comments re spares, since the closure of Model Junction in Slough, finding spares for US models has become harder, no one seems to stock spare wheel sets in UK, and have bought several S/H models at shows which needed them.

 

 

[Barclay]

They run very nicely with those huge brass flywheels so definitely worth repairing. To improve pick up reliability that spring steel strip that makes electrical contact between trucks and the motor can be removed very easily and short lengths of wire soldered from truck to the copper strip at the top of the motor to give better continuity.

[John M Upton]

Those old Athearn motors are pretty much bomb proof, be aware of the older ones though, generally have a more grey look to them, in fact they look like this:

 

These have a very high current draw and can cause some modern controllers to cut out.  This example also demonstrates the hard wiring mentioned earlier.

[Keith Addenbrooke]

Thank you to all for the wisdom and advice, with particular thanks to @long island jack for pointing us towards the Baking Soda video - it’s quite amazing / frightening what that stuff can do (given that we can eat it): it came up in discussion at home last week in connection with removing melted ready-meal plastic from oven trays too!

 

Definitely worth trying a repair - I’ve also been advised Mech Models in Burton may stock some suitable replacements, cheaper than the complete trucks at Anglo-American.  Means I can try a repair knowing there’s a back up if I bodge it.

 

DCC conversion is not an issue for me, but a good point worth noting from @2E Sub Shed, thank you.  Not sure when I’ll get round to trying this, but I’ll post the results to show how I get on.  Thanks again, Keith.

 

Edited November 3, 2022 by Keith Addenbrooke

[long island jack]

good luck hope it works, let us know how it works out, those replacement wheels from Mech's, are better than stock Athearn, there nickel plated.

[alastairq]

Not too sure of gear sizes when comparing the athearn SD series with the GP9[meaning, I'd have to conduct a search to find all mine]....but there may also be the option of shapeways?

 

https://www.shapeways.com/shops/dkrickman

 

 

 

[Luigi Taveri]

Hi Keith

 

With regards to the query on the couplings, it does look from the photo as though the (a?) previous owner has done the hard work for you and filed the coupling mount to the correct height, and all you need to do is mount a kadee no5 in a standard box ( possibly using a 2-56 bolt or the BA equivalent)? 

 

Foxy 

[Keith Addenbrooke]

On 13/11/2022 at 20:46, Luigi Taveri said:

Hi Keith

 

With regards to the query on the couplings, it does look from the photo as though the (a?) previous owner has done the hard work for you and filed the coupling mount to the correct height, and all you need to do is mount a kadee no5 in a standard box ( possibly using a 2-56 bolt or the BA equivalent)? 

 

Foxy 

Thank you, that’s really useful.  I also have some freight cars which need couplers fitting (or changing) so I’ll have a job lot to do at some point.  Helpful to know I can leave the coupling mount where it is on the Geep, Keith.