A forgotten Athearn SDP40 looking for some “love”..

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flightops

Active Member
The SDP40 I picked up off ebay for 25 bucks showed up today. Well, 25 bucks to purchase, more like 65 bucks once shipping was added. Still, it was worth taking the risk to me based on the pictures.

Not an expert on this stuff by any means, but I believe this is whats known as “blue box”:

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This is obviously someone’s collection of bits (likely an estate sale box lot thing) as the end of the box is hand written in marker “gp 40 Dummy”:

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If I use some magnification, it looks like the first stamped letters crossed out are “F7A”. The rest are mostly illegible.

Inside is three sheets:

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They had listed it as the “trainamaster”. But at least it had an SD40-2 sheet in it:


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And the diesel itself:

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All there, all intact. Looks like someone painted it and used waterslide decals as the white lettering is crumbling and turns to dust if even grazed.. Paint looks well done at least. I sides of the shell is all black plastic. Or at least it looks like black plastic, it might be sprayed black..

I pop the shell off for a look:

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Little corrosion here and there but it looks complete. I’ll (obviously) give it a full teardown, cleaning and re-lubricating.

As a quick test, I drop it on a section of track and try it. Starts right up. Quiet and smooth. Crawls super slow with just the lightest touch of power. Even the little light bulb still works.

And it’s HEAVY! At least it’s a lot heavier than anything else I been running (admittedly, not much prev experience with “hobby grade” stuff).

The “flywheel effect” when trying to stop is new to me. Run the front trucks off the rail end the first time as I’m used to the pancake diesels stopping on the spot when power is low/off. I adapt to it easily after that first stop and no further issues.

I’m probably going to repaint it in CN livery. From what I can gather, CN only ever had two SDP40’s. They ran lots of SD40-2’s, but next to no SDP’s. Thats ok by me though, this is just more of a fun thing than a historically correct exercise.

Its going to be a good runner when I’m finished I think. I think I did ok for $25, even if it did end up at $65 to my front door.

If the first little bit of running it had right out of the box is any indication of the step up to “hobby grade”, I may be done running “pancakes” from now on.

Well, maybe “pancakes” xmas morning still might be nice….;)
 
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Just so you don't get confused, that SDP40 has absolutely nothing in common with an Athearn SD40-2.
Another heads-up: Those white rubbery motor mounts will crumble t dust as soon as you try to mess with them.
I don't know about your soldering skills, but replacing that steel strip that goes across the top with soldered wire will help a lot in the reliability department.
 
Ah yes, google reveals a different “parts” sheet:

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I’ll look closely at those pads before doing anything with them.

“Soldering” shouldn’t present a problem. If I can work on helicopters and supersonic aircraft wiring/electronics, its reasonable to assume a model train is “in my wheelhouse”...;)
 
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Yes, Athearn Blue Box models are great runners. They last a long time too! 👌👍
You can also do some "Super-Tuning" to make them run even better. But they are good as is most of the time.
 
Taken apart, cleaned, polished the contact areas and re-lubricated:


That's now running off the MRC Tech II 2500 that just arrived today.

I threw that car on there just so it was pulling something.

Seems to be a nice runner to me.

:)
 
Yes, Athearn Blue Box models are great runners. They last a long time too! 👌👍
You can also do some "Super-Tuning" to make them run even better. But they are good as is most of the time.
Not to be "that guy", but in that video the guy says at the end (after going through all the "tricks") he thinks that "super-tuning" is a myth:

myth.jpg


Hmmmm..... :rolleyes:


I do see some "reliability value" in installing a jumper wire from the truck to the motor contact plate though. Certainly would cut down on the arcing between the truck contact and that long steel spring and help with continuity/lowered resistance.
 
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Yeah I know, Right? But If the model is ever missing the top contact or is rusted (Both I have experienced) it can work as a fix.
Anyway, It looks like your model IS running fine. 👍 As stated, Athearn Blue Box models are great runners.
 
Yeah I know, Right? But If the model is ever missing the top contact or is rusted (Both I have experienced) it can work as a fix.
Anyway, It looks like your model IS running fine. 👍 As stated, Athearn Blue Box models are great runners.
Yep. I took a little "extra liberty" and added a light touch of silicone grease (ie: plastic safe formula) to the axle bearing surfaces, the truck internal gear spindles and the slip-joint and universals on the drive shafts. Just a light touch.

Quieted the whole rig down quite a bit.
 
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Yep. I took a little "extra liberty" and added a light touch of silicone grease (ie: plastic safe formula) to the axle bearing surfaces, the truck internal gear spindles and the slip-joint and universals on the drive shafts. Just a light touch.

Quieted the whole rig down quite a bit.
That's exactly what I do! 😃 Oil works too, but for the longest grease was all I had.
 


Athearn actually calls for “oil” on the truck gears axle shafts.

I prefer the silicone grease on all plastics as opposed to “oil”.

My Dual turntables, however, call for Shell brand Gadus grease on plastic parts so thats what they get.
Not that you asked for any advice, but I use Mobil One full synthetic motor oil, 5w20. It's synthetic, doesn't smell funny, and is an excellent lubricant. A single drop is usually all it takes. And if you wonder about using it on plastics, I can't think of any modern automobile engine that doesn't contain more plastic than is in an entire fleet of model locomotives. And of course it's very low friction.
 
Not that you asked for any advice, but I use Mobil One full synthetic motor oil, 5w20. It's synthetic, doesn't smell funny, and is an excellent lubricant. A single drop is usually all it takes. And if you wonder about using it on plastics, I can't think of any modern automobile engine that doesn't contain more plastic than is in an entire fleet of model locomotives. And of course it's very low friction.
No worries.

The problem with discussing lubricants and plastics is the word "plastic" itself. There's so many formulations now that the generic word "plastic" just covers too much.

Plastic originally meant "formable/moldable", and IMHO, that's where the definition should end. It's far too overused these days in common references for materials that are, quite frankly, very different.

Modern vehicle engines use formulations of "plastic" that is very different than what was available in the 70's (IE; when this little model's parts were made). Now there's everything from simple polymer plastics to Delrin and UHMW plastics. Valve covers, thermostat housings, timing chain guides, etc. Even gears in some applications. But it's specifically formulated for use in oil baths and wear/friction applications. Virtually none of it is no refined from mineral oil, which is the issue with plastic and oils.

Heck, my snow plow blade edge is now UHMW plastic and it wears almost like steel without marking up my asphalt driveway, my corvette is considered mostly "plastic", I machine Delrin the same way I do aluminum, my F150 and Mini Cooper use more plastic parts than can be counted. "Plastic" has come a long way.....but it's so varied now, they almost should drop the word "plastic" altogether. It's nothing lke the "plastic" was when the word became popular in the 50-60's.

The 70's stuff was barely out of the "Bakelite" generation of plastic formulations, (which was basically a thermo-setting phenol/formaldahyde resin) so it's highly likleythese models aere refined from mineral based stock. Virtually all the early thermo-plastic fomulations were. That changes how you should be dealing with it compared to modern plastic formulations used in modern vehicles and other such heat/friction/oil bath applications.

Mineral oil, derived from crude oil through the refining process, is predominantly composed of paraffinic, naphthenic, and aromatic oils.

Synthetic oil typically comprises paraffinic and olefinic oils, with a minimal inclusion of naphthenic and aromatic oils..

Now, synthetic oil isn't a bad choice for older plastics because it's essentially olefin based, which is much less reactive with early plastic. It's the naptha and aeromatic components in mineral based oils thats the issue. Early plastic fomulations are more likely to have been refined from mineral oils. Reintroducing mineral oil napths and aeromatic components to plastics that were refined from mineral oils can have effects from crazing, embrittlement or just plain making it "gooey-er" again.

In summary: you need to now what tye of "plastic" you're dealing with before introducing a type of lubricant to it.

That's mainly why I try to stick mostly to the silicone based oils/greases when dealing with old/early/unknown formulations of plastics.....minimal interactions with mineral oil based plastics.

;)
 
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And all the above is why I only use Mobil One, it doesn't have any petroleum-based carriers, like nearly all other brands. When people see "synthetic" oil, they think it's pure synthetic. It isn't.
 
And all the above is why I only use Mobil One, it doesn't have any petroleum-based carriers, like nearly all other brands. When people see "synthetic" oil, they think it's pure synthetic. It isn't.
Yep, gotta read the label and understand the base stock information.

Virtually all "synthetic" oils start out as distilled crude.

Distilled crude is chemically altered to be more olefin based than aromatic oil based. That's also why synth oils will always contain some minimal amount of naptha/aromatics.

Sometimes materials like coal are used, but always a carbon based product of some sort left behind by the little plants and microbes since life first formed on the planet. It's just a matter of what stage they are at in the march towards becoming actual crude oil.

But using something besides crude as the base is a "have no other choice" type of thing as using substances other than crude raises the production costs exponentially. Germany used coal in the WWII era to make synthetic oils, but it was very costly. Much more costly than starting with crude oils. They had no choice though as they had virtually no domestic oil sources but abundant coal reserves. And we all know why they needed oil......it wasn't exactly driven by "domestic" consumption.......:rolleyes:

The bigger issue with oils intended for internal combustion engines is the additive package. There's anti-foaming agents, detergents, viscosity and friction modifiers and any other number of modifiers intended to deal with combustion byproduct contaminants and the internal combustion engine operating environments. They can be harmless to simple mineral based thermoplastics (70's era), or they may "attack" them. Only way to find out is to try them, since you don't know the original formulation used in the "plastic" or whats in the engine oil additive package.

I normally recommend "non-detergent" (ND) synthetics oils over "engine" oils when dealing with plastics or a "non-combustion environment" use. Simple enough to find, you just look for ISO/air tool oils;

SAEISO/AW
10W32
15W or 20W46
20W68
30W100

They're straight weight oils and no additive packages. Well,, they might have something like an emulsifying additive package, but still about as minimal additives to it as you are going to get. Just be sure to buy the synthetics vs mineral if used on plastics. It's just less likely to interact with the plastic.

10W/ISO32 is what most people would need for these little models, sewing machines, etc. I use ISO grades in my machine tools for bearings and gears as well as when cutting and also on things such as my vintage turntables, sewing machines, etc.

Then there's also the virtually never-ending list of silicone lubricant products. Grease, paste, sprays and liquids.

There's even some special use products like Bentonite grease which is actually a clay based vs soap based. It literally is a clay carrier. I've got a bottle of it out on the shelf for some very specific uses. None of it is model train use though....lol!

Oils and lubricants. Fascinating subject. It's an entire science unto itself. More to know about them than there are grains of sand on the beach.....

:)
 
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Oils and lubricants. Fascinating subject. It's an entire science unto itself.
Indeed, they are truly fascinating. Especially to an old and outdated mechanic like me.

Thank you for taking the time to share all of that and the discussion about plastics. Both topics are worthy of a dedicated thread.
 
I have a Blue Box SDP45 myself in EMD blue/white, still strapped into its box from when it was made many many years ago, doesn't fit in with my modelling locations or era's (it is not even that accurate to a prototype to be honest) but I just liked it. Hopefully it will take its place on the workbench one day.
 
Well, time had come to box it all up again.

The whole smash is going ntto hibernation for a while so we can get the house cleaned and organized. It was just a loop of test track anyways.

Never fear though, part of the re-jig of the house is cleaning and clearing the storage room, which will provide the space for the 4x8 train layout.

I’ll probably be “going dark” until we’re done.

:)
 
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