Something I have learned over the years is that the metal shafts are machined accurately. Molds can wear or not be accurate.
The gears come out of plastic molding machines to my knowledge and the I.D. is not as accurate. Lower cost.
A friend worked at a company that did plastic molding and has some rejections, not gears. Depends on what is being made.
Someone at the MRH forums did measurements on Bachmann geared locos and found metal shafts OK. Some gears were cracked.
I think NWSL machines their plastic gears. Something to think about.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Climate doesnt affect it. Nor does age.
The plastic type they use (aka material) and the run time in my experience tends to be the biggest influencers.
Common HO locos with cracked gears/axles:
All Life Like proto 2000 steam locos, in particular, the berks, and the 0-8-0s. These are a pain cause replacement gears are few and far between.
Certain (older) runs of proto 2000 diesels, as mentioned above.
Athearn Genesis 2-8-2.
All Bachmann steam locos that used cheap white nylon for axles and gears (during the plus era or white box era)...they later improved their designs (blue box era) eliminating this issue but be wary when buying older equipment.
Older BLI steam that also used the cheap white nylon material for gears. (QSI paragon/powerhouse/PCM) Notably the PCM I1sa seemed to have these pretty common.
MTH first run K4s. (watch out for ebay listings with "non running" K4s, these are a gamble)
That list is atleast engines that I've had to replace/repair cracked axles from my experience. Each tend to be very common on ebay.
Charles
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Modeling the PRR & NYC in HO
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tstageI had read that the reason some of those older Proto 2000 locomotives were prone to cracked gears was because the press fit of the delrin gears over the axle was too tight and it stressed the gear; weakening it by creating microfissures in the material. That's a recipe for failure anytime. Tom
Well, finally after 20 posts the correct answer is posted.
Bernd
New York, Vermont & Northern Rwy. - Route of the Black Diamonds
protolancer(at)kingstonemodelworks(dot)com
Thanks, moved the decoder part over to DCC section.
Agreed. The NIB Proto 2000 GP7 I picked up a couple of years ago off eBay came with the infamous cracked gears. I just ordered the replacement gears from Walthers, popped the gear covers off of the GP7, swapped out the cracked gears for the replacements, pressed the covers back on, and she ran flawlessly. Not a difficult remedy at all for a handsome-looking locomotive.
I had read that the reason some of those older Proto 2000 locomotives were prone to cracked gears was because the press fit of the delrin gears over the axle was too tight and it stressed the gear; weakening it by creating microfissures in the material. That's a recipe for failure anytime.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
Personally cracked gears don't make a difference to me. Normally if you find one with bad gears, they go for cheap. And with $5 of parts and 10 min of time youll have a really sharp looking and smooth running locomotive. I would consider cracked gears one of the easier things to do on a P2K loco. Kinda like an oil change on a car
I have three Proto-2000 GP9s that did not have the problem.
Then I bought 1 GP7, and it cracked a gear.
I have no idea what causes it, but I just bought the pre-assembled Athearn replacement axle assemblies with those nice shiny wheels.
-Kevin
Living the dream.
Accually I fiqured I might do the one with decoder in the fuel tank for the NW2. Next question, to issolate the motor put tape under and replace screw with a nylon one ? We are getting way over my pay grade at this point in the learning curve. If I am correct, what size screw.
If you have a Dremel, the Kato NW2 isn't impossibly hard. TCS has some pictures:
| Train Control Systems (tcsdcc.com)
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
wjstix Well if the motor isn't isolated from the frame, the decoder won't work whether the engine is on the track or derailed(?) Anyway, I believe at least the later LL Proto engines were DCC-ready - my GP-7s came DCC ready.
Well if the motor isn't isolated from the frame, the decoder won't work whether the engine is on the track or derailed(?) Anyway, I believe at least the later LL Proto engines were DCC-ready - my GP-7s came DCC ready.
Everyone shortcuts it and says isolate motor from frame - the REAL thing you need to do is isolate the motor BRUSHES from the TRACK. The S1 has the bottom brush of the motor connected to the frame, but the frame is NOT connectect to either rail, it doesn't use an Athearn-style pickup. The pickups are isolated from the frame and are brought up from both trucks with wires. The problem is, if the loco derails, the truck pivots enough that a wheel could touch the frame - and if that wheel or another wheel on the same side is touching a rail, you now have the rail connected to the motor output. Poof.
There's actually more space in there than you think, the factory board it large, and even if you want to use an 8 pin decoder, removing the diode board opens up a lot of space. And hard wiring the decoder also removes the oversize 8 pin socket and board - which is huge to fit those silly plastic caps to hold the wires on. Not sure what would have been done int he past for a speaker, but SBS now has nifty curved sugar cube speakers that fit up inside the Alco cab roof contour. I figure on using one of those speakers and a v5 micro. I have extra space in one of mine - just as an exercise I put a Digitrax DH163L0 in it, and to get the shell to seat I had to file down some of the frame.
I have one of those Proto S1 engines. I have had it for some time, but as I recall the comments about isolating the motor are correct.
This was one of my first decoder installations. l recall that the inside of the shell was very cramped. I only put in a small motor decoder, and that was a squeeze. I replaced both front and read lights with much brighter LEDs, because the original incandescents had not light beam at all. The rear (cab) was also fed from the middle of the engine with a plastic light pipe, so I put the LED where it belonged.
Later, I had a sound decoder installed. Remembering the lack of space inside the shell, I had it done professionally. It's a Loksound decoder and I'm very happy with it. I have never taken the shell off to see how he did it.
It takes an iron man to play with a toy iron horse.
rrebellI have a Proto 2000 S1 that runs perfectly on DC and since it is DCC ready I was thinking about converting it and maybe do sound too (already have the decoder)...
Make sure you isolate the motor brushes from the frame before installing a decoder in your Proto 2000 S1. It says it's "DCC-ready" but it's not. If your S1 derails and shorts...your decoder can go *poof*.
I have two of the Walthers/Life Like GP7s from right after Walthers took over Life Like. Both engines developed cracked gears. Walthers sent replacement's, no questions asked. However, I think they ran out so that policy ended.
But, gear replacement is easy. It's done from beneath the engine and only involves taking the bottom cover plate off the trucks. You don't have to remove the shell or disturb any lights or wiring. I would suggest having a Q- tip and a tube of Labelle grease handy, because you'd might as well clean and lubricate the gear towers while you're in there.
Probably a combination of bad material, and poor aligment of the gears.
I buy clunkers of eBay to restore and the reason for most of them being on eBay is cracked gears. Allmost all manufactures have had some sort of problems with cracked gears and the fix for most is the Athearn gear. I had to go to NWSL for the Model Power red gears. I tried some gears off Shapeways and they worked but every one of them cracked after a few months.The only clunker I’ve bought that wasn’t restoreable is the Bachmann pancake motor, that is junk. The rest can be restored to as good or better than new. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
Ok, thank you. It was in the discard (sell) pile when I looked at it and noticed it was DCC ready (even though the box didn't say so). Out of all my engines that I really cared about only 2 are not DCC ready (Kato NW2's).
I think the weather theory had more to do with shipping rather than with the user. I recall someone saying the problem was the plastic gears fit on the metal axle very snugly, and big changes in temperature while the engines were in a shipping container on the Pacific caused the metal axles to swell, cracking the axles. Don't know if that's what really happened, but that is/was the 'weather' theory.
Anyway, if the Alco runs well, it's worth adding DCC/sound to. If it has trouble later, it's an easy/cheap fix to swap the gears for new ones. Since the old LL or Athearn "sintered" metal wheels weren't all that great, I've gotten new wheelsets with gears from Walthers and just swapped the whole assembly out on a couple engines.
https://www.walthers.com/replacement-geared-driver-assembly-diesel-wheelset-pkg-2-for-early-proto-2000-r-bl-fa-gp7-9-18-20-30-60-proto-1000-tm-f3
Worst case scenario is that you do the install, it breaks down later... and you fix it! Others seem to say that these gears are unlikely to break so I would go for it.
The climate question is intriguing. I guess if it got REALLY hot, the metal could expand and break the gear. I have never heard anybody report that, but it's an interesting theory for those who don't have complete control over the temperature of the train room (or garage).
Simon
I suppose it can happen to nearly anything, but the ALco switchers are not know for cracked gear problems.
It's also not a big deal, people seem to make it out like it's some horrible thing and the loco is permanently ruined. The most common ones for cracked gears are the GP7s. ANd I have 4 of them, because you can get them cheap - cheaper then the contemporary Atlas model, which has horribly coarse detailing in comparison. And it takes $3 in Athearn parts to fix.
Sometimes I think it got a bad rap when Walthers started requiring proof of purchase, meaning if you picked it up on eBay or from a table at a train show, too bad. But that was defensive - Life Like got themselves in trouble by pretty much freely handing stuff out. Athearn gears fir the P2K locos - guess what, the reverse is true. ANd P2K wheels are much nicer than the old sintered iron Athearn wheels. Life Like was sending complete sets with the wheels and gears as replacements for warranty claims, not just the gear. Oh hey, Life Like, I have 20 of your locos and they all have cracked gears - boom, wheels for your one broken P2K loco and your 19 Athearns.
Only one of mine actually had cracked hears, but when I had the loco apart to put decoders in, I swapped the gears with the Athearn parts.
The P2K ALco switchers do need some work to put a decoder in - they do not just plug in, not if you want to continue your streak of no bnlown decoders. You need a new orange wire running from the bottom motor brush (instead of running to the frame) and the bottom of the motor has to be isolated from the frame. You can run that new orange wire to the factory board, and then plug a decoder in, but the LL decoders with the resistors for the factory light bulbs will not fit without some frame milling. It's a good choice for a try at a slightly more difficult install without being all that tough. ANd they run great.
My guess is that age and climate might have something to do with it.
It's not only Proto locos, There are some runs of Athearn SD45, SD40-2, and SDP40 that also developed the problem.
Mike.
My You Tube
Not to worry. The S1 doesn't have the cracked gear problem.
Jim
Reason I ask is I have never had this problem yet I hear about it all the time. I have a Proto 2000 S1 that runs perfectly on DC and since it is DCC ready I was thinking about converting it and maybe do sound too (already have the decoder), but the cracked gear thing could make me reconsider.