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When I read about gearbox problems I can't help but get a little aggravated.  Lobaugh, Max Gray, US Hobbies had O scale drivetrains figured out by 1960.  Smooth, quiet operation at single-digit speeds without speed control.  Top-quality materials and construction.  If you've never seen one you owe it to yourself to check one out, or better still, take it apart.  Heck, on the 2-rail forum they are discussing drives built in the 1920s and 30s that are very serviceable and still run great!

The bottom line is that except for Williams and Weaver circa 1990, NONE of the 3-rail manufacturers wanted to tool up for a separate gearbox, split chassis with removable wheels and axles, etc.  But that's the "right" way to do it!  Everything else, including the vaunted 700E, was compromised either for cost or ease of manufacture.  There are a few exceptions: Lionel's JLC (pre-Legacy) Y6b is very well made, and I think the Niagara has a two-piece chassis and true gearbox.  Ironically all of MTH's HO-scale locos are made this way.  So it CAN be done in die-cast.  But our beloved O gauge importers choose not to.

There's nothing inherently wrong with back-drivable gears or an idler gear drivetrain.  If it allows additional gear reduction, it's a good thing!  It comes down to the quality of the materials and the execution, tolerances, etc.  In the case of the H10 photos above, I would do something like the "bread clip mod" to keep those gears centered and fully engaged.  Also keep a close eye on lubrication.  But if the tolerances aren't right then yes, the drive will eventually eat itself and there's nothing you can really do about it.  All the more reason to make the gearbox or intermediate gear a separate and replaceable part.

The small front-leaning motor in the boiler is its own issue, independent from the gearbox.  I guess this configuration was supposed to make it easier to fit electronics in the loco (which is a bad idea to begin with!)  A larger motor will always deliver more torque, and on a steam loco the largest available space is in the firebox.  Lionel corrected K-Line's mistake when they reissued the Lima A1 Berk.  IMO they should have redone the Pennsy K4 and Mikados in a similar fashion.  But instead of asking the hard questions people keep buying them, so...    That's exactly why threads like this are valuable!

Last edited by Ted S

Ted, there’s nothing wrong with the simple worm on worm wheel set up .....be it 16:1 or 20:1 ....Cruise is here to stay, and 99.9% of us are glad about it....buddy, you’re in a minority of minorities....and unfortunately, out of the box, that CC Niagara is the worst engineered pile of poo to ever roam the rails!...you can’t buy one without first having to rip it all to pieces and rebuild the driveline!...and taking it apart...( I’m sure even Alex will attest to this) step1: call all your friends and tell them you’ll be busy for a long, long time.....you got to gut a toolbox to fix that thing....once rebuilt, it’s a good runner....but good golly, don’t use that abomination as an example.....

Pat

@Lou1985 posted:

I'm not familiar with Lionel's latest gearboxes, so I assumed that all the Legacy backdriveable gearboxes were the same. All of my steam except one locomotive is MTH Premier with the large worm/wormshaft gearbox that's pretty bullet proof. Any of the Legacy stuff I've seen first hand has had that little intermediate gear setup. 

First gen legacy stuff does not have the extra gears i.e, the first run Legacy FEF,scale NKP, PM, and C&O berks, Legacy PRR M1b to name a few. The VL hudson doesn't have it either. They are all back driveable.

This "new" gearbox first appeared in the original Legacy K4 back in 2011. Since then its gotten more common, but there have been a few exceptions like the K Line tooled Legacy s1 berkshires, the Legacy ESE Hudson and the VL Niagara and likely a few others.

 

The recent Legacy H10 only has a 16:1 gear ratio, so clearly it just uses the worm on the drive gear.

Unfortunately, thats not the case. The photos I posted earlier are of the H10 gearbox.  

It also has the intermediate shaft visible behind the spokes of the driven axle . However it has the luxury of the removable bottom plate( a carry over from the TMCC tooling) so you can see whats in there:

Lionel Legacy H10 gearbox:

001002 

 

 

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Last edited by RickO
@RickO posted:

Unfortunately, thats not the case. The photos I posted earlier are of the H10 gearbox.  

It also has the intermediate shaft visible behind the spokes of the driven axle . However it has the luxury of the removable bottom plate( a carry over from the TMCC tooling) so you can see whats in there:

I took my H10 apart, Lionel 6-84948, and four rotations of the flywheel results in 1/4 turn of the drive wheels.  I don't know how you compute gear ratio, but that's how I compute it.  I didn't take the motor out, but it certainly does have a 16:1 gear ratio!  I don't know exactly what the gearbox looks like inside as I haven't had it that far apart.

I wasn't questioning the gear ratio John. I was just pointing out it has the more complicated gearbox design.

It doesn't have to be taken "that far apart".

Remove the pickup rollers and the 3 screws on the bottom that don't say "grease" and the whole bottom cover of the chassis comes off with the brake shoe detail.

So easy. Even a caveman like myself could do it.

It's actually a really nice design from a maintenance stand point ,if it weren't for the extra non serviceable gears.

 

Last edited by RickO

I'm well aware of the problems with the first (CC) Niagara.  I believe they were solved in the recent Vision release.  I mention the Niagara and Y6 to emphasize that some O gauge locos have been made with a split chassis and separate gearbox, so it's technically possible.  The actual performance depends upon the execution: materials, tolerances, etc., and that's where the problems came in.  Of course those examples are only available to those blessed with O72 curves.

The use of an idler gear can reduce the gear ratio-- or not.  Northwest Short Line (NWSL) used to sell driveline parts and gearboxes for upgrades, custom builds, etc.  The most appropriate gearbox size for O scale applications was "0.6 mod".  This gearbox was sold in an idler and a non-idler configuration.  The gear ratio on both was 23:1.  The idler vs. non-idler choice was more about driveline angle (or making the driveline less visible so that it doesn't spoil the appearance of the model.)

There's a discussion on groups.io (originally Yahoo groups) called "Repower and Regear" specifically dedicated to stuff like this.  The majority of the posts are about HO & N but the principles are the same.  There are occasionally drivetrain discussions on the 2-Rail Scale Forum here at OGR, and on other 2-rail Forums around the Web.  How many of you have explored outside the world of 3-rail O gauge?  I have done so regularly for more than 20 years, and based on what I've read we're being short-changed.  The fact that all of MTH's HO locos had the design I'm asking for from Job One, is because that audience wouldn't have accepted them otherwise.  Learn, ask the hard questions, and demand better.  Let's work together to improve the breed!

Last edited by Ted S

Ted, when we’re discussing the higher echelon models, the platforms from what I like to call the “Pittman era” all work just fine for just about all of us....these platforms rarely suffer a breakdown, and the gear ratios work perfectly with the motors designed to run them.....and cruise control just makes them that much better.....PS2, and Oddesy were amazing advancements, albeit now it’s archaic to what’s been done...32 steps became 100, Oddesy lurch has been solved, and it’s to the point where even a novice can swap out a driver in anything Oddesy equipped....the motive power I’m describing above are robust, powerful, and rarely see a mechanical failure...the problem I see is with Pittman pricing themselves right out of the market, the mfr.’s now are left with proven platforms, but crappy motors....so their scrambling to make things work with what’s available..proven point, I have a Lionel Legacy that had that horrid Cannon motor...problematic from the word go...a motor swap cured all its woes....the point I’m trying to make here for you to see my view ( and many others )  .....to achieve the most realistic operation, and realism, any electric motor is going to need reserve power on tap so it can be pulled from at any given moment...the technology has come along ways that you can’t even tell it’s happening....if you’re all conventional, and your track is at let’s say 10V, that’s it....the motor is at 10V and there’s no more....anything and everything that gets in the way that produces the slightest drag, or tug increases amp draw, and requires additional voltage ....I know you know all of this, and this is intended for those that don’t......it’s all about low RPM, light amp draws, cooler running, perfect consistent speeds, and longevity....they nailed it at the turn of this century, low amp draw high torque motors is where it’s at.....the mass majority ( there are exceptions Lou) want to run a train 20-40 SMPH, and they want to do it for hours on end, with out fail....with 16:1 or even 20:1 under command, the amp draws on a fat Pittman are in the dirt....so everything runs cooler, longer, and with out fail...

Pat

Last edited by harmonyards
@harmonyards posted:

......it’s all about low RPM, light amp draws, cooler running, perfect consistent speeds, and longevity....they nailed it at the turn of this century, low amp draw high torque motors is where it’s at.....the mass majority ... want to run a train 20-40 SMPH, and they want to do it for hours on end, with out fail....with 16:1 or even 20:1 under command, the amp draws on a fat Pittman are in the dirt....so everything runs cooler, longer, and with out fail...

Pat

I've begun running my new Lionel Legacy B&A 4-6-6T locomotive (conventional) and according to the Z4000 meters, it's drawing 0.5 amps at 12 volts (engine alone) and 1.0 amp with two MTH 18-inch passenger cars (incandescent bulbs). Both cases at about 30 smph. Whatever type of motor is in there, it seems like very low current to me. Same as my MTH Premier Hudson steamers and Atlas O diesels.

MELGAR

Last edited by MELGAR

I have never noticed any temperature rise when running my modern O gauge locomotives. Who needs to run for eight hours continuously? And I doubt there would be any temperature effect even then. In particular, I have two MTH Premier PRR G-5s locos (PS-1 and PS-2) that have been running trouble-free for more than twenty years. I don't think that design could be considered inadequate. As for the 4-6-6T - we shall see.

MELGAR

Last edited by MELGAR
@MELGAR posted:

I have never noticed any temperature rise when running my modern O gauge locomotives. Who needs to run for eight hours continuously? And I doubt there would be any temperature effect even then. In particular, I have two MTH Premier PRR G-5s locos (PS-1 and PS-2) that have been running trouble-free for more than twenty years. I don't think that design could be considered inadequate. As for the 4-6-6T - we shall see.

MELGAR

@MELGAR,...Who needs to run for eight hours continuously?

I do...I didn’t get into this hobby to admire them....my junk goes to work!..😛😛😛....but that’s just me MELGAR, for most of you guys, they’ll be fine forever....and yes, I agree with you 100%...that little tank engine will be happy pulling 2-3 cars for a couple hour spurts for eternity.......but don’t get me wrong, if I get one and it don’t do what I want it to do, I’ll gut it like a fish and start over....🤪

Pat

I think the potential knock on the 4-6-6T is the gearbox design, it appears to be the old K-Line design that has been very troublesome.  It may survive just fine, there's no reason that layout can't be robust, it's just that previous examples of Legacy locomotives with a similar gearbox have been less than stellar.

What issues have you seen?   No issues here with my Motor forward facing Kline berks or mikes. But then again you see a lot more of them than I do.

I have many K-Line scale and a few semi scale steam engines and none have the intermediate gear shaft nor have ever given me a problem and a few have many hours pulling long trains, at least for a Mabuchi 385. My K-Line engines have been far less troublesome than my Legacy engines. Legacy Schmegacy. Who needs 'em.

Pete

@John Rowlen posted:

I have read the thread.  Has anyone had a new Lionel 4-6-6T engine Fail?  Please post if your new engine failed. 

Gee, they've been in consumers hands for what, a week or two?  I sure hope they're not failing already!  Even the K-4 locomotives with the gearbox issue that I spoke of were kind enough to run longer than that before they failed!

@John Rowlen posted:

I have read the thread.  Has anyone had a new Lionel 4-6-6T engine Fail?  Please post if your new engine failed.  

How many passenger cars are too many on O72 curves?

Is the pick=up roller footprint good for Atlas O switches.  Someone has issues with Ross switches.

Sincerely, John Rowlen

The K-Line Hudsons (same motor) are OK with about 5 K-Line 18" passenger cars. Some of the newer cars may be lighter and freer rolling, if so maybe 7 cars.

Pete

Gee, they've been in consumers hands for what, a week or two?  I sure hope they're not failing already!  Even the K-4 locomotives with the gearbox issue that I spoke of were kind enough to run longer than that before they failed!

Given Mr. Rowlen's history of lemons that he has posted about on this forum, I think that it is a valid, but maybe premature, question.

about my previous post on not going through my long Ross switches that have all the rails wired via a relay. I found one of the pickup shoes was loose. I tightened it up and now running fine on everything even the shorter Ross switches with no relay. also loco runs on my layout nicely with an 8 car passenger train with very little draw from the motor (most is from the lights in the cars).  nice loco now to find some coaches I can paint in the old CN scheme to go with it. 

I think the potential knock on the 4-6-6T is the gearbox design, it appears to be the old K-Line design that has been very troublesome.  It may survive just fine, there's no reason that layout can't be robust, it's just that previous examples of Legacy locomotives with a similar gearbox have been less than stellar.

I don't have the the 4-6-6T (its not Santa Fe  ), but I do have the K-Line Santa Fe 2-8-4 T1b Berkshire locomotive #4198 and the Lionel Legacy T1b Berkshire locomotive #4199. Lionel obtained the molds from K-Line for the T1b model. 

The K-Line version has a RS385PH motor facing forwards in the smokebox and there is a worm pressed onto the motor shaft. The worm engages directly to a large worm wheel which is pressed on a axel with drive wheels pressed onto each end of the axel. Thus, the K-Line has a single worm/worm wheel drive of the locomotive. 

The Lionel has a large Cannon motor (roughly RS540 size) in the firebox. The motor is connected to the drive shaft with a universal connection. The drive shaft has a worm which engages a worm wheel which is pressed onto an axel which rests in two oilite sintered bronze bushings.  The rest is pretty much as photos show above. It appears the Lionel goes through an extra gear reduction vs. the K-Line. From what I have read, Lionel received a lot of praise since the Lionel drive mechanism is much superior to that of the K-Line. Lionel had to do extensive changes to the chassis to do what they did with the drive mechanism. 

From what I can tell from the photos, it would appear that the Lionel version kept the RS385 sized motor for the 4-6-6T (however, not all motors are created equally and Lionel may very well be using a higher quality motor than what K-Line used) and put in extra gear reduction. The extra gear reduction would take the work load off of the motor allowing for smoother operation. 

Thus, it would appear that the Lionel mechanism is not the same as the K-Line mechanism even though the both use a RS385 size motor mounted in the smokebox. 

@harmonyards posted:

When it comes to a RS385, ....I don’t think there’s a higher quality version....they’re all poo....bottom feeders....ain’t worth the crappy can they’re pressed into......

Pat

I would agree when it comes to Mabuchi. 

However, I did not say RS385, I said RS385 size.....

Here are the dimensions for the RS385: Motor Dimension: 1.14 '' dia. x 1.7'' length (28.9 mm dia. x 43.2 mm length)

so if you go here

https://www.haydonkerkpittman....hed-dc-motors/dc030b

you will find DC30B Brushed Motor

Which is approximately the size of a RS385 from Mabuchi, but would be of higher quality. So it is possible to have a RS385 sized motor that is higher quality. But such a motor is not from Mabuchi. The RS designation is just a Mabuchi thing. 

 

 

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@WBC posted:

I would agree when it comes to Mabuchi. 

However, I did not say RS385, I said RS385 size.....

Here are the dimensions for the RS385: Motor Dimension: 1.14 '' dia. x 1.7'' length (28.9 mm dia. x 43.2 mm length)

so if you go here

https://www.haydonkerkpittman....hed-dc-motors/dc030b

you will find DC30B Brushed Motor

Which is approximately the size of a RS385 from Mabuchi, but would be of higher quality. So it is possible to have a RS385 sized motor that is higher quality. But such a motor is not from Mabuchi. The RS designation is just a Mabuchi thing. 

 

 

Oh baby, you don’t need school me on Pittmans....I’m all about some Pittmans....unfortunately, the current owners of Pittman saw it fit to price themselves right out of this hobby ( and many others ) we used to be able to call Mr. Charlie himself and order our Pittmans right over the phone...ain’t happening no more....Lionel & MTH both quit offering Pittmans right about the same time....you’ll have a better chance of getting a snow cone in the land under the dirt before you see a Pittman in a new Lionel product....it’s all about low bid vendors, and Hayden/AMETEK ain’t it...

Pat

Gee, they've been in consumers hands for what, a week or two?  I sure hope they're not failing already!  Even the K-4 locomotives with the gearbox issue that I spoke of were kind enough to run longer than that before they failed!

Well, actually my Legacy k4 had the intermediate shaft walking out of the side of the chassis after lap around my layout right out of the box. I sent it to Lionel for warranty repair, and a few years later started noticing the excessive wear on the shaft bushing.

Its a shame. I really liked that loco. 

@RickO posted:

Well, actually my Legacy k4 had the intermediate shaft walking out of the side of the chassis after lap around my layout right out of the box. I sent it to Lionel for warranty repair, and a few years later started noticing the excessive wear on the shaft bushing.

Its a shame. I really liked that loco. 

Did you get rid of it Rick?....I’d like to fix one of those K4’s ...with a MTH chassis!..😁....that’d be a cool project!...

Pat

@RickO posted:

Yep.It will be interesting to see if these failures occur in the larger locos with this setup. I.E the mohawks, M1a, etc

I would guess if the intermediate shaft is walking out of the gear box or the gear is wearing, its because the gear is not a tight fit on the shaft which could happen if the gear was bored oversize or the knurling was missing or not deep enough.

Knowing this, a fix could be done at first sight this was starting to happen.

Pete

 

@Norton posted:

I would guess if the intermediate shaft is walking out of the gear box or the gear is wearing, its because the gear is not a tight fit on the shaft which could happen if the gear was bored oversize or the knurling was missing or not deep enough.

Knowing this, a fix could be done at first sight this was starting to happen.

Pete

 

Ahh...and if the gear slips off the knurl, it’s going to get cockeyed and wear out twice as fast....

Pat

@harmonyards posted:

I think John had mentioned he had to fix a couple of those K4’s and the only fix was a complete chassis swap...no?..

Pat

That's the fix I was able to do.  I actually got one to run for about six months with some shims to keep the gear from shifting, but eventually it ate itself and that was that.  I don't know how many more of the K-4 chassis that Lionel will have waiting in the wings, I've used three of them in the last couple of years.

I would guess all were made out of spec so a replacement won’t be a permanent fix. You have take it apart before it got too damaged and re knurl the shaft. Fairly major job as wheels would have to come off. I don’t see how you could get super glue in there unless you could be positive there was no trace of lubrication between the gear and the shaft.

Pete

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