Gear tower trouble in my AC6?

[ATSF_Ron]

Here's a question for our knowledgeable steam loco repair gurus.  In looking at a closeup of my pics of the AC6 disassembly in another post, I see what might me a crack in the gear tower/worm gear cover of the rear engine set on my AC6.  Maybe it's a crack/deterioration of the material, maybe that's just how they look after 30+ years, or maybe that's just how they fit.  I believe this was a 1986 run.  I don't recall seeing this type of a space at the top of the tower in other brass locos I've had open recently.  I'd rather not open this one back up again, as it's a bit of a pain.  There's still a small amount of noise (but not horrid) coming from the front driver set.  This pic is the rear set and I have ZERO noise coming from that.

I'm closing in on my 30 day return window, so if this will turn into a worse problem some time soon then I'll most likely return it.  Replacing said part is definitely beyond my skill set.  What do you guys think?  Thanks.

Ron

[ATSF_Ron]

I just took another look at Spookshow Mark's site where he has a pic of one of these opened up.  His front gear tower/worm cover looks very much like my rear one.  Maybe that's just how they fit together...

[peteski]

Those gear cases are 2 halves split vertically (held by screws).  I would  not worry too much about what looks like chipped away metal on the top. Since it is blackened like the rest of the gear case, it the factory in that condition.  I'm worried a bit about the gap. The gear case halves should fit pretty closely together.   But  if the worm bearings do not have too much side play in the gear case, then it is probably ok.  It would be helpful to evaluate the situation by opening the gear case to see if there is something there (like white-metal pest condition) that is causing the halves to separate.

While not the same as the one in your model, it uses similar design.



If your gear case has 2 screws on the bottom retaining a cover which holds the axle in place, once you remove that, the gear case can be removed from the loco and examined more closely.

[ATSF_Ron]

Thanks for that photo, Peteski.  Very helpful!  I may drop that rear driver set out later this week.  I just got it put back together yesterday, so I need to give my nerves a break before I try again, lol!  I still have about a week before I need to make a final decision.  I didn't notice any free play while I was handling it and lubing things up.  Then again, I wasn't really looking for any.  Best to be safe and check it again.

[Mike C]

   @peteski   Your pic shows a more serious problem with these locos ( a lot of older brass has this problem ). The brass on brass mesh of the gears . Looks like that worm is about done . I don't know if anyone makes a plastic idler gear for that gearbox @ATSF_Ron , but I would limit it's run-time .  I've done a few HOn3 models where I have had to replace the idler gear . Its not hard to do and maybe someone would print a gear that would work .    Mike

[Chris333]

I'd try to spin the input shaft with something round like a pin vice. You should be able to feel any binding.

[peteski]

   @peteski   Your pic shows a more serious problem with these locos ( a lot of older brass has this problem ). The brass on brass mesh of the gears . Looks like that worm is about done . I don't know if anyone makes a plastic idler gear for that gearbox @ATSF_Ron , but I would limit it's run-time .  I've done a few HOn3 models where I have had to replace the idler gear . Its not hard to do and maybe someone would print a gear that would work .    Mike

Thanks Mike. I realize that's a problem. That is not Ron's loco's gearbox.  Seven years years ago I did some work on VonRyan's brass loco, and that was one of my findings.  Here is the entire post: https://www.therailwire.net/forum/index.php?topic=36396.0

[ATSF_Ron]

Chris333, I was actually able to spin the worm drive with my thumb and forefinger while I had the driver side out. I could not feel any binding. It felt very smooth to me. I’ll probably take it apart again tomorrow and see what gives.

[Chris333]

Whatever that cracking is, it could just be how it was cast. If you poke the worm from the side with a knife and there is not a lot of side to side play I'd say it is something else. You can see the two bushings in Pete's photo. if they are tight then the gearbox is holding them

It is very rare to get a brass locomotive that runs good.

[Mike C]

  @peteski  Yes I realize that was just an example of the gearbox . I just wanted to warn Ron that it may be a problem down the road if his gearbox is similar .     Mike

[Mike Madonna]

Ron,

I just checked the same gear box tower on my AC-5. There is a small "slit/split/opening" in the tower. It does NOT go from one end to the other. The top of that tower measures 9 mm. The split I have is in the center and measures 7 mm and may be .5 mm wide. However, the ends DO make contact with each other. When "cleaning up" this loco's drive train, I did NOT disassemble the gear tower. I did remove the bottom of the case to visually inspect for shavings, lube (or lack thereof), etc. When I reassembled, added a  little Labelle 106 on the gear. Then, using the drive shaft "yoke", manually turned and rotated the drivers to spread the 106 and check for smoothness. I feel as long as that worm is supported properly, the mechanism should work with out issue.

[ATSF_Ron]

Thanks for checking on that, Mike.  I appreciate the info.  My guess is mine is pretty much like what you describe.  However, I think I will still open it up again just to be sure both ends are touching and there is no "slop" in the worm/gear tower area.  When I first got the loco a couple weeks back, I did take off the bottom gear covers you mentioned and did some lube that way.  This was before I decided to brave the innards of the drive, so to speak.  I didn't see any sign of shavings at that time or when I had the drive out the other day.  Fingers crossed...I'll probably open it up again tomorrow and report back after my sanity has returned.

[carlso]

OK, I have a comment and a question.

1st. - In Ron's image above I see that the tower appears to be cracked all along it's length. Yes ? ?
         Also in looking at the image I see what appears to be a crack and some DIY soldering on an
         item. Don't have a clue what it is biut it appears to wrap around the drive shat next to a
         u-joint. Good or bad ? ? Could be my eyes.

2nd. - I have 3 KEY brass locos that run extremely well. A Challenger, a 2-8-0,  and a 2-8-2. The
          challenger is DCC the other 2 are not.

[ATSF_Ron]

Hi Carl.  Yes, there appears to be some cracking, but...it MAY be just the material used.  I'll know more after I reopen the drive in a little bit.  Mike mentioned that his AC5 has a similar "split" in the gear tower, and Spookshow Mark has a photo of one opened up with a similar split on the front gear tower.  As far as the DIY soldering job, it looks to be a sloppy leftover from the factory or maybe the previous owner?  It appears to be a piece that surrounds and holds the drive as it comes into the gear tower.

[robert3985]

Whatever that cracking is, it could just be how it was cast. If you poke the worm from the side with a knife and there is not a lot of side to side play I'd say it is something else. You can see the two bushings in Pete's photo. if they are tight then the gearbox is holding them

It is very rare to get a brass locomotive that runs good.

I've had over the years several dozen brass steam engines and they ALL ran/run really well.  Some of them took a bit of fiddling to get running smoothly or so they didn't short, or adjustment to connecting rods and/or valve gear, but the very best running steam engines I've ever had were brass engines...Late-run Samhongsa/Key FEF's, early Nakamura/Key Challengers, Key Big Boys, and MoreLik GS-2's, all of my Samhongsa/Key Light USRA MacArthurs and all of my Oriental & Key 2-8-0's...right out of the box.

I've also had over the years several dozen plastic steam engines and the very worst running steam engines I've ever had were plastic, such as early Kato GS-4's, Con-Cor Big Boys and Challengers and that Atlas POS articulated whatever-it-was, which still lies disassembled in its box since it never would run.

Some of the best-running steam engines I've ever had were plastic...particularly late-run Kato GS-4's, all of my Kato FEF-3's, BLI Light Mikes, all of my Athearn Big Boys and Challengers, all of my BLI Big Boys and all of my Bachmann 2-8-0's.

Some of my brass engines were bought used, some new.  The used ones usually required tuning up and/or repair, while the new ones always required some break-in time.

In my experience, and maybe I'm just lucky, I don't perceive any difference between plastic & brass steam engines as far as running well is concerned, other than it's generally easier to fix brass steamers than plastic ones since the mechanisms on the brass models are much more basic and amenable to tweaking.

Cheerio!
Bob Gilmore