After 7 years of faithful service, the gear failed...

[Kevin Strong]

TRR #3, the railroad's venerable Bachmann outside-frame 2-8-0, broke its main gear while pulling a short freight into Shade Gap. EBT #3 was dispatched to pull the train to Blacklog, then pulled #3 to the EBT's Rockhill Furnace shops for repair.

The TRR management considered the options available:
1) Buy the replacement plastic gear from Bachmann ($3 plus shipping) (The individual gears are not the main axle drive gear, but the gears within the gearbox. - K)
2) Buy the replacement wheel, axle and gear from Bachmann ($20 plus shipping)
3) Buy a replacement brass gear from NWSL ($12.95 plus shipping)
4) Buy a BBT motor/drive (Price unknown; well worth it, but not in the budget)

The plastic gear was kicked around, as this one lasted 7 years, and one could buy a handful of replacements for the cost of the NWSL gear. The replacement wheel/axle assembly was deemed unnecessary, as switching out a gear is a fairly mundane task for the shop crews. In the end, they opted for the brass gear from NWSL. The plastic replacement gears may last another 7 years, maybe longer, but maybe shorter, too. The brass gear isn't going to break. Due consideration was placed relative to wear and tear on the other gears in the drive, but failures of those gears have thus far proven rare.

NWSL part # 2226-6

Once the TRR receives the replacement, crews will give #3 a proper overhaul, making sure she's good and ready to return to the road in full form.

Later,

K

[grayfitz]

Hi Kevin, I hope my 2/8/0 lasts as long,I understand the references to Bachmann& Barrys, But what is NWSL ,We here in AUSTRALIA we dont have the availability of parts as in USA, GRAYFITZ.

[Craig]

Hi Kevin, I hope my 2/8/0 lasts as long,I understand the references to Bachmann& Barrys, But what is NWSL ,We here in AUSTRALIA we dont have the availability of parts as in USA, GRAYFITZ.

NorthWest Short Line
http://www.nwsl.com/

[Kevin Strong]

Note that Nortwest ShortLine recently got bought out, and the new web site is still something of a work in progress. Finding what you want--even with a part number--can be a bit problematic.

This is NWSL's on-line shopping portal. Enter the part number (2226-6) in the search window and proceed from there.
http://shop.osorail.com/

Later,

K

[Barry BBT]

Kevin,

I have read about the NWSL replacement gear "in Brass".

I voiced my concern to some of my cohorts and was advised that the NWSL gear was not brass, but Delrin.....a far superior choice.

The rule is that the driving gear must be harder than the driven gear.  I follow this axiom and it works for me.

Info: my repair for the 2-8-0 is a complete new gear box and Pittman motor, plus my warranty.  The Price is $200.00

and the customer can install it.

Barry - BBT

[Kevin Strong]

According to the e-mail, it shipped out yesterday. I'll let you know what arrives when it gets here. Brass certainly is less prone to breakage, but if the Delrin lasts, I won't argue there, either.

Thanks also for posting the info about your replacement drive. I wish it were in the budget.

Later,

K

[Barry BBT]

Kevin,

I guess I should have made the point why the brass final gear is not a good choice, and that is that it will cause the driving gear (plastic) to wear faster than it would normally.  So you are right the brass would last longer, but would put the driving plastic gear in jeopardy.

Barry - BBT

[StanAmes]

Barry

I am confused.

On my railroad I use several geared drive boxes with a large reduction and a lot of power that I purchase from Granger.  I use one to turn my turntable. The final gear is metal and the gear on the motor shaft is metal.  All the other reduction gears are some form of plastic.  These gear boxes are in wide spread commercial use (outside model railroading).

By far the greatest force is between the metal gear and the axle it turns.

What confuses me is why would a commercial company who is in the business of making such gear boxes make this selection if it is an inferior design.

I have no expertise in this area so just trying to enhance my knowledge base.

Stan Ames

[Kevin Strong]

I'm usually of the "lubricate the daylights out of it" school of thought when it comes to gears, so given that and how little our locomotives are actually run in the grand scheme of things, I'm not sure wear (especially on spur gears as these) is quite as worrisome as it may appear in theory. Given that the stock gear broke with all the teeth looking brand new, I think I'd have to run them a lot more than I do to get any kind of measurable wear.

Speaking of gears, though, my 4-4-0's main gear decided it was going to start spinning on the axle today. It's not broken, it just started slipping on the axle. It's not turning out to be a banner year for gears on the TRR this year. I've got a 2-6-0 gearbox that gets hot to the touch after around 30 minutes of operation. The gears begin to make noise and the loco slows to a crawl on grades. My first 2-6-0 gearbox did the same thing until I lubed the daylights out of it with lithium grease. (I can't find my can of lithium grease at the moment to do this one.)

Later,

K

[Barry BBT]

Kevin,

You should know that the axle gear in the Connie, Spectrum 4-4-0 and Spectrum 2-6-0 are identical.  Which means they will have nearly the same fail rate and can be repaired by you.  The repair has a better chance of survival that the stock gear.
I have posted the repair procedure before, if you would like it again, just ask.

Barry - BBT

[Barry BBT]

Stanley,

Confused?  Why would a company not follow the engineering rules?  probably because it is cheaper.  Swap out a metal gear in a low risk section of a drive train and it can work.

I follow the rules because I have a different environment, more constant running.  Units with thousands of hours and no gear failures. 

Barry - BBT

[Kevin Strong]

You should know that the axle gear in the Connie, Spectrum 4-4-0 and Spectrum 2-6-0 are identical.

Interesting (good to know, too.) I wonder why they seem to be more stable on the 2-6-0/4-4-0 than the 2-8-0. At least, you rarely hear of people complaining of cracked gears on the smaller two locos. Could it be that there's just enough of a difference in the axle diameter? (I'm in "thinking out loud" mode, not necessarily looking for answers--unless anyone has them.)

Later,

K

[bob kaplan]

Interesting and useful info here....thanks. 
i have a couple of Connies and it seems as if there will be a point where gears will have to replaced on them.   i have instructions for disassembling the boiler from the chassis...but might someone provide info that will help me remove the drive wheel/gear from the chassis....anything would be appreciated.  i've done a couple of searches (perhaps wrong choice of words???) but i have found nothing useful. i have done very little work on large scale engines...i used to assemble Bower, Model Die Casting, and Mantua HO engine kits long time ago....is this replacement probably something i could do...or would i be better off sending them to Bachmann?
   Thanks for the help!!

[Loco Bill]

Maybe we can ask Kevin to photograph his repairs to his connie and post it as a how to item!!

Kevin, if no one asks consider that I am asking,  it would be a fantastic contribution to the forum!!!!

[Barry BBT]

Dave Goodson has written the dis assembly instructions and I use them (with his permission) in my instruction set for the BBT Motor and gearbox install.  Which includes the 'how-to' for removing the third axle, journal boxes and bearings.  The instructions include photos to help.

Mr. Kaplan send me an email with your address and I will send what you need.

[email protected]

623-936-6088

Barry - BBT