I've had this older used Bachmann 4-8-4 for a few years and it never ran good from the start so I finally decided to look into fixing it. All the gears are cracked on the spline but the worst one goes through the teeth on one of gears as seen in the pic. The only good gear is the double gear that drives the others. I looked on Bachmanns web site at these (https://estore.bachmanntrains.com/i...ucts_id=5806&zenid=eo8iv5om30jc6ei39ubnea26l6) and it states they're for the Northern but will work on the older gen. 4-8-4's but I don't see a spline on these gears that the wheels would press into. Does anyone have any experience with using these in the older Bachmann 4-8-4?
GOOD LUCK. I'm not sure exactly what issue Bachmann 4-8-4 you've got, but very few of the early issues ran any good for very any long. The gearing was one of the big problems. They would CRACK[like yours did] and the motor drive shaft would frequently become misaligned with the drive gears. it was usually an unsolvable problem. You can put new gearing in the engine, have it run for a couple of days, and have problems again. Usually they ended up sitting in the roundhouse. The early Bachmann 4-8-4's were the Steam Engine that drove more people away, because of POOR RUNNING, from N-Scale STEAM than anything. I have heard, I don't have one, that the later issues ran OK. Maybe somebody else can answer about engine performance.
There were a whole series of Bachmann trains steam and diesel that experienced split gears and axles on those with the split axle set-up. Used to be one could go to Northwest Short Lines for gears but NWSL shut down operations several years ago. The only solution now is to go to Shapeways or similar to see if anyone is making gears.
Actually, the solution is to use thin walled tubing and cut sleeves out of it to go around the axles to hold the cracks together. I did it with my old White Box 4-8-4. Doug
I tried that years ago on several using thin walled brass tube and the results were not worth the effort and time. This is a similar article that I followed the technique is the same. https://www.zealot.com/threads/repa...manns-n-scale-4-8-4-locomotives.108579/page-2 I also ran across an article by a English gentleman who made his own shapeways style replacements on his own printer but danged if I can find again but that may be the answer.
That's pretty much the same procedure I used. To me, it was worth it to see that huge 4-8-4 running smoothly again. As far as replacement gears/axles, there was a discussion recently on one of these forums about it when that guy proposed 3D printing gears and the problem is that, unless some kind of super, crack proof material can be found or they are made of metal, the replacements will crack too. It's just generally a poor design, stuffing the metal axle stubs into plastic. There are always weaker spots in plastic moldings and the weak spots will crack from the forces/tension. You would think they would have redesigned that assembly in short order when field problems began occurring. They finally did with the latest release. Doug
Thanks fellas. I'm almost sure this was the white box version. I like the brass sleeve idea and will keep that in mind should I run across some new gears. To bad they don't make brass replacement gears. I could only imagine how many 4-8-4's could be resurrected from the steel yards LOL. It may end up being weathered and rusted and sitting next to the Allied Rail rebuilders yard but I'm not going to give up so easy on the "hope" lol lol lol that I will eventually find gears for it.
I found this site interesting to. (https://jamestrainparts.com/2019/02/11/bachmann-n-sacle-4-8-4-replacement-gears-part-1/) It shows 2 extra gears on that 4-8-4 which would give it all 8 wheels driven. Mine just had the four in it which means only 4 wheels are driven but that's fine. Just getting it running and using it for a lighter weight switcher would be cool anyway.
A stock Bachmann 4-8-4 should have all drivers geared. Did somebody remove some of the gears in yours? Doug
I aquired it in a box of stuff I bought off of CL about 5 yrs. ago. I test ran it once and it ran like a flat tire and I put it away. I decided to tear it down and take a look and thats what was there. Only the 4 gears and the 1 dual gear that the motor drives. They also used the brass sleeve method on 2 of the gears and 1 of them being the gear that is split through the teeth. One of the gears is hard to see in the pic but it is there. It's toward the front of chassis.
I just thought it would be cool to watch it chug along while listening to "The Zoo" by the Scorpions. lol
Going by the pic of the gears on the Bachmann site that they are sold out of, look like the gear of the ones that are missing from mine and not the ones I need to replace that are cracked. That's just going by the picture though. It looks like they're sold out on the drive wheel assembly which would work to
