Wobbling E-R Shark unit -FIXED!!

[OldEastRR]

This guy shimmies and waddles down the track -- a B unit rear truck of a set but the A unit rolls smoothly. Wheels in guage, no gunk in the gear teeth. Anybody else have this problem and can it be fixed?
OTOH, with a decoder in them these locos aren't much noisier than a KATO unit, even at top speed (65 smph). Which is surprising.

[brokemoto]

The same factory that manufactured B-mann products manufactured these.
Some of these with the white gears, especially the first runs, suffered from the B-mann Cracking Gear Plague.
The later runs, with the black gears do not report these problems.
I have read and heard that you might be able to substitute the Northwest Short Line replacement geared wheelsets that it sold for the B-mann PLUS, which also suffered from the Cracked Gear Plague.  I have yet to read or hear a report on the results of that.  Someone did post here that he could not find the NWSL wheelsets, so he glued the crack and it did work.

The first runs of the three major users, B&O, NYCS and Penn had the later paint schemes:  1959, Cigar Band and single stripe, respectively.  The second runs had the as delivered schemes of the three major users.  The Monongahelas were second run.  I am not sure about the D&Hs.
The change from white to black gears must have been made at some point during the second runs.  I have four of the B&O (two re-numbered):  two have black, two have white gears.  My Penn five stripe pair has white.

[peteski]

I've seen black gears crack too - just not as frequently as the white ones.

[OldEastRR]

And if no gears are cracked?

[peteski]

And if no gears are cracked?

Well then, place the loco upside down (in a loco cradle if you have one), use test leads to apply power, then observe wheels and  see what causes the wobble.  Most likely the whee sets are the culprit.  That's the most common reason for model wobbling while running. Maybe the gear/axle tubes are not molded correctly, or the sheels with half0axles are imperfect.  The fix would likely to find better wheelsets (from another ER-Shark).

[brokemoto]

And if no gears are cracked?

In many, but not all, cases, the crack is in the sleeve that holds the two pieces of the wheelset together.  You have two wheel pieces with just-under-half axles.  They friction fit into a sleeve on the gear piece.  Often, but not always, the sleeve gets a crack that runs horizontally along the sleeve.  When pressure is applied to the gear, it tilts out of alignment and causes wobbling and jumping.

Other possibilities are misaligned or poorly seated gears.  Some of the teeth might have imperfections.  Some might be missing teeth.

The most common culprit that I have seen on these and the B-manns is the cracked sleeve.  Often, it is almost microscopic/hairline crack but I always have been able to see it under a magnifying lamp.

[peteski]

This is what the problem wheelsets look like (both white and black gears).  Black gera only has the tubes cracked, while the white one is split all the way across (including the gear).

[Doug G.]

A very poor design.

Doug

[peteski]

A very poor design.

Doug

Well, pretty much every Kato diesel uses a very  similar design (plastic axle tube with integrated gear, and wheels with half-axles), yet those don't seem to have that problem.  Kato is not perfect (other tubular plastic sleeves do crack, but not the diesel wheelsets.  Atlas (based on Kato design)  also uses similar wheelsets.

While the Bachmann design is not optimal as the thick diameter half axles probably contribute to the problem (Kato uses thin 1mm stainless steel axles), the materials quality, and loose manufacturing tolerances (since those Bachmann half-axles are turned as a single piece with the brass wheels) I believe are the major contributing factors to the frequent stress-related breakage.

[Jbub]

I'm still trying to find a replacement for the gears that split on my Bachmann DD40

[peteski]

I'm still trying to find a replacement for the gears that split on my Bachmann DD40

You might be able to fix those by installing sleeve over the cracked axle tube like I described in https://www.therailwire.net/forum/index.php?topic=49440

[Doug G.]

The way to do it is to have the plastic plug into the metal instead of the other way around. That's the way Sekisui (Kato) did it on the original PAs.

Doug

[OldEastRR]

No split gears. No bent axles. No out of round wheels. no deformed gears. One wheel was not completely seated on the end of the axle. A little pushing with a thin rod and it got fixed. No wobble now. Of note, when we took the truck frames off we saw that some gear shafts were protruding out from the axle housing. the shaft ends should be flush with the outside of the gear case. Tho that wasn't the problem it probably helped things were readjusted to specs.

It appears that (despite the Bachmann heritage) these units were well-designed and crafted. The problem was apparently one truck wasn't assembled right. So yeah, get stuff built cheap in China .. but you gotta put them together right if you want them to work right.

[peteski]

Well, aren't you the cat's meow!  And since the fix was much easier than any solutions given to you here, if you disassembled and examined the trucks even before posting your questions, you could have fixed it - all by yourself.  Good job!

[OldEastRR]

Being catty, Peteski? No worry about the work, a friend has the engine and did all the work. It did involve disassembling the trucks (we couldn't figure out how to get them off the frame), and we rolled the axles by themselves to look for out of round wheels, checked the gears for cracks, bits of something in the teeth or lint, if the gears were seated where they should be on their shafts, pushed the extended axles into place, before he wondered if the wheels were completely seated in the plastic hubs of the wheels. Pushing on the wheels in question solved the puzzle.

There is no exploded diagram of the E-R sharknose included in the box, so that wasn't much help.

Also, I read that these locos were supposed to be loud. Not really. Even quieter w/ decoders to smooth out the current flow. They do have that wonderful ozone smell like the early N locos had -- is that what it smells like when a (real) GG1 goes by?