Bachmann 2-8-4 Berkshire/Kanawha in stock at M.B. Klein

[victor miranda]

guys, from all I can tell about this b-mann berk
it comes with three potential problems.

so you can have none all the way up past the standard three.

quartering issues, wiring/pick-up issues, and some kind of gear issue.

because Max is a good locomotive tinkerer, someone sent him a problem loco.
please do not equate the one he has as typical...
even if it is... because I am hearing that some have great locos
without issues.


lets back away from that for a bit...
you may want to consider this loco in comparison the the  Kato FEF.
If you think that Kato has built a proper steam loco,

there is so much to get right for a loco to avoid quartering issues.

Also, there is keeping wires from being harmed in the run from tender to engine
should you need to run wires.

round and concentric gears, handling worm thrust.

Kato get this right with noteable exceptions.

so, consider that b-mann has made a big loco with a coreless motor.
what that means is that this loco can go sloooooooow.
and what you see as problems are a direct result.

my berk stalls/ stutters more from electrical pick-up than from quartering.
and mine does have a small quartering or gear  problem.

again bach mann has made a 'test before you buy' loco.

[victor miranda]

sizemore:  Good info.
I am hoping the quartering isn't that bad when I get to working on that aspect.

I've had this one apart a little.  First off, there's an issue where the siderods will jam if the front driver is allowed
to move all the way side to side.  TopHobbyTrains even has a youtube video on this and they even show a "fix" for it wherein they bend the side rod between #1 and #2, on one side only, which effectively shortens the rod distance between those two drivers.  I put a shim down in the axle cavity so keep the front axle from moving too much side-to-side and that also fixed it.  It can cause a hard jam in reverse.  I'm sure it doesn't happen on every engine.

That had a pleasant side effect.  Although I'm sure I gave up some tigher-radius running (who cares?), by limiting driver #1's lateral play, the engine stays more centered on the track, and it could just barely get my 20-car test train up the hill (with some slip).  It couldn't do that before.

Still runs flippin' lousy though.

While I had the cover plate off, I ran it at low speed and watched it run.  The main idler between 2-3 is nasty.   It just wiggles and wobbles all over the place. 
It spins on a pin that is cast into the right-hand frame half.  But the metal nub on the left-hand frame half that is supposed to limit the gear's side-to-side play is a misshapen blob, and the gear itself wobbles on its pin way to much.
Sigh.  The parts, the tolerances, the fit...  It just ain't Kato. 
I am going to try making a shim of some sort to slide down in next to that gear so that it will stay put and stay vertical without so much wobbling.  That may help everything run more uniformly.  Then again, I may find that the mechanism can't run at all without all that slop in it.  We'll see.

It definitely has a bad bind at 2 spots in every rotation in forward, and 1 spot in reverse.
And remember, the decoder is not in this engine anymore.  These symptoms are all from the drivertrain itself.

I quoted because this post has a LOT of good points in it.

I love the "it just ain't Kato."

'k front crank jams I'll watch for that.
and idler gear wobbles.  I expect this will be a forever problem.
there is a good reason to not build it this way... it jams unless the pivot is a good bearing.
and none of them are and the gear can lift a jammed driver....

I suspect you have electrical pick-up problems BTW...

[peteski]

so, consider that b-mann has made a big loco with a coreless motor.
what that means is that this loco can go sloooooooow.
and what you see as problems are a direct result.

Is that confirmed?  I thought someone else in this thread said that it was a standard can motor.

[Chris333]

because I am hearing that some have great locos
without issues.

Some people are just happy it moves when placed on the rails. Seriously I bet if all the people on this forum were in my basement watching as I complained about the gyrating drivers, half of them wouldn't see what I was talking about. And this is after I got it to "run".

I remember being one of the first people to sign up for Bachmann's On30 gear problem. Many people bought brand new On30 locomotives that didn't run right out of the box due to cracked gears. I had 3 locomotives that had cracked gears. 2-3 years later they sent me a little baggie with replacement parts. That is a long time to have a ~$150 loco sitting around and is probably why I don't do more with On30. Another one of thire On30 locomotives has egg shaped flanges. The wheels are true, but as you watch at low speeds you see the flange bouncing up and down...

This just looks like the N scale version of their regular problems.

[victor miranda]

Is that confirmed?  I thought someone else in this thread said that it was a standard can motor.

what would you consider confirmed?

[peteski]

what would you consider confirmed?

I guess the absolute way would be to take it apart.    But having someone knowledgeable in motors (like you or several others here) examine it and determine whether it is coreless or not is good enough. 

I asked because earlier in the thread there was a discussion as to whether it was a coreless motor or just a regular can motor and I don't recall anybody giving an absolute answer.  Maybe I just missed it.

[victor miranda]

I have seen a picture I did not take.
the motor is a cylinder about 20mm long  x 6mm diameter
dimensions proportioned from the photo...

those proportions are hard to make anything except coreless

the loco acts like it is coreless as well.

mine with the sound going uses
70-80 ma and at about 7-7.5volts
towing about 15 cars around 25-30 smph.

( my experience is that sound decoders use 1000 mW at all times
so I think the motor is generating power...)

it will be a while until I get in there.

you can be reasonable sure the motor is coreless.

victor

[mmagliaro]

I support Victor's assertion from observation, and also:

Mine is running on DC only, so I can measure the absolute motor current. 
At 5 volts, no cars on it, in forward, on level track, it uses only 25 mA.
In reverse, I have no backup light wired in yet, and it draws about 20mA., which makes sense (no LED).

I don't know of any conventional motor I have ever seen that could possibly be drawing so
little current and moving an engine down the track. 

[peteski]

Does the rear cover look similar to this (Plastic plate with wires coming out)?  That is also a fairly good indication of a coreless motor.

[victor miranda]

Hi peteski,

the motor has a shaft on the ... back...
and there is a flywheel off that.

this is part of the reason no one wants to open it.

coreless motors are the least expensive option at that size.

you really think that b-mann is going to build a very long 5mm dimeter
3 pole motor to go in there?

'cause of those two ideas,  I find no reason to doubt.

.... most people seem to think coreless is the best possible option.

victor

[mmagliaro]

Hi peteski,

the motor has a shaft on the ... back...
and there is a flywheel off that.

this is part of the reason no one wants to open it.

coreless motors are the least expensive option at that size.

you really think that b-mann is going to build a very long 5mm dimeter
3 pole motor to go in there?

'cause of those two ideas,  I find no reason to doubt.

.... most people seem to think coreless is the best possible option.

victor

Rats.... GRAMMAR ERRORS!
---------------

A 6mm Maxon or Faulhaber will cost well over $100.
And getting a backshaft on it so you can mount a flywheel jacks the price up even more.
Call me skeptical, but I don't see how a good coreless motor in that size could be made at a price point
that would make it practical to use it in this engine.   So this motor must be something "special" and I'm dubious
of its quality because I've seen lots of cheaply made coreless motors, especially in these tiny sizes.

I will respectfully remove my name from the list of "most people" 
(who think a coreless is the best choice for this engine)

[victor miranda]

this thread reply #144...

i said :
"and until b-mann can get the rest of their quality control in hand
they are not going to see much benefit from using a coreless motor."

if Kato's execution with a coreless is what is possible...
then a coreless has some merit.

I am sticking to that quote. coreless motors require
truly good mechanisms.

the problem is how b-mann installed that motor/worm.
it is on the motor shaft. thrust from the worm will take up a lot of power
and move the motor and attempt to flex the shaft and motor-mounts.
traditional coreless motors do not take thrust well.

in design, the worm should have its own bearings.
the growls may well be from the worm/motor getting jacked around under load.

ooof  no easy solution there...

victor

[mmagliaro]

Well, to wrap this up, at least for me.
I was loaned this engine to experiment with, to see how it works, and to make some improvements to
it if possible, without resorting to tearing it to pieces and completely rebuilding it.

I have done that, and now I'm done with this thing.

I corrected the quartering on driver 4 as best I could.  It helped.  But it still runs lousy.
The rods have sloppy egg-shaped holes in them which is really bad for driving a driver around on rods.
Look at how precisely the holes are drilled in the rods on a Kato Mikado or C55 and then look
at the rod holes on this thing.

Short list:
1. quarter driver #4
2. U thingy between bearings on driver 1 so it can't slide back and forth enough to induce a full jam
3. filed bearing pocket on #4 so it doesn't carry all the weight off of #3 (where the traction tire is!), which
did really help with driver slip.  At least it can now pull 20 cars up my 1.7% hill... BUT
.... 3a: You have to juice the throttle up hills or the motor... will...come...to a... complete... stop..

4. Made a U-shaped shim with a phosphor bronze sheet on one side to slip down next to the wobbly idler gear
inside the frame.  It does really help that gear run truer, and I *think* that stopped the engine from
 having unexplained full jams every once in a while that were not rods or quartering (i.e. all the rods would be free,
nothing stuck, but the geared wheels were locked).  At least that doesn't seem to happen any more.

--------------
What else is still wrong with it.

1. Every wheel on the thing is too narrow in gauge, but it will run okay on the owner's track (it clicks and bumps
occasionally over my code 55 frogs)
2. The motor (as noted in 3a) is grossly underpowered for this engine.   

---------------
There are so many well-understood, well-proven ways to make an x-8-x mechanism.  Why this?
Heck, just copy the Kato Mikado and be done with it. 

[peteski]

There are so many well-understood, well-proven ways to make an x-8-x mechanism.  Why this?
Heck, just copy the Kato Mikado and be done with it.

LOL!  You really think it is that easy?

Even if they copied it, the inferior tolerance and materials Bachamnn would have would make it just as bad as this loco.  That is the difference between Kato and most other manufacturers: Precision design and manufacturing, and superior quality materials.  Kato is not perfect either, but they even with their missteps, they are usually way better than the rest.

[jdcolombo]

Thanks for your list of adjustments, Max.

I've done the quartering.  I've re-gauged the wheels.  Haven't yet tried to shim the #1 driver or do something with the idler gear.  Mine run "OK" enough that I will probably leave them alone, especially since I only use the Berks to run mainline trains (no switching duties for them).

In retrospect, the engines aren't worth anywhere near the $210 each I paid for them.  The sound system is below my acceptable range and the operational characteristics are barely acceptable.   Lesson learned - I'll wait for reviews before ordering another Bachmann loco.

What I don't understand is why the Berk is so inferior to the EM-1 or 2-10-2 or 2-8-0.   Do they make those in different factories?  Different production lines?  The EM-1 is a beauty, fully as capable as any Kato engine or the Athearn Challenger/Big Boy.  It runs like a Swiss watch and will pull like the prototype.  How can a company make something as great as the EM-1 and then follow it with something as inferior as the Berk?  I just don't get it.

Live and learn.   Fortunately, I still have my 10 Walthers/LL Berks to fall back on.

John C.