2-8-0 Spectrum Free Rolling Issues

[tl7734]

I have a 2-8-0 spectrum that has a couple of issues that need improvements.

Number 1.

The chassis assembly does not provide "free rolling" - defined as being able to have the wheels rotate as it is pushed on track separated from the motor-weight assembly.    If I apply downward pressuring and move forward/reverse the wheel can rotate.

Removing the the factory wheel wiper assembly and using just the flat piece to secure the drivers in place the wheels become "free rolling".   

The sprung drivers (2, 4) are not impacting this issue - the bottom plate eliminates much of the "spring" in those drivers anyway - to the point of making the idea of sprung drivers nearly useless.   It presses the axle back into the frame. I measurement 0.5mm of movement in the factory design. 

It appears that the wheel wiper assembly provides significant friction to the drivers to prevent free rolling which increases the force needed by the motor to turn them,  resulting in poor, slow speed, performance.

The wheel wiper assembly itself is somewhat innovative compared to what we had with brass imported models in the 1960's - 1980's.

However,  the conflicts with the rotation for "free rolling" is a huge disadvantage.

There are 8 contact wipers - while this is great for increased pickup,  using capacitors this amount is not really needed anymore.

Here are my questions -

Is the added friction and loss of "free rolling" ability a know issue to Bachmann designers in Chi-na ?   Since there are using CAD to design this they should know who to test and measure friction levels in eval simulations and prototype a new wiper design that results in 50%-80% reduction which might be enough to enable free rolling - and ultimately,  excellent slower speed performance.
Plus,  better overall wear and longer drive mechanism life.

I would also like to know if anyone has experimented with eliminating some of the wipers and did this enable free rolling?

Looking that the base plate of the wiper assembly,  there are locations that are recessed for an axle - however, this was not done on all axles - a design oversight?      The front axle has an opening to all easy lubrication - however other axles do not have this ability - another design.   A design flaw either way because once the wiper cover is attached there is not access to the openings anyway.  Again, it shows a design gaps.  Perhaps two people designing different parts and they can't speak to one another.

I don't know if the simulated brake levers play a huge part is preventing the free rolling ability.  The sound I get from the "factory" assembly is a "scrapping" sound which appears to be the metal-to-metal contact - wipers to wheel surface.

One thing that could improve the "scrapping" sound would be if the wiper blades edges had filets on the edge - since the back wheel surface is very rough (see under magnification).

Curious to hear is others have "tweaked" their models in order to get better performance.

[rogertra]

I don't get this.

Model steam locos or any powered model locomotives do not 'freewheel' by design.

They only freewheel if you disconnect the motor gears or remove the motor, otherwise, unless something is broken,  they do not freewheel.


Cheers


Roger T.

[Len]

I don't get this.

Model steam locos or any powered model locomotives do not 'freewheel' by design.

They only freewheel if you disconnect the motor gears or remove the motor, otherwise, unless something is broken,  they do not freewheel.

Cheers
Roger T.

The OP said up front the motor and weight assembly had been seperated from the wheels:

"The chassis assembly does not provide "free rolling" - defined as being able to have the wheels rotate as it is pushed on track separated from the motor-weight assembly."

Len

[rogertra]

I don't get this.

Model steam locos or any powered model locomotives do not 'freewheel' by design.

They only freewheel if you disconnect the motor gears or remove the motor, otherwise, unless something is broken,  they do not freewheel.

Cheers
Roger T.

The OP said up front the motor and weight assembly had been seperated from the wheels:

"The chassis assembly does not provide "free rolling" - defined as being able to have the wheels rotate as it is pushed on track separated from the motor-weight assembly."

Len

I'm still at a loss.   I have four old steam locos that I use in my dead line.  After removing the motor, they all freewheeled no problem.  Of course, I've since removed other parts of the motion, like the railroads did, to make hauling 'dead in tow' much easier.

Cheers


Roger T.

[tlong]

Roger, you will have to get one of the spectrum versions of this model to see first hand the exact problem.  This is not like the older versions.  You can find them on ebay cheap sometimes.  I took part a new in box model today to test and the same issue.

I think the wipers are causing the noise and friction.    The latest brass models I have from Boo-Rim have electrical pickup as part of the axle bearing design.  That's the best I've seen so far,  but very expensive.  The same could be done in plastic models I think.

[Bucksco]

Just out of curiosity - are you talking about an HO or a Large Scale model?

[rogertra]

Roger, you will have to get one of the spectrum versions of this model to see first hand the exact problem.  This is not like the older versions.  You can find them on ebay cheap sometimes.  I took part a new in box model today to test and the same issue.

I think the wipers are causing the noise and friction.    The latest brass models I have from Boo-Rim have electrical pickup as part of the axle bearing design.  That's the best I've seen so far,  but very expensive.  The same could be done in plastic models I think.

Yes, Spectrum HO scale engines pick up power though wipers on the backs of the wheels.   Yes, Spectrum and other plastic bodied locos could pick up through the axles but as far as I know, few to none do.

I have around six or seven of the Spectrum HO scale 2-8-0s.  The first one or two were purchased within a year or so of the Spectrum range bring introduced and the last one purchased was the one that came with a sound unit, that was about four years ago.  Other than the pickup wipers sometimes being slightly out of alignment, due to pack issues or perhaps vibration during shipping and producing a clicking sound, I have had none with a binding issues you are discussing.

How did you come upon this issue?  Was the loco's mechanism binding when you first purchased it?   Having a loco binding with the motor removed is unheard of as there's nothing left to bind unless someone has mishandled the loco and perhaps squeezed the motion together so that it is locked up.  Then it's just a case of carefully bending ot back into the correct alignment.  A fairly delicate but not difficult task.

Cheers


Roger T.

[Ken G Price]

Six days and no reply from OP!

[rogertra]

Six days and no reply from OP!

Not an infrequent happening.

Cheers


Roger T.