Kato GS-4 drive gear slippage help needed

[up1950s]

I got the new GS-4 today from Trainland , and rods and some other parts from Kato came today as well .

[peteski]

The reason all the drive rods were separate was not cosmetic!  Because this loco (just like the real counterpart) actually has some of the drivers either sprung to in eleongated axle holes, those drivers move up and down.  This is done for maximum electric pickup and pulling power.   The drivers also have  lots of side to side play (to be able to traverse sharp curves). I suspect that if the siderod is now a single stiff piece, this pretty much makes that special suspension non-functional (or it will start binding even more).

  Sometimes I just don't get what people do or how they "fix" things!  Bring on the duct tape! 

[victor miranda]

oh peteski...

I may have to take your lighter also
for manhandling some ones' feelings.

as repairs go, often there are undesireable results.
he did what he felt was a good way to repair.

the sprung driver will be less effective
but if that takes the load off the broken axle
how is that not a good repair?

victor

[havingfuntoo]

Hey UP1950's .......... I am proud of you boy ......... I like the way you have gone about learning how to solve this problem of yours, even if the end solution is a trip to the LHS ......... your willingness to not give up is admirable. Any criticism  is just not justified in my opinion (how can you improve if you don't have a go). I have enjoyed the reporting on the saga of your endeavors  and look forward to more of your tales of adventures in train land ...... what do they say ....... what does not kill us only makes us stronger. Some of the offered solutions have kept me enthralled.  Thanks for the tale of the slipping wheel.   

[peteski]

oh peteski...

I may have to take your lighter also
for manhandling some ones' feelings.

as repairs go, often there are undesireable results.
he did what he felt was a good way to repair.

the sprung driver will be less effective
but if that takes the load off the broken axle
how is that not a good repair?

victor

Victor, after all the years on the Atlas forum you should know my personality. I have no problem with speaking my mind.    Especially when presenting facts (like describing the GS-4's running gear design).

The sprung suspension in the GS-4 is *VITALLY* important for maximizing its electric pickup and pulling power.  The side play is not very important if it doesn't traverse wide curves.  BTW< from what I understand, the broken axle was  *THE* (only) powered axle in that loco.  That axle and the 1st axle are the only ones which are rigidly suspended in the frame (no up and down movement). The 2nd and 4th drivers are not contributing to the pulling power (just electric pickup). That is why they have sprung suspension (so they can always softly contact the rails).  This is a superb (although fragile) mechanical design on Kato's part.

IN the end, what Richie does to his model is his business but that won't stop me from criticizing what he did.  I'm not just blowing smoke - I provided facts as to why what he did is not optimal for this model's performance.

[up1950s]

The thing is not sprung , those 2 are floaters .

[SkipGear]

The thing is not sprung , those 2 are floaters .

Richie,
 The #4 driver should be sprung. It has a phosphorbronze leaf spring over top of each axle bearing on the rear axle. The #4 driver is sprung just enough to keep the loco from nosing under load. It is actually a very good design albeit very fragile.

[peteski]

Yes, it is what Tony stated. #4 is sprung but #2 is floating - I know that but forgot that #2 had no springing (it is allowed to freely flat up and down).   

[up1950s]

2 minutes go while grinding the inside of the frames on the other 3 axles to make clearance for brass tubes to incase the plastic axles I noticed the notched area around the number 4 axle . I found one of the leaf springs , the other is AWAL , but I will find it . Don't know if I will use that system though . The geared and brass sleeved axle is the most secure out of the four that's why I am slaving the other 3 . The process of pushing the rod pins in bends the wheel in the axle enough to loosen it a bit , thus causing problems . My plan is to make the axles almost but not too rigid with the geared TT a touch proud of the others . Side play is also desired . I don't know how much modeling I can do if I am swept out to sea , as I am just ten feet above sea level , the basement is less than that , and the swamps are a few blocks away .

[victor miranda]

get a biig sump pump a pile o sand bags and put the generator on the roof.
only the high waves can swamp you then.
luck, sir.

hi up1950s
did your missing spring get caught in a driver and cause the axle to pop?

on to conjectures
the gs-4 has some flaws in the design of the axle construction.
It depends on good quality manufacturing to remain functional.

The way Kato designed the flexability between the drivers and the frame
is a good way to solve the 'traction' problem most n-scale steam has.
lets call the whole thing a suspension system.

so when you combine the two ideas.
I find I am wondering what Kato had in mind.
Kato knows how to build stout and bullet proof locos.
They are quite willing to push technical limits

I have guesses and they are not satisfying.

victor

[peteski]

Here is the ingenious Kato's GS-4 design.



This drawing is approximate, just to demonstrate how the mechanism is designed. The wheels shown in green support the loco's weight. The transparent gray wheels are cosmetic. The gray driver wheels do pick up power while the trailing truck is strictly cosmetic. The approximate center of gravity is somewhere between #2 and #3 drivers.

The red arrows show the proportion of the loco's weight supported by each set of wheels.  As far as weight distribution, this loco acts like 0-4-0 loco.  The leading truck and the #4 (lightly sprung) driver support a negligible amount of loco's weight, the #1 drivers support a larger percentage of the weight but the majority of the weight is supported by #3 driver. The #3 driver is the only driven driver, and it also has the traction tires.   Thanks to this design, this loco has a surprisingly great pull!

I agree that the very thin driver axles are not IMO best design (as they can bend relatively easily) but overall, this is an excellent and innovative design.

[victor miranda]

if you have the front truck in that, you need to add the 4th axle as sprung also.

once that is done....
what reasons does kato have for making the axles the way they did AND
that helps the suspension system work?

I have guesses and they seem lacking.

victor

ETA to ask the question I had in mind....

[peteski]

if you have the front truck in that, you need to add the 4th axle as sprung also.

once that is done....
what reasons does kato have for making the axles the way they did AND
that helps the suspension system work?

I have guesses and they seem lacking.

victor

ETA to ask the question I had in mind....

Done!
I suspect that the small diameter axles were chosen to reduce the overall friction of the mechanism. Larger axles would have more friction. It has nothing to do with how well the suspension works. But that is just a guess on my part.

[up1950s]

So before I bother to cut 3 new plastic axles to shove  put 2 brass collars on each a thought came to me . Plastic has failed this many times for me , the steels axles will stay I think . What if I substituted the plastic for a wood dowel , still brass collard , but the thought is the Krazy Glue will soak into the wood and maybe make a better bond to the axle . The bearings take all the friction . The glue should make the wood lube proof . Your thoughts ?

[peteski]

Richie,
the plastic used in the original axle/gear piece is quite strong. It splits because it is unable to withstand the pressure of the metal axle pushed into it.

I thought that you would just place and glue the brass sleeves over the original split axles. That would have closed the split and prevent any further splitting.  But this sounds like you will make entire new hollow-tube axles. What type of plastic will you be using?  Styrene? Lexan? Delrin? I don't know if wood will be any stronger (as far as resistance to splitting goes.  It is an unusual solution for sure.  You do think out of the box! Wood will not give you any better bond to the steel axle. The weakest bond is on the surface of the steel (no matter what msterial is used for the axle tube).

Several years ago a plastic knob on my clothes drier also had a split sleeve (where the timer shaft plugs in).  Part of the sleeve actually separated.  I super-glued the piece back on then I took a heavy thread and wrapped it tightly around the width of the mended sleeve. Then I impregnated the thread with superglue. That repair is still holding!