Coaches Wobbling?

[Houndog1372]

Hi all,

I’ve recently replaced the axles on my Hornby Eurostar coaches, as the originals were too big and didn’t move freely.

I’ve also used the DCC concepts reaming tool on the bearings to ensure the axles are free moving (which they now are), however the coaches still wobble when running on my layout. 
I’ve also added additional weights into the coaches, and checked the back to backs. 
Is there anything else I can do to sort this or is it just a case of it being a poorly made model?

 

Thanks!

Edited January 31 by Houndog1372

[Miss Prism]

When you say 'shake', do you mean wobble from side to side?

 

[Houndog1372]

Yes thats a better description! 

[34theletterbetweenB&D]

I feel you may be up against the limitation of a train set model incorporating multiple vehicle articulation, with none of the stabilisation mechanisms that prototype trains of this type employ, and the slack clearances required for set track curves to boot.

[steve66]

I had a similar issue a few years back with an airfix B set they have small bogies so wobble on the centre pin, I used some thin foam/ sponge about 2 or 3 mm thick and just wide enough and long enough not to foul the wheels pushed over the centre pin it then acts as a rubbing plate if that's the correct term and still allows the bogie to pivot and calms the wobbling down, it did for me anyway. I didn't think of it it was passed onto me 

[Flying Pig]

Does the bogie itself wobble on the track or does it run smoothly and just the coach body wobbles?

[Houndog1372]

23 minutes ago, Flying Pig said:

Does the bogie itself wobble on the track or does it run smoothly and just the coach body wobbles?

The bogies all wobble when pushed on the track. 

[Flying Pig]

42 minutes ago, Houndog1372 said:

The bogies all wobble when pushed on the track. 

 

That sounds like the problem is with the wheels.  When you say you replaced the axles, did you buy new complete wheelsets or just axles?  If you refitted the wheels they may not be quite square on the new axles.  But it is quite possible that some were manufactured slightly off centre or not perfectly circular and will need replacing if you want smooth running.

[DCB]

My test is remove the wheels, put them on the track and roll them towards a  (2ft radius in my case)   point set to the curved road.   If it goes round fine,  if not the profile  is poor and the wheels will hunt from side to side often causing a wobble.  

4 hours ago, steve66 said:

I had a similar issue a few years back with an airfix B set they have small bogies so wobble on the centre pin, I used some thin foam/ sponge about 2 or 3 mm thick and just wide enough and long enough not to foul the wheels pushed over the centre pin it then acts as a rubbing plate if that's the correct term and still allows the bogie to pivot and calms the wobbling down, it did for me anyway. I didn't think of it it was passed onto me 

Oddly enough I have about 14(!) B set coaches (Don't ask, it was not intentional) and none wobble but they do suffer loose/lost  pivot pins  and need screwing on with 4BA?)  bolts, however my Airfix Stanier 57/60ft coaches are addicted to wobbling, extra weight low down helps and 1960 Hornby Dublo bogies cured one  (and looked horrible)  but replacement wheels are a problem, well cheap decent replacement wheel sets times 28 for the 7 set is  an issue ,same probably applied to the Hornby   Ireprofiled some Dapol ones in the lathe but doing 28 ,er 56  Life's too short.

 

[GWR-fan]

I roll the wheelsets individually along a flat surface to ensure that the sets run true.  If a wheel is drilled off centre or the insulating bush is misaligned then a wheel will wobble as it moves along the surface.  When I had largescale trains I would replace the stock plastic wheels on LGB coaches/wagons with either LGB metal wheels (which always ran true) or the less expensive Bachmann metal wheels.  However, I had to factor in that in a pack of four axles that the wheels would not run true on at least one axle per pack.  I would mix and match known good wheels on an axle to get a true running axle.  At $12.50 an axle there was considerable wastage to get a wobble free piece of rolling stock.

[Houndog1372]

I’ve replaced the standard wheels with the Hornby R8096.

The wobble seems to be more noticeable on the articulated bogie that both coaches share.

I would have thought the reamer tool would have solved the issue but it has not. 

[Miss Prism]

Body wobble is a common phenomenon on many RTR bogie coaches. The cause of the oscillation is a combination of bogie hunting (more apparent on straight track) and the lack of secondary (i.e. bogie to body) springing. The interface between bogie and body at the bogie pivot point is also an important factor. 10 years ago, CLAG took some video comparisons to examine the issue, the guinea pig being a Bachmann MkI. The video confirmed the roll plane frequency of the oscillation reduced considerably when secondary springing was present.

 

(Unfortunately, we never uploaded the video because we felt a more thorough examination was needed before publishing any quantified conclusions. And then time moved on.)

 

 

Edited February 1 by Miss Prism

[The Johnster]

10 hours ago, steve66 said:

I had a similar issue a few years back with an airfix B set they have small bogies so wobble on the centre pin, I used some thin foam/ sponge about 2 or 3 mm thick and just wide enough and long enough not to foul the wheels pushed over the centre pin it then acts as a rubbing plate if that's the correct term and still allows the bogie to pivot and calms the wobbling down, it did for me anyway. I didn't think of it it was passed onto me 

I’ve done this on a Lima Siphon that I fitted Mainline Collett 9’ bogies to; needed a bit of carving about under the floor and ran with a bit of a lean.  The foam collar cured the problem. 

[34theletterbetweenB&D]

4 hours ago, Miss Prism said:

Body wobble is a common phenomenon on many RTR bogie coaches. The cause of the oscillation is a combination of bogie hunting (more apparent on straight track) and the lack of secondary (i.e. bogie to body) springing. The interface between bogie and body at the bogie pivot point is also an important factor. 10 years ago, CLAG took some video comparisons to examine the issue, the guinea pig being a Bachmann MkI. The video confirmed the roll plane frequency of the oscillation reduced considerably when secondary springing was present.

I have been very pleased by the damping out of such oscillations provided by the close coupling mechanisms on those RTR OO models which have the Pullman gangway. Length adjustment of the 'rigid' coupling between the mechanisms is typically required such that all the gangway faceplates are in contact on straight track.

 

The train then moves as one piece and is stable: any deviation from this is an immediate alert to gross contamination on a tyre, usually seen as vertical oscillation. On such (rare) occasions we have the joy of the train halting to enable the faulty vehicle to be detached and set aside. It would be lovely if this might be accomplished without the hand of god, but such refinement has yet to be achieved.

[billbedford]

On 01/02/2024 at 06:43, Houndog1372 said:

I’ve replaced the standard wheels with the Hornby R8096.

The wobble seems to be more noticeable on the articulated bogie that both coaches share.

I would have thought the reamer tool would have solved the issue but it has not. 

 

Unless, of course, you've reamed the bearings too deep and the wheel sets are slack in the bearings. 

[Kylestrome]

One way of stopping bogie vehicles from rocking is to add two stabilising pins (in this case screws) to one of the bogies. This allows the bogie to rotate, to compensate for track undulations, but stops the body from wobbling side-to-side. See the last photo in this post:

 

https://www.rmweb.co.uk/forums/topic/118922-kylestrome’s-4mm-workbench/?do=findComment&comment=4302300

 

David

 

Edited February 2 by Kylestrome

[Mallard60022]

Do you think you may have over-reamed out the Bogie Axle Holes and the Bogies have too much play?

Old Airfix and particularly the dirt cheap Dapol MR Coaches suffer from this in a horrible way as in the latter, the Bogies really are horrible and plastic wheels...yuch.

Phil