My Standard class 4MT waddles like a duck.

[paulstephens]

My Bachmann standard class 4MT waddles like a duck at least a cm each way as it moves down the track. Anybody know how to cure it?

[DCB]

4-6-0?  They  do that.  Split chassis type?    The ones with no visible pick ups and no sign of the axle  ends when viewed side on .   The wheels come loose..    The pre Bachmann, "Mainline " branded ones the wheels slipped round and the valve gear tied itself in knots.    "Bachmann" have square axle ends so the wheels can only slip few degrees but can fall off!.    Usually the rear wheels work themselves out wards  making them wide to gauge and introducing a waddle.
You can get new plastic axles to get a better grip on the wheels and stop them working loose for a while. I have super glued the wheels to the axles by drilling the hole in the square right through the axle and a hole at right angles to let excess glue out, If not done the wheels often don't go all the way on.    Disadvantage is the worn axles don't necessarily keep the wheels aligned "Quartered" at 90 degrees  to those on the other side or in phase with those on the same side.
Root cause of the loose wheels is the pick up through the stub axle, this is not great and leads to localised heating which softens the axle.   I fit springy brass pickups between chassis side and the backs of the driving wheels     I also reduce the side play on the rear axles on the 4MT with washers between axles and chassis half.
The 2-6-4 and 2-6-0 are not split chassis and not usually affected.  I had the wheels fall off a brand new unused  split chassis Bachmann Manor after 15 minutes of running in, I changed to a Hornby chassis. but suitable replacements for the 4MT 4-6-0 are very rare.

[34theletterbetweenB&D]

1 hour ago, paulstephens said:

Anybody know how to cure it?

No, and as above first it is necessary to know which of four potential models this might be.

Bachmann split chassis 4-6-0, problems as described above.

Bachmann 4MT 4-6-0 (has a decoder socket) No experience

Bachmann 4MT 2-6-0 (has a decoder socket) Few if any problems

Bachmann 4MT 2-6-4T (has a decoder socket) This last is also a known problem child thanks to the speedo drive representation

 

 

[Michael Hodgson]

2 hours ago, paulstephens said:

My Bachmann standard class 4MT waddles like a duck at least a cm each way as it moves down the track. Anybody know how to cure it?

 

Just fit "Mallard" nameplates to it.

[Blandford1969]

Have you been on one of the real things they ossolate like mad at times! :) 

[cypherman]

Hi Paul.

The reason why your engine is waddling like a duck is the plastic inserts in the driving wheels. Unfortunately the plastic over time expands and warps the wheels. Pushing the middle of the wheel plastic to expand outwards causing the waddling effect. This effect is not just on the 4-6-0 STD class 4 but also happens on any of the early Bachmann engines with these types of wheels. There are a couple of things you can do.

1/ Get a replacement chassis and hope the wheels on that are Ok.

2/ Try and cobble together a new set of wheels. This is extremely difficult if not impossible as the engine is of the split chassis type.

3/ And this is what I did on all mine. Get a sharp knife and cut out the plastic inners. Do not worry about the wheels the metal is thick enough to maintain the wheels integrity. You might have to straighten wheels a bit but that is quite an easy job. Then cut out the wheel weights from the plastic and glue them back on in correct positions and paint the wheels in a suitable colour of your choice. I used matt black. From a short distance you cannot seen the problem with the wheels unless you are actually looking for it.

[The Johnster]

Sorry, Cypherman, I'm having a particularly slow-brained day today, even by my standards.  By the 'plastic inserts' and 'plastic inners' do you mean the 'hub', crank, spokes, and balance weights?  As this doesn't make sense to my fuddled mortal remains, as when you glue the balance weights back on to the inside of the wheel rim, what physically connects the wheel rim to the axle?  Or do you mean that the plastic assembly including the balance weights and spoke &c is to be glued back in the correct place, which makes more sense, and the 'plastic inserts/inners' are in fact some sort of plastic sleeve between the axle and the wheel centre plastic crank/spoke/balance weight piece. 

 

Again, apologies if I am being a bit slow on the uptake.  Sometimes I sits and thinks, but today I just sits...

 

I'm interersted in this work-around as I have an old Baccy split 43xx chassis underneath one of my old Hornby large prairie bodies.  It is a decent smooth runner but the rear wheel centres are beginning to distort and dish outwards in the way you describe and it is clearly on borrowed time unless I can rescue it.

[Halvarras]

Is this of any use?

 

https://www.ekmexhibitions.co.uk/home/BR-4MT-4-6-0-WHEEL-SET-Split-Chassis-p257692995

[cypherman]

On 09/09/2023 at 00:59, The Johnster said:

Sorry, Cypherman, I'm having a particularly slow-brained day today, even by my standards.  By the 'plastic inserts' and 'plastic inners' do you mean the 'hub', crank, spokes, and balance weights?  As this doesn't make sense to my fuddled mortal remains, as when you glue the balance weights back on to the inside of the wheel rim, what physically connects the wheel rim to the axle?  Or do you mean that the plastic assembly including the balance weights and spoke &c is to be glued back in the correct place, which makes more sense, and the 'plastic inserts/inners' are in fact some sort of plastic sleeve between the axle and the wheel centre plastic crank/spoke/balance weight piece. 

 

Again, apologies if I am being a bit slow on the uptake.  Sometimes I sits and thinks, but today I just sits...

 

I'm interersted in this work-around as I have an old Baccy split 43xx chassis underneath one of my old Hornby large prairie bodies.  It is a decent smooth runner but the rear wheel centres are beginning to distort and dish outwards in the way you describe and it is clearly on borrowed time unless I can rescue it.

Hi Johnster,

The wheels are all metal with the plastic inserts sitting inside the front of the wheel. In like a shallow dish. The plastic inserts are about 1.5mm in depth. When you remove them you still have the rest of the wheel which includes metal wheel spokes that match the plastic inserts. You take out the inserts and cut off the balance weights and glue them back onto the wheel in the correct position The metal wheels are more than strong enough to run the engine on. Once painted black they are very hard to see any difference on them when just watching them run. I have done this to all 5 of my Bachmann engines. The only one I have not done it to is my one and only Mainline one. As this has solid metal wheels. Why Bachmann did not keep the all metal wheels and put square axle mounting point on the I do not know. But it would have been better all round if they had.  Any way I found this post on this same topic I did in 2019 here explaining what to do. Sadly the pictures went in the great photo death that happened here. So I had to find them again and have added them here. This was the first engine I did and it was only after I had finished and took the photos that I realised I had put the weights in the wrong place and had to take them off and move them to the right place. These pictures show the wheels after the inserts have been removed. So all it cost was a bit of time and superglue.

 

Edited September 11, 2023 by cypherman

[cypherman]

20 hours ago, Halvarras said:

Is this of any use?

 

https://www.ekmexhibitions.co.uk/home/BR-4MT-4-6-0-WHEEL-SET-Split-Chassis-p257692995

Hi Halvarras, That's an excellent link. I have added it to my list of suppliers.

Edited September 9, 2023 by cypherman

[paulstephens]

Thanks everybody, yes it is a split chassis model. I'll try the plastic insert exchange, if I read the response correctly that is what you are proposing?

I will also make sure the back to back on the wheels is correct. I did muddle with the quartering but it wasn't easy. I have corrected the wobble abit but not quite enough to my satisfaction yet.

[cypherman]

1 hour ago, paulstephens said:

Thanks everybody, yes it is a split chassis model. I'll try the plastic insert exchange, if I read the response correctly that is what you are proposing?

I will also make sure the back to back on the wheels is correct. I did muddle with the quartering but it wasn't easy. I have corrected the wobble abit but not quite enough to my satisfaction yet.

Hi Paul,

There is no problem with the back to back as the wheels slot into the axels and need to be fully pushed in. Once pushed in they are at the correct distance. One thing that was not mentioned is that these older engines are prone to splitting their axles. I believe replacement axles can be bought from Peters Spares if needed.

https://www.petersspares.com/

But with a bit of luck yours will be ok.

[The Johnster]

On 09/09/2023 at 11:29, cypherman said:

Hi Johnster,

The wheels are all metal with the plastic inserts sitting inside the front of the wheel. In like a shallow dish. The plastic inserts are about 1.5mm in depth. When you remove them you still have the rest of the wheel which includes metal wheel spokes that match the plastic inserts. You take out the inserts and cut off the balance weights and glue them back onto the wheel in the correct position The metal wheels are more than strong enough to run the engine on. Once painted black they are very hard to see any difference on them when just watching them run. I have done this to all 5 of my Bachmann engines. The only on I have not done it to is my one and only Mainline one. As this has solid metal wheels. Why Bachmann did not keep the all meta wheels and put square axle mounting point on the I do not know. But it would have been better all round if they had.  Any way I found this post on this same topic I did in 2019 here explaining what to do. Sadly the pictures went in the great photo death that happened here. So I had to find them again and have added them here. This was the first engine I did and it was only after I had finished and took the photos that I realised I had put the weights in the wrong place and had to take them off and move them to the right place. These pictures show the wheels after the inserts have been removed. So all it cost was a bit of time and superglue.

 

 

Thank you Cypherman, it makes a lot more sense now!