Bachmann axle problems

I don't know why they do this,but it is a VERY common problem ,and the plastic axle-centres aren't available as spares..
It is also the same with their Mainline predecessors,where this is virtually guaranteed to happen,[bear this in mind if contemplating buying a secondhand Mainline loco!],the only feasable repair is to turn-up some replacement axle-centres from tufnol in a lathe,or,as you say,confine the Bachmann chassis to the scrap box and build an etched kit replacement,Comet kits spring to mind...with wheels from either Romford,Sharman,Gibson,or Ultrascale......

Is this a similar problem to the old mainline warships which were prone to breaking the drive gears and thus immobilising the loco? (also white plastic).
Could it be due to slight expansion and contraction of the axle thus cracking the surrounding virtually interference fit plastic?
Heljan also use a plastic drive gear on the class 47 and maybe others too, hope they are better made but i doubt it.

I've had several split frame chassis fail over the years due to the same problem.
I think it might be caused by lubrication, oil reaching the joint and then aiding seperation. This normally happens on a favourate loco, with a difficult to replace chassis,
one of mine is Sherwood Forester, a parrelled boilered Scot with lined cylinders.
Rebuilding the chassis isn't the problem, but getting the journals to remain together during running is another problem.
Another one for the display case.

I had a similar problem problem with US locos from Bachmann a long time ago. They used a rigid nylon based plastic, I think it was called Ralloy, that was supposed to be a self lubricating plastic. Turns out you have to use an inert grease, lithium based, not oil with it. The oil attacks the plastic over time and as the plastic dries out it cracks due to it's weakened state. Most of the US models has steel half axle in each wheel center which was plastic as well. The driven gear drove a the half axle joiner which was made of this plastic. The half axles were spline to push fit into the axle joiner and these just split over time. Never having had an early British Bachmann I don't know if they used the same system. I did have Mainline/Palitoy LMS Royal Scot but it expired many years ago which caused my switch to US modelling. Now it's back to British and my enthusiasm has returned for the hobby.

Ozzie21

QUOTE (Great Northerner @ 1 Mar 2006, 06:58)I've just found some old Bachmann locos (LNER V1 and V2) which have been at my dad's house for a while. They have not been touched for at least 10 years, and all have the same problem - the white plastic axles have split, and the wheels fell off as soon as they were taken out of the boxes. The locos have been stored at room temperature, and away from sunlight. Does anyone know why this happens? Although Bachmann replacement chassis are available I'm tempted to have a go at building an etched brass chassis kit and use Romford/Markit wheels as replacement Bachmann units will probably suffer the same.
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I've managed to rescue the V1 by canibalising the axles from the V2 that had not split. Comet do a V2 chassis, so will place an order for this. They don't do a chassis kit for a v1/3 tank though

QUOTE (Great Northerner @ 1 Mar 2006, 06:19)Do the newer Blue Riband locos have the same type of axles, or do they now use metal?

Blue Riband locos have an entirely different design of chassis,-a more conventional solid block casting with one-piece metal axles and metal wheels with an insulating bush at the hub and wiper pick-ups bearing in their rear faces,so they don't suffer from the problems that beset the earlier split-frame design chassis ....

Good tip about the grease,Ozzie21

It's strange the problems with British Bachmann split chassis locos. I've had around 40 US Bachmann steam locos over the years and they have used a split chassis all this time. Even the newest models, USRA heavy mountain and C&O J2 mountain both have a cast metal boiler, and the USRA light mallet 2-6-6-2 use the split chassis. Guess I'll have to find a couple of these British Bachamnn's and see what the problem is. So which ones do they still make with the split chassis? It's train shopping day tomorrow so early replies if possible.

Ozzie21

Looking at the Bachmann service sheets and model codes, it's any steam locos with the reference 31-xxx, so this will be Patriot / Scott / Jubilee, Ivatt tank, J72, V1, V2, B1, J39, Manor, 43xx, A4, 04 diesel shunter, 4MT 4-6-0, Lord Nelson, some very early production runs of the pannier tank. Possibly also 166 and 158 DMUs.

Having dismantled another loco, there are differences in the plastic axles. Some of the wheels have a square peg which has a corresponding square hole in the axle (B1 and V2, possibly others) - bit like a Romford axle only in reverse, whilst my pannier tank has a round peg (possibly explains why there is so much twisting movement available and why the wheel quartering has never been any good on my example).

It appears that the split frame locos are being phased out - the J72 and Royal Scot were two of the earliest Palitoy Mainline locos, yet other early Mainline locos e.g. Peak diesel and 22xx Collett goods have been brought up to the new Blue Ribband standard. The 4MT 4-6-0 has been dropped.

As I understand it mainline used a smaller axle section and with the inherited problems Bachmann revised this to a 6mm axle from 5mm and they made replacement chassis available. These are just about all gone and I had the last V2's and V1/3 from Hattons, Ebay can be a source of new unused chassis but mostly for the Lord Nelson other chassis types seem to have gone completely.

Bachmann no longer sell chassis much to my and others disappointment. The new B1 is a straight swop for the old is a swap for the Mainline. still no chassis available.

It is a fix to go Comet or similar but it costs more than a really good new replacement, Bachmann should be able to supply axle inserts but that was some time ago they may have lost interest now the split chassis is heading for history, my father is a dab hand at this job but it is fussy and takes patience.

The fault is typical and even a replacement chassis can fail in no time, what I do now is keep them for spares, for instance I now have a Hornby 4MT with a damaged body so it now has a Mainline body and a Bachmann tender body, strange as it seems there are spare Hornby chassis but no bodies whilst you can get Bachmann bodies but the chassis are u/s.

Buy a new Hornby B1 there are bargains to be had and it is 1000% better than the split chassis Bachmann, the new Bachmann is good but not as good as the Hornby.