Bachmann 9F unflanged driver problem

[34theletterbetweenB&D]

Yesterday evening one of my 9Fs truly left the road on a  crossover, and managed a head on with another train. Well, it had never shown any sign of doing that before so was set aside for daylight study.

 

Cause is wear in the chassis block allowing the unflanged driver enough lateral freedom by rocking that it can now get the tyre off the rail on a facing point, with a mighty bump when it reaches the crossing, and we're all across the track! The unflanged wheelset is effectively running on the gear rather then in the chassis block locations. Inspected its twin, purchased at the same time which has had (as nearly as I can estimate) the same running over the past 13 years, and it is in much the same state, though still behaving well.

 

I can prevent the derailment by packing behind the wheelset with washers to eliminate the lateral play, that way the tyre cannot slip off the rail. But this does nothing for the fact that this wheelset is actually supporting the chassis block on the gear set. I rather think some bushing will be called for.

[34theletterbetweenB&D]

That's a useful collection '313201'.

 

If I go for modding the chassis block the plan will be to cut quite a lot of the Mazak casting away around the 2nd and 3rd axles and install a replacement subchassis; that will be a major piece of work. Now I am an (increasingly) idle beggar, so if I happen upon a reasonably priced s/h model to donate a mechanism I may well jump that way.

 

The K3 is one of my older Bachmann steam models currently operating and mine have done enough running to show some wear, led by flanges taking paint off the footplating and causing shorts; but by filling the axlebox wells with white metal, wear is minimal in that area (and the same treatment on all the other Bach mechanisms that came out before they adopted brass axle bushes on their new introductions).

 

3 hours ago, 313201 said:

...Other problems I had included the little spindles or mini axles whichever term you prefer were coming out of the block sideways so that the gears between the wheels and motor would come loose.  The worst incident and the most fiddly go deal with was the gear at the top of what I referred to as the gear tower under the motor coming loose so I had to again slide washers onto that to stop side movement of the gear aswell.

 

In order to prevent further problems with the gear axles I glued a piece of very thin brass sheet over the axles, being careful to keep the glue away from them then so the brass would not be easily noticed I painted it black....

 

Now these gear shafts. I was dubious of this construction when it replace the plastic motor cradle and gear tower unit, but to date no troubles. And that's on about fifteen different designs, and despite my tinkering with taking gears out and reinstalling them, (usually to install the odd washer or three to keep them full meshed across the gear faces) combined with a lot of running. My precautionary solution on those locos which can use more weight is to drape a customised inverted 'U' of lead sheet over any accessible gear shaft ends: it can do two jobs for me. (I was beaten regularly with the value engineering stick early in my career...)

 

 

[peach james]

If the loco has done enough miles (real miles...) to show wear to this extent, might it be worth considering a replacement chassis?  I'd guess that in order to show that kind of wear, you are looking at 50+ miles of actual travel...and that a Comet or similar aftermarket replacement set of frames might be the easiest long term solution.  Sometimes the bodge isn't worth the effort, and I suspect that if you have worn out one part of a RTR mechanism, you are likely close to the end of life of the whole thing.

 

It's not like the real thing didn't have the same sort of problem...

 

James

[34theletterbetweenB&D]

2 hours ago, peach james said:

If the loco has done enough miles (real miles...) to show wear to this extent, might it be worth considering a replacement chassis?  I'd guess that in order to show that kind of wear, you are looking at 50+ miles of actual travel...

And the rest! The estimated mileage on the 9F is somewhere in excess of 300 hauling a circa 2.5kg train, so I do feel I have had my money's worth. I operate a lot by most people's standards, that's the why of having a  layout! From long term experience of kit chassis, given equivalent care in use and servicing, the currently produced RTR OO has equivalent mechanism longevity. (Of course that comparison may be more of a reflection of the standard I am able to achieve in building kit chassis...)

 

I am inclining to  a RTR replacement mechanism, something I have done frequently to repower both kit bodies, and older RTR bodies with clapped and/or never very good unpower bogies and split chassis mechanisms. But this will be the first of the current generation of Chinese made RTR OO to get a repower...

[The Johnster]

If a current design RTR chassis can manage 300 actual miles, equal to 22,800 scale miles, I suppose that’s not bad.  It is re-assuring to someone like me because it means that my locos are unlikely to wear out during my lifetime on my small BLT despite frequent running, especially after wearing out a few 1980s Mainline chassis that had only ever run at a few exhibitions; they wore through to the top of the axle channels.  

[34theletterbetweenB&D]

My Bachmann WD's are worked at much the same rate as the 9F, but seven years longer in service are still going. They are near twice the weight as supplied, all the Mazak ballast inside replaced in lead, and have the second and fourth axle springs stretched so that 80% of the loco weight is carried on the saddles rather than the frame casting, mainly to protect the gear axle. The driver tyres show a hint of copper now on the worn track from rail contact.

 

I never had any Mainline to speak of, but wore through the Bachmann split chassis plating at a terrific rate despite regular cleaning and light relubrication: nothing can be done on the tyres, once the plating was largely gone from rail contact 'all used up'. But hey, the replacement chassis were cheap at the time, so just bung a new one in. My first B1 reworked to represent Hitchin's 'Madoqua' is now on it's fourth mechanism, the last  a current Bachmann, and should outlast the previous three combined...

[tomparryharry]

I executed a very similar repair on my Heljan D95xx. In this case, I used C washers, packed behind  the wheel, sufficient to stop the centre drivers moving laterally. What might happen, however, is that the centre driver is rubbing up against any railhead, and is being forced off by the turning motion. May I suggest that a slight 'dressing' of the wheel to remove anything such as a burr is removed.  

 

The other remedy, perhaps, is to ensure that the 4th pair of wheels actually follow the 2nd pair of wheels. Are they in line, or offset? Can the 4th pair of wheels move about, as the centres have? Finally, check the coupling rods. Are they helping to keep the wheelsets in line?

 

Hours of endless fun!

 

Best wishes,

Ian.

[G-BOAF]

Shame as in terms of mechanism, haulage capacity and detail, the Bachmann 9F is first class.

It does highlight the need for brass bearings. If this was a bearing issue you could fit new bearings or (given how these parts are supplied) new wheel sets.

I won't be running my two 9Fs as much as that, but its somewhat alarming that such wear can develop, and highlights a flawed mechnical design.

And of course Bachmann don't do replacement chassis...!

[MikeParkin65]

1 hour ago, 313201 said:

Hi 34 B&D

 

The only other option would be to kitbuild a 9F loco chassis.

Or a Hornby loco drive version

[34theletterbetweenB&D]

1 hour ago, 313201 said:

The only other option would be to kitbuild a 9F loco chassis.

In the long ago, I had a part in constructing one, and there wasn't a kit back then. One of the things that taught me is that the  Bach 9F is fully worth the money just for the brake gear fit. Of course we hadn't been as smart as Bach's designers and slightly stretched the coupled wheelbase to make a little more space to fit all the tackle in: all metal fully conductive brake gear representation right next to all those closely spaced wheels, nightmare. It looked good...

 

1 minute ago, MikeParkin65 said:

Or a Hornby loco drive version

Actually I still have two of the chassis from the final Hornby tender drive version, which I motorised on the 4th axle. As far as I can see the rods on the current Hornby loco drive are identical. Now that matters, as the rods on mine had repeated failures after a couple of years of use, mainly repeated breakage of the rivets that formed the rod joints, but we also had a motion bracket detachment and a slide bar kablooie. The plating was coming off the tyres after the first year too, and the brass underneath tended to get dirty rather quickly.

 

The discussion in this thread has been useful in getting me settled on the best course. I'll just buy another Bach 9F, they are worth the dough. Or perhaps Accurascale will announce one...

[harry lamb]

Good evening, In the first instance we must take into account that what we purchase will wear out rapidly and require replacing. This is what business is all about. It's called 'built in obsolescence'. So, surprisingly to some, they may have missed the obvious as It's been going on for donkeys years! However, purchasing and flogging the 'favourite' to death and having to replace it at an inflated price is what keeps these companies going. So, they are NOT going to start manufacturing large amounts of spares just for home installation when a replacement 'new' product would  possibly provide a greater customer 'pull'! Therefore, I would like to think that all these 'failures' could provide a basis for several 'Barry' type layouts in the future featuring the life expired locomotives of all the variously 'fueled' types just spread about awaiting their own demise! 

Edited April 25, 2020 by harry lamb

[truffy]

‘Designed obsolescence’ may apply to washing machines, but in the case of model locomotives I suspect it’s more a case of design/build to a price point. 
 

Even washing machines from ‘the good old days’ wore out eventually. 

Edited April 25, 2020 by truffy

[34theletterbetweenB&D]

9 hours ago, harry lamb said:

... Therefore, I would like to think that all these 'failures' could provide a basis for several 'Barry' type layouts in the future featuring the life expired locomotives of all the variously 'fueled' types just spread about awaiting their own demise! 

In my case, since a loco shed of any significant size has to have one or more locos on 'shed day' for routine washout and inspection, and also those receiving fitter attention to repair or replace failed or degraded components, that's where my 'life expired' will go. (Got to actually build my 'Top Shed' first.)

[doktorstamp]

There is a longish video on YouTube giving a history of the 9F.

Link here; 

Watch, listen, and digest. the real life ones suffered from similar problems.

 

regards

 

Nigel

[The Johnster]

On 25/04/2020 at 01:26, harry lamb said:

Good evening, In the first instance we must take into account that what we purchase will wear out rapidly and require replacing. This is what business is all about. It's called 'built in obsolescence'. So, surprisingly to some, they may have missed the obvious as It's been going on for donkeys years! However, purchasing and flogging the 'favourite' to death and having to replace it at an inflated price is what keeps these companies going. So, they are NOT going to start manufacturing large amounts of spares just for home installation when a replacement 'new' product would  possibly provide a greater customer 'pull'! Therefore, I would like to think that all these 'failures' could provide a basis for several 'Barry' type layouts in the future featuring the life expired locomotives of all the variously 'fueled' types just spread about awaiting their own demise! 

This is built in to the 'Chinese model' of commissioned manufacture; the commissioner in the West orders a set number of models to a specification that they have designed in-house and produced as a set of CAD drawings, and the Chinese contractor sub contracts out to various component manufacturers, arranges for the components to be collected at an assembly plant where the models are assembled and finished, then to a packaging facility and finally into the container for shipping.  These requires set numbers of each component to be produced to assemble into the set number of models ordered

 

Thus there are no spares.  If 3.000 locos are ordered then 6,000 cab side window parts are made, no more, no less.  And there is no demand for spares from the commissioners here, as they cannot afford to pay for them and to pay for storage and the organising of distribution of them either.  Parts are bespoke to each model and a large variety of stock would need to be carried, unlike, say, early Triang where two chassis blocks and one set of motion, with a common motor and worm/cog drive, did for everything.

 

Our commissioning companies, which include Bachmann, Hornby, et al, could specify parts less prone to wearing out, such as brass bearings for motion pins and all brass worm and cog drives, metal slide bars and crossheads, and some do to some extent, but there is a cost that has to be passed to the customer in a competitive market.  I am fortunate in that my layout is a small BLT, loads are light and speeds are low, as are mileages, and I fully expect my RTR locos to outlast me despite regular and frequent, daily, use, but if you have a large tailchaser with long trains running at scale speeds wear will be a factor in your locos' lives.  

 

Modern RTR, which is as good as anyone has a right to expect for volume produced models at the price level even though it is increasing, is designed to run until the sealed can motor wears out.  A replacement model may well work out as cheap or cheaper than the price loading incurred in providing spares to repair the old one, and even be as environmentally acceptable, but this does not take account of any detailing or weathering you may have done yourself to the model at your own cost.  The obvious thing to do is to buy a replacement and bodyswap, leaving you with a spare body which is of very little use to you and may be knocked out on 'Bay or provided with a 'Bay chassis, or used as a donor to build a Comet type brass chassis, or used with an older chassis you happen to have around, or become a shed lurker with the chassis you've just swapped out.

[34theletterbetweenB&D]

2 hours ago, The Johnster said:

...Thus there are no spares... The obvious thing to do is to buy a replacement and bodyswap, leaving you with a spare body which is of very little use to you...

While agreeing with the general thrust of your post, I would make one comment.

 

In recognition of the general lack of spares, my policy has been to acquire a 'breaker' as cheaply as possible for the 14 essential steam* classes that operate most of my layout traffic. I usually sell the bodies from these, and have never yet had trouble shifting them, and this is because of the lack of manufacturer spares. Modellers wanting either to replace a damaged or ruined body or to have a livery alternative. or a body to go with a kitbuilt mechanism, are surely out there; and happily as far as I am concerned the 'manufacturers' are not serving this market.

 

My once derailing 9F is back in service operating on the 'breaker' mechanism, it's actually a new 'breaker' to go in the reserve cupboard hat I am now patiently looking for...

 

*I am not bothering with the diesels. My oldest centre motor mech is still going as well as ever, 28 years from purchase, with no service attention whatsoever. That was a deliberate experiment on seeing the style of construction and grease packing, and this loco spent a couple of years running outdoors too, a very much more demanding environment than an indoor layout. The manufacturer got that design very wrong from a repeat sales perspective, much too robust...)

[The Johnster]

I operate a boiler washout policy, which rewires keeping track of ‘operating timetable days’ and withdrawing the loco from service every 10 working days.  This is not only prototypical and therefore fun in it’s own right, but has other advantages as well.  It means, for a start, a justifiable reason for more locos, and gives an opportunity to regularly check and maintain locos.  An operating day at Cwmdimbath lasts about 14 real days, not necessarily consecutively.

 

This also means that locos are regularly exchanged and variety is introduced, though I have favourites of course.  But it is closer to the way the real railway operated.  

[34theletterbetweenB&D]

Same sort of plan with me for the steam models. Principal reason is for lubrication of all outside motion joints, monthly for the road engines that run real mileage, quarterly for little shunty types that don't go very far. Keeps rod joint wear down to a minimum. General check for tyre and pick up cleanliness at the same time. Internal lubrication, two year intervals between checks, and I may increase that as the grease lubrication on the axles and gear trains appears very effective overall.

[The Johnster]

Watch the cumulative mileage of your shunty types.  A loco that is in constant back and forth use might rack up a fair bit, though admittedly at lower speeds, and the amount of cumulative wheel revolutions is higher on locos with smaller driving wheels such as J72 and J94.  There is probably some sort of formula for working this out, and if you can be bothered you're a better man than I am, Gunga Din.  If one were to calculate wear rates in this way, total number of wheel revolutions is probably a more accurate indicator than scale mileage.  Neither figure accounts stress from loading or friction/heat build up at speed, and working it out accurately is probably irrational and overkill when a regular time interval based check is adequate for this task, but application of this sort of thinking might lead to some surprising results with your marshalling yard pilots or any industrials (even smaller wheels).

 

But wear in traffic usage is certainly a matter to be taken into consideration, even on my small BLT.  Two days Cwmdimbath time out of traffic for boiler washout is quite a while in real time, and I like having a variety of things to do according to my mood.  I might one evening fancy an operating session, another detailing or scenic work, then 'the project', whatever it is at the moment,  and another still for stripping down, cleaning, lubing, checking, and re-assembling locos.  

 

I reckon a leisurely full strip down, deep clean, and re-lube takes about 45 minutes if no other work is required, add another 10 minutes for outside cylinders and motion, so it is not onerous so long as you do not have a queue of locos waiting for it; the boiler washout system copes well with this.  It promotes reliable running as well, though I find the biggest aid to this is frequent operating sessions.  It's win win, you get good running and the work is satisfying and rewarding in it's own right, and you gain a more intimate knowledge of each of your locos, their strengths and weaknesses, and personalities.  If any of mine stop running, I usually know why before I even look at them, though this level is harder to achieve on a big layout with a large stud of locos.

Edited April 27, 2020 by The Johnster