Old and tired Bachmann 57xx

[snowy1051]

Hello, I have amongst my roster an old and weary Bachmann 57xx, model number 31-901, running number 5796.

Recently it has started to show its age by slowing down on its own. Then it will speed up again and slow down again. Now it just starts, runs for a few seconds and slows to a stop. There are no horrible noises. Is there anything I can do to restore it to its youthful exuberance please? I don't mind removing the body and having a tinker, but I have little experience of taking apart Bachmann locos. Many thanks. 

[PMP]

It’s an early split chassis version. There’s probably not a lot that can be done due lack of available spares. It sounds like a motor problem from your description, so sourcing a secondhand chassis might be an option, subject to knowing that the motor works.

[john new]

I don’t know the answer, but suspect a cause, hence adding this question. Does anyone do remags for these as IIRC the symptoms are similar to some that arise with old Hornby-Dublo motors, namely, lack of magnetic umph  (is flux the right phrase?).

 

Edited October 30, 2021 by john new
Corrected an auto correct change.

[cypherman]

HI,

If it is the split chassis engine it may not be the motor but the pick ups in the chassis. These engine take the current directly from the chassis and does not use wiper style pick ups. These are coated/lined with I think chrome to allow easy movement and good electrical pick up. Over the years this wears out and the contact becomes more unstable. There are 3 things you can do.

1/ Just use the engine as scenery.

2/ Get a replacement chassis. This goes for a faulty motor if that is the problem. getting a new motor I think will be difficult.

3/ If it is the pick ups you can replace them with scratch built wiper pick ups using brass pick ups from Hornby. It is not a difficult job. Here is how I did a split chassis 4mt.

 

Edited October 30, 2021 by cypherman

[The Johnster]

If it's a can motor with a worm drive and wiper pickups, everything can be replaced new from Bachmann.  You will need to quote the part numbers, which are on the user's manual sheet that came in the box with the model; not to worry if you don't have it as it can be downloaded free as a pdf from Bachmann's website.

[Going Spare]

The open-frame motor/worm for the split chassis version appears to be in stock at ekmexhibitions.co.uk. 

[SR71]

If it's magnet it will usually be accompanied by getting excessively hot while running. If it's a well loved model I'd start by stripping it down and cleaning everything, checking the electrical contacts as others have said, and then re-lubricate/reassemble.

 

In models that have been run and cleaned regularly over a long time there is the possibility that the dreaded black gunge can build up and reduce the resistance between the chassis halves (presumably due to the carbon content) and this gives a similar symptoms to a weak magnet.

 

In probability the above won't fix it but it only costs you time and if you manage to bring it back it saves buying a new chassis. There are many other common issues with split chassis over time, well documented on here by people more experienced than me.

[The Johnster]

There comes a point when a loco that has given good service over many years doesn't owe you anything, and sadly many of the old Mainline chassis never reach it, but light use and sympathetic driving, especially smooth stops and starts, will bring some into this category.  I would regard any Mainline/Replica split chassis loco including early Bachmann iterations that is still running as being on borrowed time, give them light duties, and consider replacement.

 

Once replaced, the old loco becomes surplus, and you might consider a Comet chassis and new motor for it just to establish that you can build such a thing; easier than you might think if you haven't done this before and very satisfying.  You will also be able to experiment on the body, perhaps for instance removing the top feed and associated plumbing, or even backdating to 2721 specification.

 

Mainline split chassis were, IMHO, a very good idea very badly implemented.  Split chassis kit or scratch build locos were in fashion in the 70s and 80s, and, in combination with the Portescap motor and gearbox, offered potentially very smooth and controllable slow running and perfect starts and stops.  This was difficult to achieve with 'conventional' wiper pickups because their bearing on the rear of the driving wheels was effectively a brake, dragging and preventing such smooth running. 

 

Mainline elected to use split chassis pickup when they entered the fray, and their locos were not bad runners for those days, but the design specified pancake laterally mounted motors in the fireboxes to preserve detail below running plates and a view of daylight beneath the boilers.  These pancakes were pathetically weak, and had to be run at high speeds to develop enough power to haul a sensible load, then be geared down by plastic spur gears to provide reasonable slow running.  As well as this, the materials used were unsuitable; the spur gears would have been better if they had been brass, and the plastic stub axles in plastic axle centres were not up to the job,

 

So the near perfect running of split chassis kit and scratchbuilds featured in the magazines of the day was never achieved, the chassis were draggy and I am sure this contributed to the wear problems that they infamously developed.  I had a 43xx that was destroyed in an hour of bad driving by a club member at a show; the locos were basically too delicate for many users and rapidly gained a poisonous reputation that still haunts the split chassis pickup idea in general.

 

Other manufacturers also went down the pancake motor/spur gear route, sometimes in conjuntion with tender drive, and some of the Hornby and Lima ones were pretty crude, but they were bombproof reliable.  At the cost of very poor slow running and jerky stops and starts.  Bachmann, to their credit, have addressed the problems with the can motor/idler gear/drive cog layout and a return to wiper pickups, which bear much more lightly on the wheels; the result is very smooth running and reliable mechanisms that take advantage of the availability of dirt cheap but very high quality motors that the Chinese produce in huge numbers.  The other manufacturers have followed suit, and what was intended in the 70s and 80s has been achieved; reliable mechs that give excellent slow running and smooth starts and stops, which in itself provides an easier life for the mech and increases it's service life, while preserving space for cab, underframe, and under boiler detail, at a price the market will bear.

 

Such performance can still be improved upon, even just by careful and sensitive tweaking of the existing chassis and ensuring that everything is running as it should, but a kit built brass chassis allows a choice of motors and gear ratios, and may be constructed to give even better slow performance and more haulage.  Current RTR standards are good enough for most of us most of the time, though, and I would not advise departing for them on layouts that use setrack curves!