Many thanks for the replies. I have done more since my posting and, James in FL, I agree with what you say below


"Take a good look at the position of the running gear on either sides' orientation of the wheels to each other and position of the wheels relative to the opposite side. If doing this for the first time take a picture, if you can, of each side before you open the halves."

"This is the tricky part, get your wheels back in the chassis just as they were when you opened it, those pictures can pay off here. Get your quartering perfect 90 degrees."

I have taken the wheels out many times to clean the axles and axle pockets for good contact...as well as careful greasing of the gear wheels. When I say "take out" I did not remove the front pistons so the wheel set is really just pulled out of the way, not totally separated. I think I have not paid enough attention in the past as to how the wheels go back. I think I had them offset i.e. the running gear or conn rods were not symmetrical on both sides. There is enough play or tolerance for this to happen, I think. This time I was very careful how I put them back and made sure the rods were in exactly the same configuration on both sides of the loco.

It's running much better now and so far so good.

I have had several issues with this loco but have been able to work through them. Overall I like it and think it has been worth the effort.

I never did separate the chassis halves; the motor is running very smoothly and did not want to have trouble getting it back together.

Cheers,

I'm troubleshooting another problem. The loco is making a noticeable "chugging" noise with a definite vertical wobble. Its as if something is out of balance or alignment. I have lubed very well the connecting rods, wheel cover off and gears well lubed. I wanted to oil the motor bearing but I don't think that's it. Any offers? Thanks 

Can someone confirm that in order to separate the two halves of the chassis on this loco and get to the motor you remove the 3 philips screws and pry it apart? Is there anything else holding it together?

Thanks.

This is the best site I have found for Hornby Minitrix N scale locomotives.

http://www.jfheath.co.uk/ngauge/index.shtml

Hornby stopped selling these over 20 years ago. They can only be found now on eBay etc.

If I prop up the front so all loco wheels are off the rails and power is only coming through the tender pickups, wheels run perfectly in both directions.

Any thoughts or suggestions welcome.

I am troubleshooting an N scale loco..not Bachmann I must admit but i think the principles are the same. It runs MUCH smoother and faster backwards rather than forwards. I have done all the usual stuff, cleaning, lubricating everything...very sparingly...and its the same.

It is a Hornby Minitrix Evening Star.

Thoughts anyone?

Agreed - however it does appear to me that the traction tyres are really not doing a whole lot if they a) lift the other wheels up so that the electrical contact is poor since b) this will also decrease the traction from the other wheels too. It appears that they are really defeating the purpose.

Skipgear: To prove your point I took off the traction tyres and put the wheels back on..she's still running perfectly...no jerk, no erratic and no hestitation over the points as before. As I type she's pulling my longest train with 17 goods wagons..and no wheel slip. I will leave the traction tyres in my spare parts box

THANK YOU!   ..you're a life saver....I have fought with this thing for way too long....now its better than ever...

Thanks for you insight "skipgear"...I'm sure you are right 

Correction - its the 3rd set back from the front:

http://www.bachmanntrains.com/home-usa/dwg/dwgs/58052.pdf

Remove the back boggies and the small Philips head screw on the plastic gear cover. Once removed the wheels and gears are exposed. The 3rd set back from the front lift off....they are just set in there and not connected to anything unlike all the others.

I thought I would start a new thread since I believe that I have found something rather important. My loco is very sporadic, one day its OK then a few days later it runs really erratically. Today it ran very badly I so I took it apart and cleaned the axles and axle sockets for the 1000th time it seems. Just for the heck of it I put it together with the 2nd from the front wheel set missing. This wheel set comes out easily and is not connected to any of the con rods. It also has the traction tyres on it. It ran SUPERBLY with that pair of wheels missing, smooth as silk, never faltered, even when run very slowly. It never hesitated even on the points. I have never seen it run this well. I had it running all day like this. I put back the wheel set and it ran erratically and jerky all over again.

So it appears that there are other reasons for very poor performance on this loco other than poor pickup. This wheel set has a gear wheel in the center and connects together two other gear wheels on this loco. Its almost as if connecting together these two gears binds and ceases the motion now and then. I now need to get it running this well with that wheel set back in the chassis. Anyone else see anything like this?

Thanks Skipgear...

"Something you can do in the meantime is run the loco. Because of the blackening on the frame and the drivers, electrical contact is compromised from the get go. The best thing for the loco is to set it on a loop of track and let it run for a couple hours. This will polish the axle bearing surface on the frame and the drivers, allow the drivers to wear into the bearing pockets a little bit and equalize themselves and generally let the locomotive drive train free up considerably."

My Northern 4-8-4 is running really nicely now..thanks for the advice and info. One final question: the only time it falters now is on the "turnouts" or "points" as we Brits call them. I have confirmed using a meter that the "frog" is powered on all 3 turnouts on my main line lay out. Any ideas why it would still hesitate when going over them?

Thanks...

Thanks "Skipgear"...you are right, I had posted the wrong diagram. Thanks for the correct one.

"pickup is accomplished through the split frame and axle bearings of the wheels which are electrically active"

Thanks for also answering the question. So power is picked up through the axles directly contacting the body of the loco right?
I do let this one run for a long time and it does improve after a while. That would explain it, polishing the contact surfaces.

I have read a lot on line about this loco and how to improve smooth running. Mine is part# 58152 with running # 3783. It's not bad and I have taken it apart and lubricated/cleaned it carefully. It does however still jerk and stall now and then. I am not sure if this is caused by eletrical cut out or by the conn rods jamming (have been lubed several times). I still have not found out exactly where the eletrical conacts or "feelers" are that pick up power from the wheels, even with the diagram (does not have part #'s described). Mine does not have any pickup on the front pony truck or tender.

http://www.bachmanntrains.com/home-usa/dwg/dwgs/N821X-IS001.PDF

Any help/words of wisdom much appreciated. Can anyone put a part # to the electrical pickups in the above diagram?

Thanks..