Large Scale Central

Bachmann Trolley rebuild

Problem Solving
#1

My Bachmann two axle trolley stopped running. The motor didn’t stop, but the trolley did. It sounded like a broken gear, so I took the motor block out and looked at them. While worn, they didn’t seem cracked or broken. The idler gears were tight on their axles. I removed the motor, got the gunky white grease off the worms, put a drop or two of light oil on the armature shaft and turned power on. It ran with little noise or vibration. Then I removed the wheels and axle sets and inspected them. No breaks or cracks in the gear, but it slipped on the axle, making the same snapping sound the truck did originally. So I cleaned the axle as well as I could and reg=gauged the wheels, which were about one eighth inch too tight.

For the time being, I decided to make a trailer out of the car, so i took out the idlers and the motor. Before I put the motor block back together, though. I realized that with the motor out, I couldn’t power the lights. I tried to put brass jumpers between the press metal contacts between the power in from the track, and the power out to the lights. For some reason, the contacts against the wheels are NOT picking up power from the wheels. I cleaned them but to no avail. They did work intermittently before the gears started slipping.

Any ideas what to do to fix electron flow?

#2

Update: I cleaned the axles and found three of four gears cracked on two cars! On the trailer car, I’ve now got electrical contact from the wheels to the lights. I removed one axle gear from the other trolley and it appears that one gear will pull the trolley. I’ve decided to get six new gears and just replace them all. Now I’ve got 1.5 trolleys! Now I’m removing the hook couplers and replacing them with 3D printed draw bars.

Is this the enjoyment with everlasting challenge part?

#3

Great to hear your got your Trolleys going on the tracks again.

I got two of them with both motors now dead. I seen Bachmann now has replacement motor blocks but with out the old sliders on them Our ran… when running had sliders beside the wheel wipers on them and ran great and no problems as the ones with no wipers on them for extra pick ups. Cast wheels are bad and we had to do a lot of cleaning on them.

Now saving up money for USA motor block with the slider on them to re- modify our Trolleys for better long lasting running. They should work better on our back and forth trolley line.

#4

None of my trolley’s motor blocks have sliders. All contact is through the tiny brushes rubbing the back of the wheel.

There’s a guy either here or on MLS who makes replacement gears for these guys. I’m thinking of buying six and replacing all of them on my thee trolleys. Might even do a clinic on repairing these trolleys. They are fun to run, and the two with Santa and an elf are appropriate this time of year!

But I will need to find a simple and inexpensive way to remove a wheel and then re-gauge them.

#5

I removed the Bachmann motor block and installed a USA Trains block. Of course this was 5 years ago when the motor blocks were $35.00.

These trolleys have never had another issue with these motors installed.

#6

Dan Pierce said:

I removed the Bachmann motor block and installed a USA Trains block. Of course this was 5 years ago when the motor blocks were $35.00.

These trolleys have never had another issue with these motors installed.

…

Question, Dan. P.

Did your get the USA motor blocks with the slider on them? That what I need with all of pine and dust gunk that get on the tracks out here. Ya the USA motor block sure went up in price.

The old Bachmann Trolley blocks use to have slider beside the wheel wipers on them.

#7

I want to remove this. TOO MANY SPELLING ERRORS.

#8

Latest update on my Bachmann trolleys. I 3D printed new axle gears. I’ve installed them on the axles (see picture, enough for one car. Will do the other cars as needed. Nice snug fit of gear on axle. I’ll try to put the car together before Saturday’s club meeting, so I can run i t on meeting members’ layout!

#9

That looks great Dick!

#10

Finished one trolley this afternoon, and put it on rollers to try it out. It ran for about five hours straight. Seemed to run fine – at least no smoke!

#11

Hey Dick,

Are you actually printing these yourself or are you having them printed? I am glad they are working for you. I hope I have the same success. I mean this could really bring life back to models that otherwise are written off.

#12

Yes, and you used pla instead of abs? I’m a bit suspicious of how long they will last… I did some reading, PLA definitely not recommended in hot climates.

Can you get them printed in nylon?

Greg

#13

Greg,

I am working with the guy who printed my drivers. Dick and he both acknowledge that PLA is not the best plastic for this. Peter does not like ABS for this because in the past he has had issue with delamination and he thinks the teeth will break. Nylon is certainly an option and is one we are looking at. He has another product (he hasn’t said what) that he wants to try. He is going to do some test prints in a few materials. then when he comes up with a good product he will send them to me.

Another option we are working on right now is I will have Peter print gears that are 5-10% larger than what I need and then John C is going to experiment with using those to make molds for lost wax casting brass or bronzes ones.

I think being able to easily design gears in TinkerCAD as Dick has shown us then having them printed is a great option for this cracked gear problem. It allows us to make one off gears easily and inexpensively. If John can cast them then all the better.

Its going to be a team effort but I am excited about the prospects and thank Dick for breaking the ground for us.

#14

I printed them on the Sacto Library’s Makerbot printers using PLA. Due to the potential for fumes in a small un-ventilated room, the library does not print in ABS. One of the men there has an ABS capable printer at home, and will make a gear for me. If you have a resin 3D printer, you could print them out of resin. I plan to rebuild one of the motorblocks with one ABS and one PLA gear to see how each holds up against the other. I don’t recommend nylon, as that looks like what the broken gear was made from. If it were possible to print in Delrin, that might be better as it is natually slippery.

So far, my experience with PLA has been 100% counter to “general opinion.” It is very hard (try sanding it), seems resistant to UV (which really won’t matter since the gear is far from sunlight). When it fractures, it’s commonly along the laminate lines.

#15

Dick Friedman said:

When it fractures, it’s commonly along the laminate lines.

This is what Peter is worried about in ABS. He has problems with it. I wonder if resin is what he wants to experiment with.

#16

Devon Sinsley said:

-snip- Another option we are working on right now is I will have Peter print gears that are 5-10% larger than what I need and then John C is going to experiment with using those to make molds for lost wax casting brass or bronzes ones. -snip-

Been doing homework and brass is winning as our alloy of choice and because the price of prints is coming down, I want to burn them out instead of adding 2-3 chances to loose detail by molding them first. I expect the shrink rate to be 3-4%…

Bronze gears would tend to eat the other ones while brass is preferred.

Bronze rims would be harder, but track is too expensive, so perhaps it’s better to sacrifice replaceable rims than rails. Thoughts?

John

#17

Dick, nylon has been used for years successfully. The reason the nylon gear broke was bad engineering, made too small so the press fit created excessive stress. (also cannot speak to the quality of nylon used in this case)

Printing nylon is indeed more difficult, but done right, all the research I have done says it is superior to PLA and ABS for gears.

Greg

Dick Friedman said:

I printed them on the Sacto Library’s Makerbot printers using PLA. Due to the potential for fumes in a small un-ventilated room, the library does not print in ABS. One of the men there has an ABS capable printer at home, and will make a gear for me. If you have a resin 3D printer, you could print them out of resin. I plan to rebuild one of the motorblocks with one ABS and one PLA gear to see how each holds up against the other. I don’t recommend nylon, as that looks like what the broken gear was made from. If it were possible to print in Delrin, that might be better as it is natually slippery.

So far, my experience with PLA has been 100% counter to “general opinion.” It is very hard (try sanding it), seems resistant to UV (which really won’t matter since the gear is far from sunlight). When it fractures, it’s commonly along the laminate lines.

#18

You are probably right, Greg, about the nylon. But I don’t know whether to be sure the hole is a bit larger than the axle (6.5mm works great on my 6mm axles), or the gear should be thicker. If the gear was as thick as the gear and shoulder, would that make it better you think? It would be easy enough with Tinkercad to make the gear thicker, even with PLA or ABS.

Today at Club meeting I ran one of my trolleys (the one whose motor is NOT overheating) for about five or ten minutes. It ran well, little stuttering, on a track which had been running a short train only moments before. That and yesterday’s ten minute run seems to prove the reliability of PLA in the short run. I’m going out to the workshop to put it on the rollers and run it some more.

#19

Still not sure what Peter printed my gears in. I will ask. But he got four of them done off my drawing. He said they printed very well and mesh well with one another. Hopefully they mesh well with the mated gear. I can’t wait for him to send it to me. He said the plastic is similar to ABS without the delamination problem.

Per John’s, request if the gear is acceptable, I will have Peter print a bunch at 3% and 6% larger and send them to John to play with. If John can get a good gear in brass then the printed materiel will be a mute point. We can print them in what ever materiel makes the best blank. Brass gears would always be preferable in my opinion.

Of course having a brass axle gear and plastic drive gear (or what ever its called) means eventually we will wear out the drive gear. Ultimatly it would be best to design and print then cast the set.

In all of this experimentation and conversation is the fact that it is now feasible to fix those split gear issues.

#20

Only one more problem with my Bachmann Trolley rebuild. I’ve replaced four gears on two of the trolleys. Today i ran the first rebuild for about two hours and it ran fine. The second got gears and I put it on my rollers. After just a few minutes, I smelled the motor overheating, so I took the trolley apart, removed the motor and set it aside quickly as it was too hot to handle.

So the new question is, why does a motor overheat and how do I fix it. I lubed the shaft, but that doesn’t seem to help, it just takes a little longer to overheat.