LGB 23701, Jerky start and running

[geofc]

I own an LGB 0-6-2 model No. 23701.
Recently experiencing very jerky starts from stationary.
Once it is given an encouraging push, it finally takes off and when it is 'warmed up' it settles to an acceptable smoothness.
When it is slowed down then comes to a stop, the issue is again apparent.
Re-starting is again very jerky.
Sometimes it just sits still as the throttle is increased and the motor 'hum' is heard but no movement.
Have checked the worm and gears for debris, lubricated the bearings and gears, electrical continuity is checked.
My gut feeling is that the motor is failing or has lost magnetism.
Anyone else experienced this issue?
What are some likely causes?

 

[dunnyrail]

First step in to ensure that the wheels are properly quartered as one of the gears can get out of step. Best way to check if this is ok is to lay Loco on it’s side in a pice of soft cloth then see if the axles are matching their angle. If cog out on the gears can just be not noticed that is all it can take to give lumpy slow performance.

 

[geofc]

Thank you for that idea, will do.
Have just opened the motor block and lifted the geared axles clear of the motor shaft worm gears. The motor runs freely on it's own. Starts smoothly then can be accelerated to maximum without any jerkiness.
Now I will check the quartering before I sit the axles back on the worm gears. The side connecting rods all seem to have plenty of slack available and there is no evidence of linkages binding or locking anywhere.
Consequently I reckon your suggestion is the likely cause. To test that, I am going to deliberately shift the gear wheel on one axle one cog to the LEFT off top dead centre and run the motor to try that.
Then I will try that same gear wheel axle one cog RIGHT off top dead centre and run that to see if it helps or hinders.
That little test may reveal more data for consideration.
Once again, thank you.

www.trainweb.org/btr/

- this video shows this Locomotive operating normally prior to this issue developing.

 

[JimmyB]

First step in to ensure that the wheels are properly quartered as one of the gears can get out of step. Best way to check if this is ok is to lay Loco on it’s side in a pice of soft cloth then see if the axles are matching their angle. 01480 XXXXXX cog out on the gears can just be not if=ced that is all it can take to give lumpy slow performance.

Jon, a cut and paste error, maybe!

 

[dunnyrail]

Jon, a cut and paste error, maybe!

Thanks Jimmy, a text replacement thing me thinks. Original post revised.

 

[a98087]

Had one that did similar, it was an older model, and the motor had removable brushes
It took me a while to find but there was a tiny bit of dirt between the brush and holder, that prevented it from sliding freely.

so ensure the motor brushes can slide up and down freely, and make a good contact on the armature.

On the same loco, it also had bent valve gear, and would sometimes lock up, and sit there with the motor buzzing.

Both those issues were hard to find due to their intermittent nature.

luckily these locos aren’t to hard to dismantle.

Hope my ramblings make sense

Dan

 

[geofc]

Had one that did similar, it was an older model, and the motor had removable brushes
It took me a while to find but there was a tiny bit of dirt between the brush and holder, that prevented it from sliding freely.

so ensure the motor brushes can slide up and down freely, and make a good contact on the armature.

On the same loco, it also had bent valve gear, and would sometimes lock up, and sit there with the motor buzzing.

Both those issues were hard to find due to their intermittent nature.

luckily these locos aren’t to hard to dismantle.

Hope my ramblings make sense

Dan

It appears that the gear grease may be separating into two components, an oiliness that has spread via low surface tension and gluggy grease globs that are sitting on the gearbox walls as if they have been flung off the gears.
I may degrease the whole motor block, the motor may have been contaminated by the low viscosity oily film that has spread. Then I will undertake the checks you have suggested. I have now checked the quartering and all is OK there.
Thanks for your contribution. Geof

 

[Paul M]

It appears that the gear grease may be separating into two components, an oiliness that has spread via low surface tension and gluggy grease globs that are sitting on the gearbox walls as if they have been flung off the gears.
I may degrease the whole motor block, the motor may have been contaminated by the low viscosity oily film that has spread. Then I will undertake the checks you have suggested. I have now checked the quartering and all is OK there.
Thanks for your contribution. Geof

Sounds like someone has been making free with the WD40

 

[PhilP]

Sounds like someone has been making free with the WD40

Not necessarily...

I often find very old grease has gone a dark orange colour, and quite stiff and waxy..
The 'oil component' has separated out, and quite often contaminated the motor.

The 'tell-tale' is that there is 'oil' around the edge of the bottom plate of the motor block.

PhilP

 

[dunnyrail]

Sounds like someone has been making free with the WD40

Ah yes WD40, the amount of people you see at shows (generally poor build train set type layouts) spraying the undersides of locomotives with that stuff to sort out some kind of recalcitrant loco. A good clean, proper lube and well laid track would solve many of the issues.

As for shows, I thought that I was missing them but thinking through the WD40 issues and much of the way show layouts are run just made me remember I leave most of them feeling disenchanted by much of the dross and playing trains seen.

 

[Gavin Sowry]

Ah yes WD40, the amount of people you see at shows (generally poor build train set type layouts) spraying the undersides of locomotives with that stuff to sort out some kind of recalcitrant loco. A good clean, proper lube and well laid track would solve many of the issues.

As for shows, I thought that I was missing them but thinking through the WD40 issues and much of the way show layouts are run just made me remember I leave most of them feeling disenchanted by much of the dross and playing trains seen.

Took along my 3 in 1 oil to the Kapiti Show for track cleaning and lubrication, as I do. It never left the toolbox..... therein lays the lesson about preshow preparation.

 

[Paul M]

Ah yes WD40, the amount of people you see at shows (generally poor build train set type layouts) spraying the undersides of locomotives with that stuff to sort out some kind of recalcitrant loco. A good clean, proper lube and well laid track would solve many of the issues.

As for shows, I thought that I was missing them but thinking through the WD40 issues and much of the way show layouts are run just made me remember I leave most of them feeling disenchanted by much of the dross and playing trains seen.

There's always one or two not very good (shall we say for politeness sake) layouts, but there's usually more than enough good ones to make up for the bad ones. Everyone different tastes, so it must be hard to cater for all

 

[geofc]

Update on my LGB 23701 which had Jerky starting issue.

After dismantling the motor block, cleaning away emulsified grease, cleaning the motor, checking wiring, lightly lubricating then re-assembling the problem still remained when I did a test run.
My test track is set at eye level, I started yet another test run and happened to notice a damaged valve gear linkage.
The main crank off the centre drive wheel pinion had split open and was making the drive wheels "limp" (the jerkiness).
Wish I had seen that before I did all the other dismantling and reassembly.

Tried to glue the segments back together and yet the material appears to be a combination plastic with metallic particles that inhibited a good bond.
The interfaces were about 2.0mm x 0.75mm, the glued repair was not "loadworthy" in my view.
I chose to fashion a replacement part from styrene as I could not imagine that a replacement part could be purchased.
A test run with the said crank removed and the linkage wired clear for the test, revealed that the Loco was thus capable of free running.
Reassembling with this makeshift repair has seen the Loco running freely again.
While the Loco was lying on the bench in pieces, I took the opportunity to tidy up the internal R/C, Rx, LiPo, ESC, Direction DPDT servo actuated switch, MyLocoSound card, LEDs and wiring.
The result of this major overhaul was a good thing in the end.

All is well with the world again!

 

[Rhinochugger]

Something at the back of my mind suggests that this was the Achilles' heel of these locos. When people tried to argue the might and perfection of LGB, this was always one of the chinks in the armour.

 

[stevedenver]

yes, these 2070 series with the plastic rods do have rather delicate rods etc.
while i have repaired one, successfully, i strongly suggest to bite the bullet and buy complete replacement sets. they are pricey. But, as mentioned, gluing for the most part will fail eventually.