LGB Feldbahn loc 20910 drive gear vs 25910

[Henri]

I bought a 'broken' 20910 with worn gears as the seller told me. For € 25,- I couldn't resits the try.

I still have to receive it (will be the week after this week probably) but I started looking for how the gears work on these. I've seen belt driven, presumably in a 20910.
The current 25910 is fully gear driven?

Are parts for the 20910 still available? Current owner didn't spent much time on research as he couldn't find the required parts easily.

Are 25910 parts usable?

 

[Zerogee]

All the old Feldbahn locos (steam and diesel) had the belt drive, but the latest versions have dispensed with the belt and replaced it with a lengthways propshaft using bevel gears on each end and on the axles.

I don't know if it is possible to put the new axles and driveshaft directly into an old-type belt drive gearbox - I think it may not be, because other things have changed too (including the actual motor type and shape). However I think that a complete new type gearbox/motor assembly will fit under the body of an old-type loco.

If it is the drive belt (or the gears that the belt runs on) that has failed on your little diesel, I do believe it is possible to simply remove the belt and make the loco rear-axle-drive-only, as the front axle will be turned by the side rods....?

Jon.

 

[Henri]

Oh boy, I think I'm lucky! A brand new gear on the front axle! Just swap & I'm all done!

 

[Zerogee]

Yep, that looks good, Henri!
When you swap the axles over, be very careful to check the "quartering" on the side rods - if you can, I would make a TDC (Top Dead Centre) mark on the wheels of both axles, to ensure that they are both correctly aligned when they go back in, otherwise you could have problems with the side rods binding up in certain positions. As long as you get the alignment right, you should be OK....

Good luck!

Jon.

 

[Fred2179G]

A brand new gear on the front axle! Just swap & I'm all done!

I am totally confused about why the LGB 20910 needed coupling rods AND a belt drive. I recently replaced both gears in one and the belt cog wasn't perfect, so I took the belt out. It runs fine with just the coupling rods.

I'm also confused why it has 2 lbs of lead weight! I suspect mine chewed up the gears trying to move that inertia!!

 

[Fred2179G]

A brand new gear on the front axle!

Well, in swapping out the gears, I may have bent an axle, as I cannot get the front wheels to run true. (This results in a waddling motion along the track!)

Anyone have a junk LGB 20910 or know where I can find a single axle?

 

[stevedenver]

I use the belts because the connecting rods really dont have the strength . I could be wrong, but id predict that eventually one of the holes will crack from stress and/or wear.

My thoughts come from lgb mallets, which have an idler middle axel, are ‘powered’/connected by the connecting rod, and simply roll along in synch with the 2 outer powered axels. This is typically fine, unless that idler axel actually carries a load, ie becomes the driver with the most adhesion. Then the strain can break the rod. How might i know this?

Try Only Trains.
If not, Train-Li.
If not champex linden.

Be mindful the you get the correctly sized boss for the drive rods. Eg, diesels only have the connecting rod, ie slim boss. Steam locos have a large boss on the rear axel to accommodate 2 rods, main and connecting, while front axel has slim boss.

 

[Fred2179G]

You bent the axel! Are you sure ?

(That turned up in the email - I assume you edited your post.)

I attacked it again yesterday, as it seems unlikely I'll find a new axle. I think it is wobbling less - when I get it on some powered track we will see.

Then the strain can break the rod.

I have to say I am appalled. Adequate strength coupling rods are mandatory. Anything less is bad engineering.

 

[stevedenver]

That’s ridiculous. These are plastic model trains.
The rods are cosmetic. Thats why theres a drive belt. That’s the engineering.

Youre right about the monster weight. Way too much for a single worm drive/axel. I too removed mine to avoid the wear.

Of course, you could fashion metal ones. And of course engineering to avoid the plastic bosses being worn down, like a brass sleeve….gets complicated huh?