Traction

[JimmyB]

This morning damp rails etc caused some traction issues with my Otto on some of the gradients when pulling a load. As most of you will know this loco does not come with a traction tyre (pros and cons of traction tyres). However as an 0 Gauge modeller, most locos use to be kits, and additional weight was recommended to get good traction. So having some lead shot I added (in a bag externally) 400 grams of extra weight.
So the discussion is, is there an optimum weight for various loco configurations, is using additional weight for traction a good thing, and what are the down side of the extra weight!!
P.S. can we wait ten post untill we drift

 

[PhilP]

The 'Otto' is a very small engine, and quite a lightweight..
I personally would not add more than 25-33% of original weight to a loco. How many (of what) did your train consist of?

Trying to drag stuff uphill, especially if curves are also involved, is a little unfair on a small engine.

 

[idlemarvel]

All good questions. I don't have any definitive answers but here are a few observations.
With real railways weight is not a problem, rather trying to spread it across more wheels. Their answer is to increase the friction with sand etc, the model form of that would be traction tyres/tires.
Increasing weight in the loco reduces the weight it can pull.
The weight you add will need to vary with load pulled.
So no easy answers.

 

[Zerogee]

How did your experiment with 400g extra weight work out, Jimmy?

As far as I'm aware, the only downside of adding too much weight is the potential for increased wear on the motor and gearbox - and given that the Otto mechanisms and motors are not QUITE as sturdy as the "standard" LGB power unit with a Buhler motor (though they are still pretty good), this could be a problem some way down the line (so to speak).

Jon.

 

[Rhinochugger]

Yep, some people worry about gearbox strain, but if the wheels cans till slip, then you haven't reached that point. In any case, more damage is done to a gearbox through stop / start (including dodgy track continuity) than overloading.

Personally, I'd only start to worry about the wear on the axle bearings, and you're going to have to run trains in extreme 'Duffy' mode to get to that point.

If your track starts to look like this, then it's time to start worrying

 

[JimmyB]

PhilP I had three two axle coaches, fine on the flat, just slips on the gradient, however the coaches are not as free-running as they could be, I need some metal wheels for them and at £20.00 plus per coach not cheap. The loco (without extra weight) is 1.725 kg, so the extra 0.4 kg is less than 25%, and it cuts down slip, but not 100% possibly around 90%, so the wheels can still slip if needed.

 

[Greg Elmassian]

One rule of thumb I have operated by, is actually looking at the scale weight of the loco.

divide the prototype weight by the cube of the scale. You would be surprised how well this works... I use it for rolling stock also, but in the unloaded state.

Greg

 

[korm kormsen]

my otto is weighted up to 2.3 kilograms. the stainzes and motorized tenders between 2.4 and 2.5.
this is the result of a lot of trial and error tests.

the trains run with about 12 Volts up a 6% (1 in 16.66) grade with 6 standard one-foot LGB-cars. (12 axles total) plastic wheels.

so, if your grade is similar to mine, i would say you can't expect more from your otto.

edit: my slip test: under power i hold the loco by the rear coupler, if it doesn't slip, i take away some weight.

 

[PhilP]

edit: my slip test: under power i hold the loco by the rear coupler, if it doesn't slip, i take away some weight.

This is the most important part..
The loco MUST still slip.. If it doesn't, there is a chance of stripped-gears, or burnt-out motor(s) / electronics..

 

[JimmyB]

Korm, great piece of advice, it would seem your Otto is slightly heavery (2.3 kg) than my AUM at 2.125 kg, but it would seem I am not far out. I will confirm the slip, and then look at permanently adding the weight. It would seem my Bachmann Mogul will be next

 

[Paul M]

Yep, some people worry about gearbox strain, but if the wheels cans till slip, then you haven't reached that point. In any case, more damage is done to a gearbox through stop / start (including dodgy track continuity) than overloading.

Personally, I'd only start to worry about the wear on the axle bearings, and you're going to have to run trains in extreme 'Duffy' mode to get to that point.

If your track starts to look like this, then it's time to start worrying

View attachment 243837

What on earth?

 

[Zerogee]

What on earth?

I've seen that photo several times before, and assuming it is genuine (and if it's not, then it's very well done!) then I can't really imagine the circumstances under which it could have happened.... obviously an 0-6-0 of some kind must have sat there for hours, if not days, constantly spinning its wheels with no-one paying it any attention.....

In a less-impressive way in our scale, something similar can indeed happen of you leave an LGB track cleaning loco unattended and it somehow gets stuck in one spot with the cleaning-wheel motor still spinning!

Jon.

 

[Paul M]

I've seen that photo several times before, and assuming it is genuine (and if it's not, then it's very well done!) then I can't really imagine the circumstances under which it could have happened.... obviously an 0-6-0 of some kind must have sat there for hours, if not days, constantly spinning its wheels with no-one paying it any attention.....

In a less-impressive way in our scale, something similar can indeed happen of you leave an LGB track cleaning loco unattended and it somehow gets stuck in one spot with the cleaning-wheel motor still spinning!

Jon.

Perhaps it was that then!

 

[Neil Robinson]

I'd also seen that image before. This is another view of, I think, the same site. This one would have been caused by a Co-Co loco.

https://imgur.com/XqUDb

 

[Zerogee]

I'd also seen that image before. This is another view of, I think, the same site. This one would have been caused by a Co-Co loco.

https://imgur.com/XqUDb

Ah yes, in that shot you can clearly see the second set of gouges from the other power bogie!
Still wondering how it could have occurred, surely even if a loco had become completely stuck for some reason they wouldn't have kept trying to free it for so long rather than bringing up a rescue engine...?

Jon.

 

[PhilP]

Ah, well/.. There's the rub! - Literally!
As with modern tractors (agricultural) large engines like the Yeoman, can 'dial-in' slip, so the wheels can actually 'spin' in a controlled manner.
I asked about these pictures, and was told that the drivers (or one, at least) did not realise what this meant. An aggregate train had a brake problem, and the loco was left running whilst driver walked back to check. - As told to me..

I am told that a Yeoman, at night, with sanders, and 5% slip coming out of the quarry is quite impressive.

Of course, this could have been a wind-up, but the source was credible.

 

[Zerogee]

Ah, well/.. There's the rub! - Literally!
As with modern tractors (agricultural) large engines like the Yeoman, can 'dial-in' slip, so the wheels can actually 'spin' in a controlled manner.
I asked about these pictures, and was told that the drivers (or one, at least) did not realise what this meant. An aggregate train had a brake problem, and the loco was left running whilst driver walked back to check. - As told to me..

I am told that a Yeoman, at night, with sanders, and 5% slip coming out of the quarry is quite impressive.

Of course, this could have been a wind-up, but the source was credible.

Sounds worryingly similar to the plot of "Unstoppable", to me.... mind you, that movie is based on real (if not quite so spectacular) events......

Jon.

 

[JimmyB]

my otto is weighted up to 2.3 kilograms.

Korm, having stripped down my Otto I am having difficulty in finding space for extra weight, what did you use for weight and where did to put it.

 

[Rhinochugger]

What on earth?

I've seen that photo several times before, and assuming it is genuine (and if it's not, then it's very well done!) then I can't really imagine the circumstances under which it could have happened.... obviously an 0-6-0 of some kind must have sat there for hours, if not days, constantly spinning its wheels with no-one paying it any attention.....

In a less-impressive way in our scale, something similar can indeed happen of you leave an LGB track cleaning loco unattended and it somehow gets stuck in one spot with the cleaning-wheel motor still spinning!

Jon.

I think I've seen a video somewhere - assume it's a helper loco slightly out of sync with a long, heavy train trying to get started

 

[Zerogee]

Korm, having stripped down my Otto I am having difficulty in finding space for extra weight, what did you use for weight and where did to put it.

Not from personal experience, never having had an Otto to bits, but I'd think that Tyre Balance Weights might work - the self-adhesive ones, just stick 'em wherever you can - inside water tanks, cab floor, etc..... just try to keep the extra weight well distributed fore-and-aft to avoid unbalancing the loco if you can.

Jon.