Rolling stock weight
- Thread starter mickoo
- Start date
Heather Kay
Western Thunderer
I toyed with the idea of scaling the real weight down to 1/43rd. I can't recall the maths I used now. The idea was to stop vehicles clattering about when moving, and to lend some mass so they moved more smoothly.
It didn't really work, and also relied on everything having the same kind of suspension system.
Anyway, I reckon your 600g is a little light. I'd consider around 800g as a start.
It didn't really work, and also relied on everything having the same kind of suspension system.
Anyway, I reckon your 600g is a little light. I'd consider around 800g as a start.
Steph Dale
Western Thunderer
Mick,
The only place you'll find a formula for rolling stock weight is in the NMRA RP20.1. For 0-gauge the formula (IIRC) is:
1oz constant + 1oz per axle + 1oz per inch length. For locos I then go somewhat heavier.
The 'scale weight' approach is interesting, you just need to remember that weight is a funtion of volume, so the prototypical weight will need dividing by 43^3.
Steph
The only place you'll find a formula for rolling stock weight is in the NMRA RP20.1. For 0-gauge the formula (IIRC) is:
1oz constant + 1oz per axle + 1oz per inch length. For locos I then go somewhat heavier.
The 'scale weight' approach is interesting, you just need to remember that weight is a funtion of volume, so the prototypical weight will need dividing by 43^3.
Steph
mickoo
Western Thunderer
Graham, no idea on motor or gearbox weight, not got that far yet but if you can weigh yours it'd help tune the CSB settings.
Heather, likewise, I'm keen to avoid the train clattering over point work in a wooden fashion, a decent weight coupled with a reasonable deflection (currently working on 1mm) should allow the loco to ride over track work in a more visually pleasing way.
Steph, if I read the first formula then I'm looking at 84oz which is 2.3kg, might have to rethink my baseboard construction at those rates, especially the Princess Royal loco LOL.
Heather, likewise, I'm keen to avoid the train clattering over point work in a wooden fashion, a decent weight coupled with a reasonable deflection (currently working on 1mm) should allow the loco to ride over track work in a more visually pleasing way.
Steph, if I read the first formula then I'm looking at 84oz which is 2.3kg, might have to rethink my baseboard construction at those rates, especially the Princess Royal loco LOL.
Heather Kay
Western Thunderer
Dog Star
Western Thunderer
So a JLTRT TTA model comes out at around 600 grammes, which in prototype terms is in excess of 100 metric tons.
Heather Kay
Western Thunderer
A Gronk in working order is about 50 tons. That would work out about 6kgs. 
I think, in the end, my experiments with "scale weight" ended up trying to ensure a 10 ton wagon weighed something in proportion to a 100 ton loco.
Please note: I failed maths at school. I can't add up to save my life. Any calculations shown here are probably miles out.
I think, in the end, my experiments with "scale weight" ended up trying to ensure a 10 ton wagon weighed something in proportion to a 100 ton loco.
Please note: I failed maths at school. I can't add up to save my life. Any calculations shown here are probably miles out.
Osgood
Western Thunderer
http://en.wikipedia.org/wiki/Square-cube_law 
Although what happens to density as an object is reduced is probably another kettle of fish altogether.
And something like gravel being loaded into a wagon never looks right - far too fast!
Although what happens to density as an object is reduced is probably another kettle of fish altogether.
And something like gravel being loaded into a wagon never looks right - far too fast!
daifly
Western Thunderer
Actually, if my calculations are correct, the gronk scales as 629gms.A Gronk in working order is about 50 tons. That would work out about 6kgs.
I think, in the end, my experiments with "scale weight" ended up trying to ensure a 10 ton wagon weighed something in proportion to a 100 ton loco.
An older wagon loaded to 10T would typically gross at c16T which, in turn, scales to 200gms.
Steph Dale
Western Thunderer
Mick,
How the heck did you get the 08 to 84oz...??!?
1oz constant +
3oz for the axle count
10oz (say) for a 10" long loco
=
14oz. So under a pound. You could double it as it's a loco, whereupon you'd be close to 800g...
Steph
How the heck did you get the 08 to 84oz...??!?
1oz constant +
3oz for the axle count
10oz (say) for a 10" long loco
=
14oz. So under a pound. You could double it as it's a loco, whereupon you'd be close to 800g...
Steph
Dog Star
Western Thunderer
The recommended ABC motor and gearbox for a Gronk is 80gms.
regards, Graham
Dog Star
Western Thunderer
How would you know that I made a mistake in my conversion between historical and modern measurements... never mind that, I was working on around 12 Tons for the empty weight of a TTA.
Osgood
Western Thunderer
Heather Kay
Western Thunderer
String. It can be knotted or not, but I find string (as well as London buses and Wales) to be a useful measurement tool.
mickoo
Western Thunderer
Steph,
Misread oz per loco inch, thought it was 10oz per inch!
So generally speaking we're looking at 600-800g
mickoo
Western Thunderer
Much obliged
Heather Kay
Western Thunderer
No, you misunderstand. Wales is used as a measure of size, so "As long as this piece of string", "As tall as three London buses", or "About the half the size of Wales". Leeks and daffodils are more about measuring the length of a poem, aren't they? Or is that leeks and manifolds?
*desperately trying to steer the conversation back to railways somehow*