Trying to figure out the load capacity.
Looks like 29t gross. And 4.6t on the wheels empty, but it doesn’t say anything about weight on the legs or kingpin empty.
Ignore the white plate.
That is for use of workshops etc. It is about the Knorr-Bremse barking system fitted. It relates to the way the brakes are designed and set up. When it shows the bogie is 4600kg empty that is not (necessarily) the actual normal reaction on the bogie (the “weight”) but is the setting used at the factory. Different bodywork will alter the actual weight on the bogie.
The blue plate (Cartwright, the manufacturer`s plate) shows the max mass allowed on each axle (9,000kg) the bogie (18,000kg), the pin (11,000kg), and the max trailer mass (29,000kg).
Remember a 4 axle artic has a max of 36,000kg, and a 5 axle artic has a max of 40,000kg. (Dependent on other factors too)
Nowhere does it say the actual ULM or ULW (Unladen Weight) or any such.
So, insufficient info to say what the load capacity is.
(Haven`t you been doing this job 2 weeks or more? You should have passed your apprenticeship by now! 
)
Short answer: If you only want what it can carry then just take the trailer to a weighbridge and weigh the trailer without a unit.
Longer answer: But the result then really depends upon the unladen weight of the unit and if relevant, the unit’s taxation weight.
Longer answer still: The only way to find out all of what you may want to know is to take the empty trailer to a weighbridge and weigh it, the combination, the unit solo, (the unit axles solo), the unit coupled, (the unit axles coupled) and the trailer bogie coupled.
Forget that brake data plate, the unladen axle weight information on them is sometimes wrong, query with the manufacturer and they don’t seem to be bothered and say everything is OK so don’t worry about it. If the trailer has an ‘info centre’ then you may be able to verify that the brake data plate figure is correct.
Take it to a dynamic weighbridge is easiest - drive slowly across the sensors and you end up with the all the axles, unit, trailer and overall ULW. But, remember to take it full of full and any other kit that would normally be carried before any load is added
It can be done on a traditional plate weighbridge, but not as easy to do as much would depend on the towing unit
Simply dropping the trailer on the weighbridge won’t give the answer you want.
To stress that those are Max permitted weights.
As already said, dependent on vehicle tax and on correct wheels and tyres being fitted.
Those axles might be rated at 9,000kg, but check wheel and tyre ratings too.
Thanks all … Unfortunately there is no apprenticeship in place. Therefore 6 months of repetition, without training, means…I rely on you!
Anyway, I usually run so empty that it’s never an issue, but a colleague said he wouldn’t be able to take a load of 23t, but that the limit was 18t for these trailers would you be able (with your experience) to guess the ULM of the trailer?
The Actros is 7.5+7.5+11=24t
we run on 6 axles, volvo truck + SDC curtainsider @ 4.48m high with 27 ton of fertiliser on we gross 42 tons - so truck and trailer weigh about 16 ton i know the truck with fuel and my kit in it is just over 9.1 ton so the trailer is about 6 tons in weight . Your weights will differ - different unit , different trailer (looks like a 2 axle trailer ) so your weights will be different . the vaules stamped on the plates are the max design weights how the truck is taxed will determine what actual weights you can carry .
stu675:
would you be able (with your experience) to guess the ULM of the trailer?
6 metre skelly? 13.5m fridge with a tail-lift, pallet racks, and two spare wheels? Or summat in between?
The OP’s trailer seems to be a tandem. I can say that the 3 and 4 year old, Montracon, 4.5m high, pillarless, curtainsider tandems, with rear doors and running on BPW axles which we run, weigh around 6340kg but the OP’s Cartwright will be different.
If your mate is correct with 18t then the trailer weighs 11t so it may be a heavy fridge with tail lift, or something else. But we don’t know whether his is right or anything about the trailer or the ready to roll weight of the unit so what can be legally carried is not possible to say.
cav551:
The OP’s trailer seems to be a tandem. I can say that the 3 and 4 year old, Montracon, 4.5m high, pillarless, curtainsider tandems, with rear doors and running on BPW axles which we run, weigh around 6340kg but the OP’s Cartwright will be different.If your mate is correct with 18t then the trailer weighs 11t so it may be a heavy fridge with tail lift, or something else. But we don’t know whether his is right or anything about the trailer or the ready to roll weight of the unit so what can be legally carried is not possible to say.
Tandem or Twin axle?
2 x 9t is twin, 2x10t (spread-axle) is tandem?
Or not? Open to correction.
Won`t make any difference to ULW, but just being precise (pedantic!) in terminology.
stu675:
Thanks all … Unfortunately there is no apprenticeship in place. Therefore 6 months of repetition, without training, means…I rely on you!Anyway, I usually run so empty that it’s never an issue, but a colleague said he wouldn’t be able to take a load of 23t, but that the limit was 18t for these trailers would you be able (with your experience) to guess the ULM of the trailer?
The Actros is 7.5+7.5+11=24t
Guessing isn’t an option a certified weighbridge is the way to go for checking weights.
As a rough guess a 6 axle artic won’t take more than 25t payload even with a minimal weight flat trailer, probably less.
4 axle outfit will be lucky to take 15t these days with heavy units.
5 axle somewhere in between so 18t is as good a guess as any if it’s a 5 axle.
18t on a 4 axle doubtful.
Franglais:
stu675:
would you be able (with your experience) to guess the ULM of the trailer?6 metre skelly? 13.5m fridge with a tail-lift, pallet racks, and two spare wheels? Or summat in between?
A 4m high box, no fridge, no tail lift, no spare wheels.
beefy4605:
we run on 6 axles, volvo truck + SDC curtainsider @ 4.48m high with 27 ton of fertiliser on we gross 42 tons - so truck and trailer weigh about 16 ton i know the truck with fuel and my kit in it is just over 9.1 ton so the trailer is about 6 tons in weight . Your weights will differ - different unit , different trailer (looks like a 2 axle trailer ) so your weights will be different . the vaules stamped on the plates are the max design weights how the truck is taxed will determine what actual weights you can carry .
Thanks [emoji106] (although I’m sure you will be upset to have learnt that you’re running 2t overweight…CF).
So reasonable to guess my trailer is 6t or less and that 23t is possible. My colleague has possibly got the 18t from the gross weight limit on the trailer wheels.
Our 4.1m (Cartwright) tri-axle trailers tip the scales empty at 7480kg. They are not fridges, but they do have fridge style insulated bodies and roller shutter rear doors, all of which will push the ULW up a little.
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Carryfast:
stu675:
Thanks all … Unfortunately there is no apprenticeship in place. Therefore 6 months of repetition, without training, means…I rely on you!Anyway, I usually run so empty that it’s never an issue, but a colleague said he wouldn’t be able to take a load of 23t, but that the limit was 18t for these trailers would you be able (with your experience) to guess the ULM of the trailer?
The Actros is 7.5+7.5+11=24tGuessing isn’t an option a certified weighbridge is the way to go for checking weights.
As a rough guess a 6 axle artic won’t take more than 25t payload even with a minimal weight flat trailer, probably less.
4 axle outfit will be lucky to take 15t these days with heavy units.
5 axle somewhere in between so 18t is as good a guess as any if it’s a 5 axle.
18t on a 4 axle doubtful.
25 tonne payload on 6 axles 
where are you 1990 
,28/29 tonnes theses days .
Punchy Dan:
Carryfast:
stu675:
Thanks all … Unfortunately there is no apprenticeship in place. Therefore 6 months of repetition, without training, means…I rely on you!Anyway, I usually run so empty that it’s never an issue, but a colleague said he wouldn’t be able to take a load of 23t, but that the limit was 18t for these trailers would you be able (with your experience) to guess the ULM of the trailer?
The Actros is 7.5+7.5+11=24tGuessing isn’t an option a certified weighbridge is the way to go for checking weights.
As a rough guess a 6 axle artic won’t take more than 25t payload even with a minimal weight flat trailer, probably less.
4 axle outfit will be lucky to take 15t these days with heavy units.
5 axle somewhere in between so 18t is as good a guess as any if it’s a 5 axle.
18t on a 4 axle doubtful.25 tonne payload on 6 axles
Another gem of misinformation from the self proclaimed expert on everything. 
Punchy Dan:
Carryfast:
stu675:
Thanks all … Unfortunately there is no apprenticeship in place. Therefore 6 months of repetition, without training, means…I rely on you!Anyway, I usually run so empty that it’s never an issue, but a colleague said he wouldn’t be able to take a load of 23t, but that the limit was 18t for these trailers would you be able (with your experience) to guess the ULM of the trailer?
The Actros is 7.5+7.5+11=24tGuessing isn’t an option a certified weighbridge is the way to go for checking weights.
As a rough guess a 6 axle artic won’t take more than 25t payload even with a minimal weight flat trailer, probably less.
4 axle outfit will be lucky to take 15t these days with heavy units.
5 axle somewhere in between so 18t is as good a guess as any if it’s a 5 axle.
18t on a 4 axle doubtful.25 tonne payload on 6 axles
This^^^
Googlefast comes unstuck… (again) 
Roymondo:
Our 4.1m (Cartwright) tri-axle trailers tip the scales empty at 7480kg. They are not fridges, but they do have fridge style insulated bodies and roller shutter rear doors, all of which will push the ULW up a little.Sent from my VOG-L09 using Tapatalk
Call it 7t + Dan’s 28t payload = 35t.
The margins would be a bit iffy assuming around 10t for the unit.But I’m sure that I didn’t see or hear the 25t figure mentioned anywhere on Google.
“Guessing isn’t an option…”
Then immediately comes up with a guess that is several tonnes wide of the mark.
Still, at least CF’s guess was on the conservative side, which is by far the safer option. It would also mean he could reject any run he didn’t feel like doing, which would possibly suit his wider agenda of only being interested in “quality” Class 1 work…
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Carryfast:
Roymondo:
Our 4.1m (Cartwright) tri-axle trailers tip the scales empty at 7480kg. They are not fridges, but they do have fridge style insulated bodies and roller shutter rear doors, all of which will push the ULW up a little.Sent from my VOG-L09 using Tapatalk
Call it 7t + Dan’s 28t payload = 35t.
The margins would be a bit iffy assuming around 10t for the unit.But I’m sure that I didn’t see or hear the 25t figure mentioned anywhere on Google.
10 tonnes? Kerb weight for the Renault T480 midlift unit I normally use is 8.3 tonnes. Add 100kg for a driver and 25kg for the tat he carries around (full tank of fuel is included in the kerb weight).
I daresay a V8SuperDooperMega unit would be a bit heavier - but 10 tonnes?
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