John Duffy
Western Thunderer
Being even more specific, I too feel it is too dirty, but in a specific way. It looks like it was been 'weathered' only by the cement. I suspect that the real thing got as dirty as many other wagons but not just from the load it was carrying. Perhaps more road dirt on the under frame and a lighter washing on the body.I also think it's rather too dirty, the cement would be in sacks. If they leaked that much powder the company would do something about it. I would imagine that under the doors you may get spillage, but the rest of the van would be more road dirt and soot.
One other factor to consider is that the company has gone to the trouble of using this van as an advert, they may well then have taken more care of it.
There are images here;
These tend to show fairly clean wagons with subtle weathering.
John