Laaers German Vehicle Transport: Color Cars?

Checking photos I have taken on TSW4... I noticed this one:


There as you can see the Laaers freight wagons, it has the cars on different color.
But the one you can use in the sim, are all white cars.

So it is not possible those colorful ones, be used on the sim?
Which is the cause?

 

you can use them in game i think i only ever see them on bremen oldenburg though