Yellow = CAT?
Prob the color of the manufacturer or company that owns it.
For example there is a certain large company in KC who's tower cranes are all blue. Another who's are all white. Both being their company colors, respectively.
man, cns casey (brain surgeon) dropping some massive tower crane knowledge on your n00b domes.
of course, dunn's cranes were made in spain by linden comansa (this is obvious not only b/c of the royal blue color but also because of their flat top design (no wires supporting the jib)). dunn has the largest fleet of tower cranes in the entire country. snack on that little nugget for a while kids.
i've got a pair of blue tower cranes on my block. lemme tell you, it's rough ridin' fantastic waking up to those beauts every morning.
i'll be back later after your head is done exploding, etc. peace. go cats.