I have just been looking at the details on a first version CM800 (3000) from 1953, and they really are impressive!
So many tubes and pipes are featured on the boiler! Valves whistle, etc. It is no wonder that Märklin was so successful.

And they produced this shell without any computers too! Plastic injection moulding allowed levels of detail that were simply impossible with metal.

The whole model is just an incredible example of post war engineering. The design well deserves to be the most produced model train ever. I just noticed that the Märklin web site says it is no longer in production, which does surprise me. I know they have a newer model of the BR 89, but I always assumed they would never stop production of the classic 3000, at least to be able to maintain the production record.

As a kid I had a 3029 and both my brothers had the 3000. I was so envious, their models had nice complex valve gear, and lights too! I was in my late 20s before I managed to own a steamer with nice valve gear, but now I have a fleet of 3000s plus many others with exquisite details.

Anyone know which Märklin loco was the first to use a plastic shell?

Dale,

My best guess is that the first locos to use a plastic shell were the CM800 and the CE800 (E63 greenie) both from 1953. M used plastic before that with some of their freight cars (1951), but I can't find any plastic shell locomotive until 1953. The two locomotives that I got from my dad when I was young were purchased in 1954 - the previously mentioned CM800 and my favorite - DA800. Curiously this first version of the DA800 was unveiled that same year and the shell was made of plastic. I still own both and they run just as well as they did 67 years ago.

Kurt

3000 and 3029 have sentimental value for me too, and yes you're right the detail on 3000 (and it's prior numbers) is really very good. I tend to like the older models that have a really good amount of detail combined with a sort of indestructibleness that enabled them to survive a hard life in the engineering hands of a child (ramming speed, numerous head-on collisions and falls to the floor, along with being drowned in oil) and still work perfectly today when I'm in my late 40s. That is the 3000 in a nutshell.