A Marklin HO was used to get all the dimensions of the 191 and massaged a bit for the Z Crocodile. The owner was kind enough to lend me their loco. I took plenty of photos and drew up all the dimensions.

The Marklin Z Crocodile chassis was used, but it was a bit difficult to reconfigure the wheel arrangement due to the couplings obviously needed, so I decided to leave the wheels as is. If all else failed I could revert the loco to the Crocodile. These are expensive locomotives.

The brass body was started as a far longer block with clamping holes at both ends in top and side directions so it could be rotated 90° in the mill. Unfortunately I did not take a photo at this stage. The mill was a large prehistoric clunky old beast with a few mm play. Quite frankly not the sort of machinery one would use when tolerances of a 0.1mm are required. But it does show what you can do with very worn out equipment.

Once it was machined up. I cut it into the three sections, then cut off the two clamping ends. Soldered in window frames etc. Still have to add a few bit and pieces, then prime and top coat.

I built this a few decades ago, technology options has completely changed. These days I would look at 3d printing, even titanium printing to increase mass over plastic. Titanium is not as heavy as brass but a lot better than plastic. In brass the gross weight is currently 88 grams, so pretty useful. Maybe 90 grams once completed.

To date I still haven't got around to finishing off this loco, don't retire as you won't have time for anything! Actually I quite like the brass half finished look, but I think I will finish it off eventually.

Anyway, hopefully food for thought for 3d printing in the 21st century or automated milling. The only difficult part in this whole process is measuring and documentation. Getting dimensions into a 3d file is easy once you have the basic drawings. Once that is done you can produce multiple copies.

WOW Toos, you really build very nice stuff!