The cab 2 windows and gitter (iron bars in front of the window) from a Heljan Di3.623 were used for the Heljan Di3.602 with GM logo project. This left me with a 623 without window glass. I decided to renumber this spare locomotive. The only real option would be the Di3.622, because it has the same cab 1 window construction. This page shows a few images from this conversion project.

I used Heljan MY glass for cab 2 and NMJ Superline gitter to install the typical Norwegian cab 2 setup.

Carefully masking the old number and removing it with some airbrush thinner and a Q-tip. The new number is applied to the model, I used the Woodland Scenics letter sets as I couldn't find another appropriate decal set.

The locomotive has been renumbered and shows its two faces. Cab 1 with the new glass and cab 2 with the old style with iron bars (gitter).