The cab doors do not open a full 90°, rather about 60°.
As youcan see, engineer’s door is modified, and fully open, while fireman’s is unmodified. This bothered me a little, as with doors open, I like them fully open. I investigated the cause, and found the handrail across the outside of the window was impacting the front cab wall. I removed the handrail, drilled the hole through with a #60 drill and pin vise, while holding the back of the door through the open front side window.
This shows the unmodified handrail. A re-check showed it better but not prefect. So, I trimmed the space between the handrail holes and window into narrow channels for the handrail to seat into with a sharp Xacto knife, once again while holding the back of the door through the open cab side windows.
This shows the handrail modified and basically flush with the door frame. Opens perfectly to 90° now and stays there.