This nice shed I found in the last special issue of the Walthers catalog.
This plastic kit comes in grey color. I painted it with silver acrylic paint. weathering is done by airbrush-color "black" using a nearly dry brush.
The kit comes with a complete history and a copy of the blueprint. The shed was made for D&RGW in the 40's.

What aew you going to use it for? Trackside storage? If there is a garage door on the other side, you could leave it open and fill the shed with small items to make a real scene out of it.

You are right. It's forseen in the instructions of the kit to open the door by a cut with an knife. But at the moment I'm only building structures, lay the track and do some model railroad basics. Later I will integrate a lot of more details but now it's to early.
But thanks for the ideas!