I found a 1961 operational manual of MLW locos RS-30 & RSD-30. Some pages are missing but the drawings and most of the sections are complete. I will soon scan and upload text but just to give you a preview I am putting the engineering drawings and a pic of the locos. As you can see this is the ancestor of our Meter Gauge YDM4. Please note the toilet and the wash basin in the short hood!