Here is a US spy satellite photo from the 1980’s of the Tractor factory. As you can see, the area has been rebuilt. Yes, I have been behind this area and walk ever existing street from the time of the battle. Russian federal law prohibits digging and this type of salvaging without being registered and having permits, but it is done all the time.
I found the book years ago on German eBay!
Russ
www.fireonthevolga.com