This is shocking to hear. I was lucky to visit John at his Pittsburgh home once, and also saw him many times at York. He was important in the Garden Show business, but Train collectors knew him as curator/owner of the largest, most-important Prewar Standard Gauge collection that will ever exist. John was very humble and kind, you never felt his importance just meeting and talking to him. His TM videos give only a hint of the size and completeness of his Standard Gauge collection.
John will be greatly missed.