ELGERT FAMILY of USA

I am researching the Elgert Family from Germany; however during the 1800s and 1900s certain family members temporarily migrated to other areas now Poland, Czechoslovakia and returned to Germany. The 1st generation I have a record of is my great, great, grandfather Jacob Elgert(1835+/- to 1890+/-).None of the American Elgerts know Jacob's wifes name. I have Jacob's children:Michael August Elgert, Charles(?)Elgert & Lusie Elgert and all of Michael's children and I have created the Descendents
chart from Jacob's period to the present (2002).

The Elgert family owned a Castle (Elgertsberg) some where on the Rhine River, Germany and other lands in other parts of Germany..(before &/or)during Jacob's life; however I understand that he was constructing a railroad for Prussian government and they did not pay him; thus he sold the family properties and Castle to pay for the railroad (no bankruptcy in those days). It was the (Dubno to Rowno line - 60 kilometers)with a connection to Kiev.

Any information shared with me would be greatly appreciated' and I am happy to share what I have.