Can anyone here point me in the right direction on finding engineering prints for a bridge located in Michigan. The bridge is on the former Jackson Branch of the NYC that is now operated by the Southern Michigan Railroad Society.

The line was officially abandoned by Conrail in 1982. Both the engineering departments of CSX and NS have been contacted with no luck. The bridge would have been constructed by the Michigan Central.

Some facts stolen from https://bridgehunter.com/mi/lenawee/tecumseh-railroad/

Facts

Overview
Pratt deck truss bridge over Raisin River on Southern Michigan Railroad Society
Location
Lenawee County, Michigan
History
Built 1896
Builder
- Detroit Bridge & Iron Works of Detroit, Michigan
Railroad
- Southern Michigan Railroad Society (SMRS)
Design
Pratt deck truss
Recognition
Posted to the National Register of Historic Places on December 4, 2001
Also called
SMRS - Raisin River Bridge
SMRS - Tecumseh Bridge
Approximate latitude, longitude
+41.94328, -83.94606 (decimal degrees)
41°56'36" N, 83°56'46" W (degrees°minutes'seconds")
Approximate UTM coordinates
17/255785/4647677 (zone/easting/northing)
Quadrangle map:
Tecumseh South
Inventory numbers
NRHP 01000572 (National Register of Historic Places reference number)
BH 52031 (Bridgehunter.com ID)

I too am interested in various Pratt truss bridges and would like to locate any archive that contains blueprints on these structures. Any help you can offer on this is greatly appreciated!