Several years ago I donated, to CRRM, approximately 8 very large Rio Grande bridge ledgers for Utah..
(Which I now trluy regret)
The period covered roughly the 1890 to 1936 time frame.
These ledgers contain information for every bridge, trestle, culverts, etc. , main lines and branches for entire Utah.
Included were drawings of each structure along with date built and various maintenance and changes that occured during this period.
After all these years I cannot say if these items still exist.
Perhaps contact with CRRM would develope some information
Jimmy