There appear to be three bridges described in your example. The examples you posted look like they are from field notes. The quality and format of the notes depended on the two or three people in the group that did the field work for particular ICC accounts within each Val section. Different accounts, 16 for depots for example, had an architect and an "ICC man" go to each location, usually in milepost series within a Val section. While the field notes are good to have, the inventory submitted in 1927, or the Val section summaries would be the most accurate and complete.
SRHA archive volunteers are cleaning up the Val section summaries now. They will be available to anyone that goes to the archives for research but we have not decided to simply put all 2,200 summary scans on line. The detail pages are in the thousands, not all have been scanned. I've attached an example of one of the summary pages. (I note that NC Val Section 27 is NOT in the SRHA (i.e. Southern) file. It jumps from section 26 to 28 as the A&Y was responsible for the valuation of its railroad. The originals of everything should be at College Park, what SRHA has are the carbon copies of the 1916-27 study and the 6-31 and 12-31 changes sent to the ICC on paper every year until about 1965. The bi-annual reports are excellent to show "As and Bs" (Additions and Betterments) and when an item was removed from the accounts. Both the Southern and CofG summary reports have many hand written entries showing when a depot, water tower, etc was demolished, destroyed by fire, etc.
I think I posted the following some time in the past but here is a Google Drive link to the 20 or so page ICC instructions:https://drive.google.com/drive/folders/1vwp_eG1F2Kh9z1fcYy_gEfjlh8O6_y-m?usp=sharing
Note that the SRHA archives are the work of volunteers and people that donated cash to purchase private collections. We would appreciate hearing comments and suggests about HOW we should make copies or scans available. Should we establish some form of "subscription" that allows people to access and download scanned items, allow access only at the archives? Short of receiving a large grant to make everything freely available, some form of revenue needs to be established to help pay for the building, the electric bill, insurance, etc. Your comments please!