Original Boston and Maine Valuation Plans

I'm trying to track down unaltered Boston and Maine valuation plans.

Boston and Maine Historical and NMRO both only have altered ones, and the unaltered ones that may exist in Billerica are inaccessible

Are there any other places I can find them (registry of deeds, state office, private collections) besides the ICC Archive? I have the ability to digitize them at no cost and am trying to avoid the immense cost of hiring someone to do it in D.C.

The end goal is to have all 2,000+ unaltered maps digitized and preserved.

I'm not sure the ICC kept every generation of map - the original mission from Congress was to document the then-current capital assets of the RRs as a starting point for negotiations if the US decided to nationalize them. So obsolete maps wouldn't be a priority to archive. What I've seen/heard about in academic or state libraries/archives is the last generation the RRs did. They were kept after the ICC mandate ended but eventually donated as more and more of the assets were written off and storing the maps was no longer justified.

I believe the B&M's original valuation plans were done over at least a year, maybe 2-3. So what you're looking for would be of historic value, but not a clean snapshot of the whole RR.

In somewhat of a reply/comment to jbvb, on the Maine Central's side, they made at least 4 linen copies of the unaltered maps. I know the whereabouts of all four, and know for sure that at least 2 of them are 100% original and unaltered. Boston and Maine Historical Society and University of Maine has unaltered ones, Pan Am has altered ones, and now I'm unsure if ICC is original or not.

I just cannot locate ANY linen copies of Boston and Maine (or Portland Terminal) besides the ones in Billerica.

I'm going to assume they made many copies when originally done for both backups, and to distribute to the various MOW offices to create blueprints for various projects and such?

I'm not convinced that they didn't make linen copies of Boston and Maine's valuation maps in 1914 and am not convinced that if they were made, were destroyed.