Also, I don't know if you were applying the term to the road of the crossing involved in this crash, but this road is not one I would characterize as "well used"; more like "exceedingly rarely used" (thus the lack of active crossing protection).
Finally according to the previously referenced Trains Forum thread ("Posted by blue streak 1 on Wednesday, June 29, 2022 11:32 AM"), the railroad existed 60-70 years prior to the road in question. I believe it is this circumstance which places the onus on MODOT to defend the users of their later-arriving road from hazards associated with rail traffic on the preexisting BNSF line (with BNSF being an involved party).
I understand citing posts another public forum does not necessarily meet the gold standard of citations, but all of these facts align with my preexisting understanding of the situation.
[0] https://en.wikipedia.org/wiki/Southern_Transcon calls out Mendon, MO as a station on the Marceline subdivision