Photo taken by Patrick Feller
License: Creative Commons Attribution (CC BY)
View this photo on Flickr
BH Photo #242484
Um, this is not a KCS line (although they have trackage rights). The original line was the Houston and Texas Central, followed in 1917 by the Galveston, Harrisburg and San Antonio railroad parallel to it. Those were both taken over by the Texas and New Orleans (a subsidiary of Southern Pacific) until it was merged into the SP. UP became the owner when they merged with SP.
So the correct owner is UP, along with the other bridges you have listed on the UP Houston Subdivision (Memorial Park, etc).
This also goes for your BH 54379 entry for the Katy Road bridge.