I have the same "hangtime problem", when placing subway stations. For example, if I have a fully grown city, and I want to plop the Ninja Boulevard station
(https://www.simtropolis.com/stex/details.cfm?id=3194), the ground textures dissapear, when the station is ready be plopped. But after ploping it, and when closing the misc trans. menu, or switching to another tool, it takes few minutes for the textures to reappear.
I have discovered one el-rail station (with bus and SUB), that doesn't bring out that hangtime when plopping.
Modern ElTrain station by Brenda_Xne - https://www.simtropolis.com/stex/details.cfm?id=19250
Where does that difference come from? Is it possible ot avoid this problem with all subway lots?