There's now a magic word which allows editors on the English Wikipedia to override the descriptions from Wikidata, per T184000. The previous method of accessing the descriptions using prop=pageterms now needs to be replaced with prop=description. The output from the new method is quite different, so there'll be a few changes that need to be made.
Old method: https://en.wikipedia.org/w/api.php?action=query&titles=Wagon%20Train&prop=pageterms
New method: https://en.wikipedia.org/w/api.php?action=query&titles=Wagon%20Train&prop=description