Based on a quick search, that does not seem to be true. The title of the movie comes from the title of the book it is based on. The book's author has given some explanations for the origin of the title that do not involve Glasgow trains. [0] It seems the name for the subway comes from the movie. There also seems to be some dispute about the usage of that name for the Glasgow subway. [1]
[0] https://en.wikipedia.org/wiki/A_Clockwork_Orange_(novel)#Tit...
[1] https://en.wikipedia.org/wiki/Glasgow_Subway#Nicknames