This is a completely over-the-top story that will scare people who do not know the detail of the trains from Central London to Gatwick.

Gatwick Express is one of three separate train operators on this section of railway. There are alternative services provided by the two others, including to Victoria, which operate at least as frequently as Gatwick Express do. The linked BBC article makes absolutely no mention of this; their story appears just based on the union press release.

There may be some standing on the journey as a result but nothing to really change your travel plans about.