Is the “Beltway Stop" a popular metaphor meaning a concurrence of events or things?

The Capital Beltway is a freeway encircling Washington, D.C., and as Peter's comment states is often used as a metonym for the Federal Government and the associated Establishment. "Inside the Beltway" thinking, for example, refers not just to the opinion of members of the government, but to the consensus of the journalist/lobbyist/pundit class that lives there. ("Outside the Beltway" is alleged to be the opposite, although the editors of the blog of that name seem mostly to reside inside the Beltway.)

There is also a "Capital Beltway" station on the trunk railway line that goes from Washington to New York and Boston. I believe the author here is extending the metaphor of the Oscar competition as a race by suggesting that it has made a stop at the Beltway, to connect to these particular politics-themed movies.

(Incidentally, the Beltway when under construction was called the Circumfrential Highway. There's a reference by that name in some-or-another early 1960s political novel, that Google won't find for me.)

It's not a common idiom, and I'm a little puzzled as to the writer's intent here.

The Beltway is a key highway in Washington DC, so "Beltway" certainly just refers to Washington itself.

"Beltway Stop" may be an allusion to a "pit stop" in a racing track - a refueling/refitting point in the race. This fits the race metaphor, but I don't see how the movies are refueling/refitting.

It may also be related to "bus stop" (as StoneyB said in a comment) - a stop along the journey to the Oscars. This is more in line with a statement later in the article referring to the "Oscar trail's detour into Washington", but it doesn't quite fit with the race metaphor and I'm not really sure how the movies are supposed to be 'pausing' in DC.

In short, I think it's a weird choice for a title.

A stop can mean a layover. So the connotation of the headline is that there are several movies contending for an Oscar that involve the politics of Washington in addition to the various themes of other Oscar contenders.