Catch Ya' On The Flip Flop

Does anyone know of a transit system that, during certain peak times, has trains in a heavily traveled direction regularly making every third or fourth stop to speed up the trip and passengers to intermediate stops would take less crowded trains going the other way making all stops to complete their journeys? Of course with fare inspectors giving the passengers the benefit of any doubt or having their role changed to crowd control.

It would be like A and B stop operation except that the trains in the affected direction are not labeled and maybe they are all A trains.

This might work out well after ball games. Baltimore's light rail, leaving Camden Yard in both directions, comes to mind as a possible location.

In NYC there are subway with expresses only in one direction at a time. These are on lines that have three tracks.

I'm thinking of one direction with expresses and no locals, and in the other direction locals and no expresses.

So what you're proposing is offpeak all stations get a train, but in certain peak times in one direction you'll then eliminate service to some stations deemed to be local, but provide increased service to some stations deemed to be express, expecting the local passengers to ride past their stop, then change to a local train to return to the stop they had missed.
Ok, I can try to imagine that there must be some combination of number of stops, speed of track and train, number of outbound expresses that turn around and return as locals, and length of route where that might result in reduced wait and travel time for all passengers. Or at least reduced travel time for passengers destined for those express stops and increased service for passengers travelling in the return direction.

And I know of some people who like to catch the express that goes one stop past theirs. Especially if the express comes first, and has enough empty seats. Another example is New York Coney Island, the B D F and N all run from there to 34th St and 6th Ave Manhatten. I'm sure there must be somebody who wants to go to 23rd St, local stop F and N, who at least once in a while takes a B or D to 34th St. But most of the folks who have to backtrack to their local stop will probably be worse off than they would have been if there was a direct train.
And meanwhile those local people are taking up space on the express train, and contributing to its station dwell time, which might have been better managed in a more traditional express-local arrangement.

And you have folks at the local stations who want to go outbound who then have to travel inbound first on those less crowded trains you refer to, but then will contribute their bodies to an outgoing express train. And the really disadvantaged person who want to go outbound from one local station to another, they have to take 3 trains: local the wrong direction, express the correct direction past their origin and then past their destination, then local train backtracking a second time.

I've never heard of it done for regular service, only for breakdowns or local track out of service. I don't see much advantage to it. You'd not only need 1 major starting point, such as your example Baltimore's Camden Yards, but also major debarkation points. But a rising tide of passengers tends to lift all stations' usage.

In Chicago, CTA's Purple line express trains runs non-stop in rush hours between Howard and Belmont, with parallel Red line trains making all local stops in between. Some folks do indeed ride the express segment on Purple, then double back a stop or two on the local; and until a year ago, it was especially common during baseball season with Cub fans heading to Wrigley field, next to the Addison station, which is the next stop north of Belmont. Before, fans going to the game coming south from Evanston would ride Purple express to Belmont, then pick up a Red line train heading north back to Addison; now, Purple line trains in both directions actually make the Addison stop on game nights. Frankly, it's a move that should have been made long ago, especially with Red line trains from downtown during the evening rush already packed to capacity with regular commuters and Cub fans on game nights, squeezing in more folks at Belmont is already a challenge without adding another mob of Cub fans just off a southbound Purple line train to the mix. Glad the CTA brass finally came to their senses...

Am I pulling this thread too far off topic if I mention the phenomenon of getting on a stop or 2 before the terminal and riding to the end to get a seat for the return? I've noticed it in New York 7 line, evening folks get on at Grand Central or 5th Ave and ride to Times Square. Often PM rush trains pull into Times Square already full.