Modern synonym for turnstile?

I searched images. This is called a turnstyle/turnstile:

see HERE for lots of related terminology.

Even something fancy like this is still called a turnstile:

This particular item is a 2MGST-5 Face Recognition and Thermal Detection Access Control Swing Turnstile. There are many similar examples out there such as in Flexibility, Efficiency, and Security: The Benefits of Optical Turnstiles.

Alternatively it can be called a gate.

Faregate in mass-transit rail stations

WMATA (link is to pdf, quote from page 11)

Every Metrorail station mezzanine has an extra-wide faregate to make access easier.

BART

The Richmond BART Station now has a newly designed accessible fare gate prototype to test BART’s next generation of faregates.

And wikipedia

Thus a turnstile can be used in the case of paid access (sometimes called a faregate or ticket barrier when used for this purpose), for example to access public transport, a pay toilet, or to restrict access to authorized people, for example in the lobby of an office building.

Taking my cue from your example sentence

"For our trip tomorrow, let's meet at the station just outside the turnstiles."

Each individual device that you pass through to enter or exit a rail station is a ticket barrier.

Mind you, to go by what Google came up with when I googled the phrase, it seems that even the ticket barrier might soon be a thing of the past. Articles in the Daily Telegraph and the Independent on plans to replace them with sensors. Tripadvisor Q&A about present-day rail station ticket barriers.

A line of them is called a gateline or gate line, though this might be a more technical term.