People have been jumping over turnstiles at MTR stations - but they aren't turnstiles, they're gates. The word remains, though the thing has gone. 'Turnstile' now appears to mean 'any barrier that one has to pass through, usually by paying, in order to reach a certain venue'.
The word 'turnstile' preserves an old word from the countryside, 'stile' - which is a simple ladder fixed to a fence so that one can climb over it. One or two people on Geoexpat have mis-spelt the word 'turnstyle'.
It's not uncommon for words to remain in use, though the thing has gone, or changed. For example, 'steamroller'. Where's the steam?