Seriously, I take BART daily and it would benefit greatly from the biggest gates they can find. So many of BART's problems are caused by fare evasion.
NYC just puts in very strong stainless steel turnstile cages 8 feet high.[3]
[1] https://www.sfchronicle.com/bayarea/article/BART-s-new-stack... [2] https://www.nbcbayarea.com/news/local/BART-Fare-Evaders-Caug... [3] https://www.nydailynews.com/new-york/cagelike-subway-turnsti...
Tokyo has probably the best-designed faregates I have ever seen and I wish NYC would copy them.
That's so New York, to have an in-your-face un-jumpable turnstile.