BART is so familiar that most of us stop noticing how unusual it is. But under the hood, this system is packed with weird engineering choices, world-record infrastructure, and some very Bay Area problem-solving.
1) BART does not use “standard” railroad track spacing
Most rail systems use the global standard gauge (4 ft 8.5 in). BART famously runs on a much wider 5 ft 6 in gauge — sometimes nicknamed the “Indian gauge” — which affects everything from wheelsets to maintenance equipment. (Bay Area Rapid Transit)
2) BART trains can auto-slow before the shaking arrives in an earthquake
BART is an early adopter of earthquake early warning (ShakeAlert). If the system predicts strong shaking (BART cites intensity above a threshold), trains automatically begin slowing to about 27 mph, removing human reaction time from the equation. (Bay Area Rapid Transit)
3) The Transbay Tube is basically a giant underwater “Lego set”
The Tube wasn’t bored like many tunnels. It was built on land in 57 huge sections, towed out, and sunk into place under the Bay. BART notes each segment averaged roughly 330 feet long.
4) When it opened, the Transbay Tube was a world leader in its category
BART says the 3.6-mile Transbay Tube was the longest immersed tube tunnel in the world when it opened (1974) — and it held that title until 2010. Also: it sits about 135 feet below the water’s surface at its deepest point.
5) The “third rail” runs at a seriously high voltage
BART converts incoming utility power and delivers 1,000 volts DC to the third rail that powers trains. That is one reason the system treats track areas as extremely hazardous even when it “looks” calm.
6) One part of the BART map is secretly a different kind of railroad
The Antioch extension (“BART to Antioch”/eBART) runs diesel multiple-unit trains on standard gauge track (4 ft 8.5 in), not BART’s broad gauge. That difference is why riders make a cross-platform transfer near Pittsburg/Bay Point instead of taking one train all the way through.
7) Ridership is still in rebuild mode — but the trend line has been up
BART’s own ridership reports show 2024 average weekday ridership around 165,502, with total trips up year-over-year (about 50.7 million trips in 2024, up 5.3% from 2023). And BART reported that October 2025 hit its highest average weekday ridership since the pandemic period began.
