"A teenager travels back in time and nearly unravels his own existence."
"An insomniac develops an underground boxing ring to feel complete."
"A working stiff begins to drastically change his life to impress his daughter's best friend."
"A deceased man travels from Heaven to Hell in search of his late wife."
"A widowed husband with short-term memory loss searches for the man who killed his wife."
"A wealthy and confident man meets a woman who sweeps him off his feet before an ex-girlfriend nearly destroys his life."

Can everything, good or bad, be summarized in one sentence?

A terrorist plants a bomb that will go off if a bus goes under 55 MPH. A shark terrorizes a beach-side community. There's a bunch of fucking snakes on a fucking plane. You get the idea.

Pretty much all action films are high concept. And, don't get me wrong, Pelham is definitely high concept (as you can tell by my one sentence synopsis), but the characters are fleshed out just a bit more than the average flick.

I'm not challenging you negatively here, but if you could elaborate on something for me I'd appreciate it. You describe this as being 'high concept'. What action films would you categorize as being 'low concept'? My mind goes to films like 'Bourne' and 'Bond' immediately, but those are few and far between. It kinda feels like a ton of action films rely on the premise to achieve their intensity and narrative focus quickly, while taking the saved time to execute full blown action sequences. Whether or not this is negative is entirely determined by each film, I guess.