Russell Crowe has Ridley Scott, Leonardo DiCaprio has Martin Scorsese and Denzel Washington has Ridley's brother, Tony Scott.  What do they have all have in common?  Director and actor collaborations that have teamed up numerous times for critical and box office acclaim.  Now, Variety reports the Washington/Scott combo are set to reunite for the jaw-dropping fifth time in the new Fox thriller "Unstoppable."

The action flick would find Washington as an engineer who jumps in a locamotive with a young conductor to chase down a runaway rain carrying a cargo of dangerous chemicals.  Basically, while it's loosely inspired by a true event, it's "Speed" on a train.

Washington and Scott previously teamed up for "Crimson Tide," "Man on Fire," Deja Vu" and the upcoming remake "The Taking of Pelham 1 2 3" with John Travolta.  That thriller hits theaters June 12. 

The Oscar-winner recently finished the Hughes Brothers' post-apocalyptic flick "The Book of Eli."

Fox hopes to begin shooting "Unstoppable" this fall.  That would put Washington's involvement in the expected new MGM franchise "The Matarese Circle."  No word on whether that production, which Tom Cruise was also rumored to be starring in, is anywhere nearer to production.