Runaway! (1973)

While people often ask about the real event this film is based on, or how it compares to Runaway Train (very different, IMO), there is a little known made for TV movie from the 1970s that's very similar to Unstoppable, called Runaway! that I have never seen.

Tell me if this sounds familiar.

http://www.imdb.com/title/tt0070615/combined

From Wikipedia:

"A passenger train begins descending a long downhill grade, only to discover that the brakes don't work...it continues to gain speed, and the brakeman is lost... It is anticipated that the train will derail at a sharp curve once it reaches level ground, and emergency crews stand by there.

A last desperate measure is tried: a locomotive will join the line after the runaway train passes, chase and latch onto the end of the train, then pull the train to a stop."