The Train Robbers (1973)

After her husband dies in disrepute, an attractive widow (Ann-Margret) hires gunslinger Lane (John Wayne) to recover a cache of stolen gold and clear her family name. The two set out for Mexico in search of the loot, but the journey proves more perilous than they expected. A mysterious horseman and a violent group of bandidos are also in pursuit of the gold in this shoot-'em-up that will keep you guessing.