locomotives, in hot pursuit

I brought a history book with me and read about the Mexican Revolution of 1910.  It seems more like a several-sided civil war, with generals and armies popping up around the country, and all distressingly bloody.

One part I liked about it, though: there were at least two locomotive chases.
   
Forced out of office in 1911, old don Porfirio Díaz, the closest thing Mexico ever had to a president-for-life, fled over the mountains to Vera Cruz with a train-full of loot, pursued by a train-full of Rebels.  He made it to a waiting French warship and ended his days drinking champagne and bouncing chorus girls on his knee in Paris.
    A few months later, Pancho Villa, having overstayed his welcome in the capital, fled north, pulling up tracks behind him, hotly pursued by Obregón, laying tracks as he came.
   
I like locomotive chases.  There was a brief window of time when they were practical; now, alas, gone.