Changing The Gauge

On May 31, 1886 - all over America was a change that we live with which is one that goes unquestioned now.

This was when in the course of 36 hours, the Gauge of Railroad Track ( the distance from one steel rail to the other) truly became standardized.

The tale of the change in "gauge homogeneity" to 4 foot 8.5 inches

http://southern.railfan.net/ties/1966/66-8/gauge.html

and

https://kottke.org/14/09/the-days-they-changed-the-gauge

and

the best article on the change and its rationale is here . . .

http://trn.trains.com/railroads/abcs-of-railroading/2006/05/a-history-of-track-gauge

"The damage this movement did was much worse elsewhere. It festooned most of sub-Saharan Africa with a gauge (3 feet, 6 inches) poorly suited to the heavy mineral traffic its railways handled, and it beset India, Australia, and Argentina with serious problems of gauge incompatibility.

and

"Essentially, this interpretation (for wider gauge) is based on the fact that area-volume ratios of cylinders become more favorable as size increases. As a consequence, large boilers produce their output at a lower average cost than small ones. On a broad-gauge steam locomotive, the boiler could be larger and slung lower for greater stability. 

 The drawback is that wider width means more timber is used for the Railroad ties.