I was led to believe the multitude of threads and Rail Gauges stemmed from individual companies that didn't want their products to be "common" and easily adapted/copied to fit various fittings into the opposition's goods, just like early Railways from over 100 years ago, were all private and independent and wanted to protect their Line from being used by other Rail Operators who would have just transferred their rolling stock & Locos (after changing bogies), onto their adversary's Line and gain more delivery distance. They could never come to an agreement as one Line would ALWAYS be longer or shorter and quarrels broke
out before any hope of resolution could be had, plus the Lines with longer track routes sought compensation from those with shorter Lines, plus how important or serviceable one Line was over the next. No solution was ever found.
So they all went their separate ways and created separate gauges all over Australia by the hundreds. None lasted very long. Now all gone.
SCREWTHREAD FOOLISHNESS WAS BAD ENOUGH .. RAIL FOOLISHNESS HISTORY SAW SO MANY LIVES & FORTUNES LOST
At Sorrento near the end of the Mornington Peninsula on top of the cliff overlooking the Ferry Terminal, there is a saved section of Rail plus a Memorial of the actual line that ran somewhere nearby, with no connection to the established line that reached as far as Red Hill. If anyone's interested, I can dig up photos I took when our Car Club (Mornington Peninsula Historic Vehicles Club) crossed the the "Rip" to Queeenscliff to join in festivities with another Club, which alternates each year when they come over to our side. Photo will show details on the Memorial Plaque, plus pics of Station and Line.
The most successful and ever-financial line in Victoria to this day is the extension to Lysaghts Steel Mill near Hastings.