Apologies in advance - this is my first question so I'm probably bound to be doing this wrong, but seeing as it's Trains and Railroads week I thought I might post a question which I've had for a while.
I did my high school in Australia and vaguely remember from history class that Queensland, New South Wales, and Victoria ran different track gauges before federation. From what I remember, because of this difference, federation nearly did not happen since no state wanted to acquiesce to another (I'd actually appreciate it if someone confirmed whether or not this was true).
So my question is: Were different track/rail gauges an issue which arose in the unification or federation of countries? Perhaps the United States came before railroads took off, but how about other nations? Did the different states of Germany or the different provinces of Italy have different track gauges before unification?
Many thanks for reading and for any answers!
Among the many issues that Italy faced in it's trek towards unification rail didn't actually played a heavy roll in it. Why? The lines already crossed throughout much of the northern Italian areas, and were already connected. The 1853 inauguration of the Turin–Genoa line would be instrumental as it would be connected to not just France and Switzerland (France becoming an invaluable ally in the Italian wars of independence), but also to the Austrian controlled Lombardy–Venetia lines.
The other thing to take into account is that the rail lines of Italy were very basic prior to the Risorgimento and much of Italy did not have rail lines. I actually went over this in this question on Mussolini and the trains if you want to check it out in more detail!
The US did indeed exist prior to railroads, but that didn't mean there weren't any issues. Rail companies were very regional early on, and adopted their own gauge based on what they thought was best. As they expanded and began to cross state lines, this became an issue. Freight being shipped by rail would be delivered to a city where it would have to be unloaded from one train, then re-loaded onto a different train - with a different gauge - before continuing on to the final destination. As railroad traffic became more critical to the shipment of freight, the various companies gradually began to work together towards a single rail size, which eventually would be called Standard Gauge.
During the Civil War, the Pacific Railroad Act of 1863 was passed, dictating that any federally funded transcontinental railroad be built to standard gauge. Being the middle of the Civil War, this naturally meant that a number of states were not obliged to consider the designing their railroads to be Standard Gauge. In the decades after the Civil War, it became apparent to businesses that the transferring of goods between freight cars due to gauge differences was only hurting the delivery of goods, and by extension their overall value as a commodity. The southern rail companies decided to coordinate their efforts to convert to a size compatible with the north.
"A formal conference in February 1886 made concrete plans, choosing the Pennsylvania Railroad's 4'91" gauge and setting May 31 and June 1 as the main dates for track work. Over 13,000 miles of track were converted on those dates, and over 1,500 miles of branch lines and sidings within a few days before and after."
Now, the gauge selected wasn't exactly standard gauge, but it was close enough that cars could be used on both without major complications.
This answer is by no means the most detailed, and I make no claims to be a railroad expert. However, there is a great article by Douglas Puffert that I recommend to get an introductory idea of the development and complications of railroad gauges in the US. You can find that article here, conveniently in PDF form: https://campus.fsu.edu/bbcswebdav/users/jcalhoun/Economic_Standards/Puffert%20-%20The%20Standardization%20of%20Track%20Gauge.pdf