How do you get a train up a really steep hill? Even if it has motors or and engine powerful enough to climb a very steep hill, there is not enough adhesion between the rails and the wheels to allow such a steep climb. This problem afflicts trams too.
Well, all very well to use a counterweight to get a tram up and down a steep hill, but this is not practical for a large and heavy train.
Let us visit Lithgow, well ten kilometres short of Lithgow on the western flank of the Blue Mountains. At this point the mountains rapidly fall away to Lithgow's Valley below. A cry for a train was heard, from all parts of NSW west of the Blue Mountains. Twitter streams were created, a Facebook site set up, politicians flooded with emails and online petitions. Well, no not back in the mid 1860s. More likely local delegations were making representations to a their local members and to ministers.
So, how to get a train up a steep hill? It was probably an already tried and true method. You zig zag the train back and forth up the side of the hill. The train travels one way up the side of the hill, then reverses and climbs up a bit more and so forth until it reaches the top. Bit more organising to get the train up the hill than if straight track, but it worked well until there were so many trains to get up and down the hill, a lot of waiting time was involved at the top and the bottom of the mountainside.
By 1910 engineers were skilled enough to replace the zig zag railway with a dozen or so tunnels to get the train up onto the Blue Mountains and the zig zag train line was no longer needed.
Fortunately much of the system was left in place and restoration as a heritage railway began in 1975 and even today, it is an ongoing project.
Here is the website for the Zig Zag Railway. It is worth clicking on the link just to see the snow in the header photo.
Have I been on the Zig Zag Railway? Nope. Would I like to? Oh yes, well see it at least. Old trains aren't usually very comfortable. They clank and jolt a lot. Come to think of it, new ones are not so good either, for different reasons.
There are many photos on the net of the Zig Zag railway, but one picture I found tells a thousand words. I believe this mostest excellent photo is by Maksym Kozlenko Maxim75 . Well done to him. I do like a nice viaduct.