Looking for a Tasmanian devil
I don’t think Ron and Gerry even saw one of those creatures. Let me explain:
Our friends Ron and Gerry live in Perth, Western Australia. Those two gentlemen are seemingly always on the move. If it’s not Berlin they are visiting, it’s got to be Paris, or, maybe Tasmania. This island state off the southern coast of Australia is known for its ruggedness and wildlife. And it also has a steam preservation railway! I have always wanted to go there, but it is an awful long ways from Washington DC.
So, Ron and Gerry beat me to it and, just to make sure that I am envious enough, sent me a bunch of photographs and some video of their visit to the “West Coast Wilderness Railway” in Tasmania.
This heritage railroad started out as a mining railway in 1897, hauling copper to the port at Strahan.
The railroad was built as a narrow gauge line, with the typical British 3 feet 6 inches between the rails. Due to the rugged terrain, a pure adhesion railway operation was impossible at the time. One of the engineers involved in planning this railway suggested that a rack rail system be used for the steepest parts of the railway. It was his opinion that the “Abt” rack rail system be used. Apparently his suggestion was met with some skepticism, since that particular system had been invented only in 1882 by the Swiss engineer Carl Roman Abt. The first railroad to use this system was a line in Germany being built in the late 1880’s, so reliability and safety regarding Mr. Abt’s idea were still somewhat uncertain. Somehow though, the engineer’s idea was eventually approved and the Abt rack rail system was used. That turned out to be a very good call. There are other rack rail systems around, but the Abt system has proven to be the safest and most used system on rack railroads.
So, why do we need rack railroads? Consider how railroads work, particularly locomotives. The locomotive steel wheels run on steel rails. The contact area between that wheel and the rail is about the size of a large postage stamp. That is an advantage, as there is little rolling resistance to get a train moving. However that advantage turns into a huge problem if the track is wet, the train tries to accelerate too fast or the track is too steep. That “steepness” issue, generally referred to as “gradient”, comes in when a train line goes up a mountain. Above a certain grade percentage a pure adhesion railway can not make it up a hill. The wheels on the locomotive will just spin and start slipping. The steepest gradient on a mainline railroad in the USA is about 4%. There are steeper gradients, but they tend to be on tram lines (Pittsburgh at 9.1%, Lisbon Tramways at 14.5%) or logging railroads with purpose built locomotives like the geared Shay engines at the Cass Scenic Railroad (11.1%). Very broadly speaking, a locomotive hauled train or DMU/EMU, needs a rack rail system above a gradient of 10%.
Rack railway systems have been around for quite some time. The British engineer John Blenkinsop already patented a system in 1811. Eventually about a dozen or so systems had been invented. However the idea was basically always the same: a powered cogged wheel somewhere on the locomotive would engage with a “toothed” rail somewhere on the track:
Just two of the different approaches to cog railroads. Photos from Wikimedia Commons.
As can be imagined track turnouts or switches can be a nightmare on cog railways. Abt’s invention simplified those. Further he offset the two or three rack rails in the center of the adhesion rail. This insured that the cogs on the locomotive driving wheel are always in contact with the rack rail, thus increasing safety. Eventually some form or other of the Abt system was used by the majority of cog railways.
Abt system track at the Brienz Rothorn Bahn. Photos by Ralf Meier.
But back to Tasmania. Here, in no particular order, are Ron and Gerry’s photographs and video:
A short video of the train ride is here.
Unless otherwise noted all photos and video by Gerry Coles/Ron Cleary (Pentax K50)
1 Comment
This is awesome 👏