Sunday, July 17, 2011

No steering wheel!

A question was asked this week by @levis517 about how tram track switches work. It's frequently a question asked by passengers, especially tourists, who seem to quite calmly point out the lack of a steering wheel. Anyway, I've decided to delay (yes, PT puns thick and fast) the article on Short Shunts and instead answer this rather not-so-modern mystery.

There are 2 basic types of points - The first are Manual, where you see us get out with the giant tuna tin openers (called Point Bars) and click them over. The second are Automatic or Electronic. The system is set up in such a way that if electronic points fail, we can always get out and change them manually. Anyway, check out the picture below:
You should notice (if you squint), there are some white dots on the road inside the oblong. One, two, then three. The circle shows a lantern (or set of traffic lights) that indicates the direction the points are set to. In the case of Kew Junction here, if I was a #109 and wanted to turn up Cotham Rd, I would twist the points switch on the console as I approached the first dot. Between the first and second set of dots, there is a transponder that picks up the signal and switches the tracks. If I was a #48 continuing along High St, I would simply not touch the switch, as the default signal is "straight".

This second picture shows the lantern closer and while I have highlighted the opposite set of points, it does give you some idea of how the direction changes. This next pair of photos is a better set:

This shows the approach to Balaclava Rd from Hawthorn Rd. This is a unique junction in the system (and one of only two on the planet) in that a tram can turn in any direction from every direction. You can see the white dots and the lantern on the left indicating the points are currently set for a right turn. If I wanted to go straight, I would simply approach this without touching the switch, and as I pass over the gap between the first dot and the second set, the points would switch over.
Final photo shows the points are indeed set for the right:
That little lantern on the left in this picture indicates that priority turning lights can be activated at this location, but more on those another time.

I hope this clarifies any questions about trams turning. It's a fairly old technology and does have a habit of breaking down (electrics + outdoors + "wait till it breaks" = problems), but on the most part they are quite reliable. Only once have I had a real fright and that was when the points failed to change. I got out with the point bar to change it manually and just as I slipped it into the hole, BOOM! They flicked over. Usually if they fail, a horizontal bar appears. Oh, and if a tram behind comes up too close before the first one has cleared, the points remain set. I should say "usually" because part of our training is that if something can go wrong, it usually does when you're on your last run.

LEGAL BULLSHIT
YES, I'VE USED GOOGLEMAPS AND USED TWO EXAMPLES OF AUTOMATIC POINTS. THIS DOES NOT MEAN THAT I COME FROM ANY OF THE DEPOTS WHO USE THESE ROUTES. I USED THEM FOR SIMPLICITY AND INTEREST. I HAVE NOT REVEALED ANYTHING BEYOND WHAT ANY DECENT DRIVER WOULD DO IF ASKED BY A PASSENGER. IF YOU'RE TRAWLING THE INTERNET LOOKING FOR EMPLOYEES WHO ARE POTENTIALLY CAUSING DAMAGE TO THE COMPANY OR THE GOVERNMENT, I SUGGEST YOU FIND SOMETHING MORE PRODUCTIVE TO DO.

12 comments:

  1. Thank you so much for this. It has annoyed me for about 2 years now, and I couldn't apply the train switch mechanism to it. I also couldn't explain why drivers only sometimes stepped out of the tram with the can opener and wondered how they might remotely be switching tracks.

    I work right near Balaclava/Hawthorn Roads so thank you also for including that junction - I think it's beautiful (that might be an odd adjective to use to describe tram tracks :p) but it's also the one that's plagued me the most as 16 after 64, and 3 after 16 seem to seamlessly know where they have to go. It's very graceful (more odd adjectives).

    I also find it funny that there are other people who ask about this most of whom are tourists because I'm not Australian - surely they're curious to know as well? Or are you all taught this at school?

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  2. Thank you. I had been looking at those painted dots on the road and the corresponding dots in the driver's cab. Now I understand!
    Fortunately as a native Melbournian I never had any fears about trams not having a steering wheel. In fact when driving my car I often comment 'trams can't swerve' (ie. don't pull out in front of them!!!)

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  3. I've been peeking over drivers' shoulders at intersections like an annoying passenger.

    Sooo.... what's the third set of dots for? Sorry I am full of questions about trams, there isn't enough written about them :)

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  4. The third set of dots represent the end of the signalling section. If you happen to pass the three dots whilst another tram is yet to clear the points, the direction will remain set for whichever way and not change.

    As for being annoying, having a peek or asking a question at the right time can be fine. It's those who stand right next to the window, blocking the doorway, yelling into a mobile about which Masterchef they'd like to have sex with that really annoy!

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  5. Great post, thanks for posting it. I've always wondered how the track switching thing worked on trams. Will definitely be subscribing to your blog :)

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  8. Thanks a ton for this fruitful article. It annoyed me as hell before wondering how does turning work, to a point that I found an intersection with less pedestrian flow and kneel on ground trying to figure out how does the mechanic work yet to no avail.

    Trams are so cool!

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  9. As often visitors from WA we have been in awe of trams turning corners. Tonight we are thrilled to find out how it is done. Just about up there with San Francisco cable car technology!

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  10. As often visitors from WA we have been in awe of trams turning corners. Tonight we are thrilled to find out how it is done. Just about up there with San Francisco cable car technology!

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  11. I was looking for how the Trams in Prague steer and I found this page. I guess it would be very similar if not the same? Trams in Prague seriously hoof it when they have a clear section of track. Great fun to ride. ��

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