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Showing content with the highest reputation since 10/08/19 in Posts

  1. 2 points
    I'm not sure what the item is, but I'm pretty sure it doesn't relate to the trams. The trolley pole of a tram is insulated all the way to the end, with only the small wheel on the tip being live. The 550V DC was then carried down a heavy cable inside the hollow metal pole, first to a circuit breaker, then to the lighting circuit and controllers and then on to the motors. The pole was turned either by the conductor pulling on a rope from ground level, which was permanently attached to the trolley head, or by using a seperate bamboo pole when no rope was fitted. What it may be (although I've never seen one anything like this) is a device for recovering a "grounded" tram. Grounding occurs when the wheels become electically isolated from the track, which forms the negative return for the electrical circuit. Besides stopping the tram, grounding can be quite dangerous as the high voltage DV tries to find the shortest route it can from the overhead wire to the tracks. If it can't pass through the motors etc and out through the wheels there is a very good chance it will pass into the body of the tramcar. If this happens, anyone standing on or near the tracks (particularly on a damp day) who touches the tram will likely complete the circuit and experience a 550V DC shock. If they were to grap a handrail the shock would likely make theior muscles contract, meaning they are unable to let go, so prolonging the peroid of shock. The official way the Tramway Museum at Crich deal with a grounding is for everyone aboard the tram to be kept aboard. One of the platform staff (usually the conductor) then JUMPS off, making sure their body entirely leaves the tram before any part of them touches the ground. Next, using either the iulated rope attached to the trolley or a bamboo pole which can be found at staategic points along the route, the trolley is hooked down off the wire to cut off the electrical supply to the vehicle. The tram is then pushed or pulled ontpo a cleaner bit of track, where hopefully it's no longer grounded when the power is restored. This can be checled easily by turning the saloon lights on. There are other simpler 'dirty' methods for dealing with a grounding. One involves jumping from the tram and then throwing a bucket of water under the wheels. The water is a pretty good conductor at these voltages and will also swill away some of the dirt from the rails. This trick usually works and was common in the days when fire buckets full of water were common place. The other method, and also the most risky, is to jump from the tram with the point iron in your hand. The point iron is a thing a bit like a crowbar that all trams carry for changing the points. Just infront of the tram you have to wedge the end of the point iron into the groove of the track, making sure it is in contact with good metal. Then, with a swift and positive motion, ram the other end of the point iron down across the fender of the tram, scraping off as much paint as you can as you do so. The theory is because you made the connection with the track first, when the point iron touches the tram the current travels down the metal bar to the track without harming the person holding it. However if you get it the wrong way around and touch it on the tram first, then you'll likely get a 550V DC whack! I knew a chap who made this mistake while on a special tram tour in Sheffield in the late 50s or early 60s, which ran over some disused and hence dirty tracks. He didn't remember much about the shock, but woke up on the opposite side of the Moor to where he started! Luckily he lived to tell the tale! The thing on the pole could be something for wedging in the track and then attaching to the tram. Or it may be something for holding down the trolley if no rope is fitted and it can't be tied to the rear fender, which is the normal practice.
  2. 1 point
    Hi Folks, Now available as a podcast. Link to listen here - http://smarturl.it/MyLifeInTheMosh All the best Roger
  3. 1 point
    Been back to the Strines today, so I photographed the hare, who had a bad Christmas that year.
  4. 1 point
    I remember the dancer he was called Mighty Melvin
  5. 1 point
    Searched where, and what I could MA, I have a tendency to go along with your suggestion of 'Smithfield'
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