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An Engineer in Wonderland – Train pick-ups and snow

train-pickups.jpgGot stuck on a train in the snow a week or so ago

The driver was great.

He told us exactly what the problem was, and exactly what he was going to do about it, and then he did it.

The problem was that the live rail was icy and the pick-up could not get enough power.

With limited power, the train could not get up the slight hill it was trying to climb.

So we waited for the proper contact to be made, and then moved forwards a few metres.

This process was repeated for half an hour or so until we reached the top of the gradient, and all was well after that.

Part way up, the driver re-booted the whole train, just in case its traction control algorithms were not available to the trains systems.

I didn’t even know trains had traction control algorithms.

Anyway, there were a few other tribulations before journey’s end, which our host also coped with.

I was so impressed with our calm and capable driver that I walked up and thanked him when I alighted.

Two things struck me while we were inching (centimetreing?) up that hill. 

First, just how efficient trains are, as resistance to movement seemed almost entirely to be dominated by mass and gravity, rather than friction and velocity.

Second, what a shame the current pick-up does not have an ice remover – a scraper or rotating brush?

Now I am curious.

Are there winter puck-ups?

Did the train have them?

If not, are they impossible?

Are they too expensive?

Anyone know any answers?

‘Alice’

Photo with thanks to Elsie esq. 

If you can answer this, respond below, or to alice@electronicsweekly.

No email addresses are collected for marketing purposes from responses to this blog.
I will keep it that way for as long as possible.

Tags: email addresses, friction, gravity, pick ups, whole train

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11 Comments

  1. 'Alice'
    March 22, 2010 16:30

    Thanks for that lot folks.
    If I get to run the trains (lets hope not) I will try a spinning wire brush at the moment, or pushing at the ice layer with a stiff plastic rod to break the ice while not damaging the track, perhaps fed from a reel.
    Then I can join that useless group of people who do arbitrary things without proper research!
    During that notable journey, we did get a beautiful arc going for a bit, and the thing went like a …. train.
    BTW, I find that some third rail systems use a pick-up on the side or underneath the rail to cut the contamination problem.
    ‘Alice’

  2. John
    February 13, 2010 17:35

    Is there a way of keeping the third rail above 0 degrees Centigrade, so the ice would not form on it.
    I was thinking they could glue a very long strip heater on the sides of the third rail and use the 750V supply from the third rail to power it.

  3. February 11, 2010 13:51

    A track cleaning train on main lines is an obvious answer just as in years gone by the District Controller would send out some light trains (locomotive plus one coach) for track clearing during the night.
    It could still be done today and cost isn’t really the problem. Today Network Rail keep a tight control over all movements on the track. Local management can no longer take decisions like running an extra train; the decision has to be taken from the top. Today’s railway is micromanaged to a high degree and there is little flexibility.

  4. Bob
    February 11, 2010 13:21

    Most conventional locomotives are Diesel/Electric.
    Diesel power plants running a generator to provide electrical power to electric traction motors. No doubt someone will correct me but I was under the impression that the 3rd rail DC electric locomotives of the 1960s/70s carried a diesel engine for dual redundancy ?
    In line with Kris’s email, I would guess that the engineer who specified the train Alice was on, had to ditch the dual redundant diesel engine on cost grounds due to commercial politics.
    Obviously the driver was an engineer in a former life so hats off to him, but as for the solution, isn’t it an issue for rail maintenance people ? – lets face it, the roads are supposed to be gritted while were all asleep, and you wouldn’t expect your new car to be delivered with a road sweeper, so where was the track cleaning train or does that cost too much as well ?

  5. jcj
    February 11, 2010 13:13

    I think the problem is neurotic trains rather than anything else. Modern ones with control electronics are far more picky about the quality of the electrical supply than older ones with a heap of contactors, relays etc. Paranoia about interference with signalling systems.
    Old trains would just carry on despite the ice on the live rail – a load of arcing to the first set or sets of shoegear would clear enough of it off, particularly if the train has enough shoes that later ones get a reasonable contact.
    It also helps to run trains periodically all day and all night to keep the buildup from ever getting so big in the first place.
    Incidentally one type of 1950s stock still holds the reliability record in the UK – over 100,000 miles per casualty.
    See “Modern Railways” passim.

  6. Simon
    February 11, 2010 11:47

    only just seen this one, but I remember in the late 70′s the trains stopping due to sparks from the pick setting fire to the pick-up support (oil-soaked wood being the insulator) and also motor burn outs due to the intermittent contact causing huge current surges. Not sure how train technology has moved on since then.

  7. Brent Hayhoe
    February 11, 2010 11:43

    The answer, of course, is not a blow torch, but a steam jet. The same way they de-ice planes.
    We should never have left the age of steam!
    BRs
    Brent.

  8. Alan Grant Dominey
    February 11, 2010 11:24

    How about a simple wire brush arrangement ahead of the pick-up – or is that just too obvious . . . . . . .

  9. Kris
    January 22, 2010 17:04

    I imagine the heat from a blowtorch, nearby heating coil, etc. could over time weaken the rail to the point of failure. And the potential legal liability from keeping flammable fuel on board for a blowtorch? Not worth the risk I imagine.
    I would bet that the current solution, while occasionally an inconvenience to passengers, is probably the simplest and least costly for the train manufacturer and rail companies. After one train clears the way, it should be somewhat less likely that the subsequent trains will have less of a problem.
    Your readers, while they sound like very intelligent engineers/problem solvers, would do good to think about cost and who would bear the cost for a more advanced solution. Politics plays a roll, and the manufacturers/rail companies don’t care too much about a few inconvenienced passengers once in a while.

  10. 'Alice'
    January 20, 2010 14:44

    I was thinking of a something to clean the track only at low speed to allow the train to get some momentum.
    And a blow torch sound like it would do the trick, and would not rely on electricity.
    There must be a good reason why these things are not done.
    It can’t just be cost.
    ‘Alice’

  11. Andrew
    January 19, 2010 13:47

    The third-rail pickup is a mechanically very challenging environment (in the UK, DC electric trains can travel up to 70-80mph), and I can’t imagine mechanical scrapers would be easy or robust.
    A powerful blow-torch directed on the track just ahead of the pickup might do the job I suppose, with it’s power adjusted dynamically according to the speed of the train (and conditions)…?
    Overhead 25kV systems are much less prone than third-rail to trouble in cold weather, although they do spark very prettily when condensation is frozen on the wire.

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