Railway Catenary during inclement weather

[Another JohnSParticipant @anotherjohns]

I’m sure the city of Ottawa is not the only rail transit system with overhead catenary, but it seems as if there’s a breakage every month – or recently, with a bit of ice, every day.

What happens in the UK and in Europe?

The line currently is 12.5 km, just shy of 8 miles long, and this morning is the 2nd catenary wire breakage in 3 days.

If I said that it averaged 1 breakage per month, that would be 1 breakage every 2.5km of track per year. Even if we say 6 per year, that’s a breakage every 5km.

Google says the UK has 6,130km – roughly 500 times more catenary. The UK should get about 100 breakages per month, or 3 per day.

Does the UK rail system get 3 catenary system outages per day?

[Charles LamontParticipant @charleslamont71117]

A bit of surfing showed that the Ottowa system is apparently a basket case. China has 160,000 km of railway line, 75% of which is overhead electric. India is 95% electric, Switzerland, Belgium and Luxembourg are almost completely electric. The UK is, as usual, underinvested, at 40%. The majority operate at 25kV AC.

[Howard LewisParticipant @howardlewis46836]

Possibly, the weather in UK is less extreme than in Ottowa.

Also, Britain does seem get more “Wrong kind of snow” that other countries.

So maybe things balance themselves out in various way?

Howard

[Dave HalfordParticipant @davehalford22513]

Just don’t mention the leaves.

[Nigel Graham 2Participant @nigelgraham2]

I am surprised they have all those breakages in Ottowa.

 

The railways in Scandinavia, even most of the Trans-Siberian railway, all use overhead electrics and judging by photographs the mechanical designs of those and as used in the UK are very similar. ‘Cos they use simple components and they work.

Fairly elaborate weights-and-pulleys systems at regular intervals maintain an even tension irrespective of weather. (Siberia has the largest annual temperature range of anywhere in the world.)

The one exception on Network Rail is the set of forlorn, empty* davits along the line between Bristol and Gloucester. These massive steel fabrications are clearly made for rapid installation: the arms hook onto the columns rather like book-shelf brackets that clip into slotted bars. Nevertheless whoever designed them instead of specifying the same, tried, tested and proven designs used on the Northern lines and in Norway, must have thought they were building an overhead cable-car system.

[* Still empty? They were a couple of years ago when I last travelled North.)

…

I have heard of electricity transmission-lines breaking in cold weather and causing grass-fires, in Norway too! A pen-friend living in the affected area told me of this. After an unusually dry Autumn the weather broke with freezing fog that so iced the line in question that the cables snapped from the weight and I suppose also the added tension due to the contraction. The resulting arcing to ground ignited the grass and heather, still tinder-dry, before the circuit-breakers acted.

(The natural droop for a slack line under its own, evenly-distributed weight is a catenary, but if the line is tensioned the stress in it and on its anchorages increases considerably as it straightens.)

…

 

Howard- we don’t get much snow but the “wrong kind” phrase was by a careless journalist trying to report on an engineering matter, so well out most journalists’ depth. Not a railway official.

Dave – Leaves are a genuine problem, and Network Rail has even built special rail-cleaning machines to deal with them.

I’m surprised to see those two comments on an engineering forum!

[Howard LewisParticipant @howardlewis46836]

According to the Inuit, there are are nine kinds of snow, so maybe, one of those might be the one labelled as “wrong” in this country.

Probably the kind that caused the problem was small enough flakes to enter the grilles and short bout something in the control system?

[duncan webster 1Participant @duncanwebster1]

Leaves on the track were much less of a problem when we had steam engines because lineside fires got rid of the trees. Just look at old photos from pre 1960, a lot fewer trees. If Netwok Rail started a campaign of tree felling imagine the uproar

[Nigel Graham 2Participant @nigelgraham2]

Howard –

Yes, the serious rather than the “let’s knock fings wot we can’t understand” reports did explain that was the case. The grilles would stop big fluffy flakes, rain or hail, but not the much rarer precipitation more like very fine hail and often blown horizontally in strong wind.

 

Duncan –

Steam locomotives may also have higher adhesion weights per powered wheel than electric or Diesel ones, so perhaps better at cutting through leaf pulp; but they could still slip to a stand in adverse conditions.

Network Rail is cutting trees back in many places, and there seems little real uproar. Some local protests perhaps. Perhaps most people have finally understood leaves do create genuine problems, and they certainly appreciate trees blown down in a gale or felled by disease can block roads and railways alike. So might be more ready to accept the clearances.

[old martParticipant @oldmart]

Sounds like the wires are not always the best alloys for resisting cold weather, I have no idea whether they are steel or some other metal.

[not done it yetParticipant @notdoneityet]

As the old adage goes”one swallow does not make a summer”.  Quoting one small example and extrapolating to a whole rail network is just plain clickbait, IMO.

I put most of it down to climate change – burning too many fossils over the last few decades, or even a century and a half!  Ftrumph!

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