Why do wires come down so much?

Why do wires come down so much?

Is it an Amtrak maintenance problem? What actually goes wrong that maintenance would fix?

Is it a NJ transit problem related to the pantographs?

Does cold make it worse? Why?

I can't imagine it can't be fixed -- I would be suprised if they had such frequent problems in France or Germany or Switzerland.

Thanks, JS

I belive that this morning's break was because the wire contracted from the cold and the excessive tension broke it. I suspect that most catenary in Europe is constant tension design with counterweights which overcomes the temperature problems.

Ken W2KB wrote:I belive that this morning's break was because the wire contracted from the cold and the excessive tension broke it. I suspect that most catenary in Europe is constant tension design with counterweights which overcomes the temperature problems.

I know they use counterweights in Switzerland.

MetroNorth's New Haven Line uses constant tension catenary, I believe. Much of it is new (within the last decade).

But, they get snags and wire pull-downs too.

Has to be the cold... I mean, it happens in warmer waether too, but I would expect it to happen more during this time of year. Look at how cold it gets over night and then rush hour traffic hits those wires out of nowhere.

old, tired and cold-

Also, I think their age contributes somewhat to catenary problems. Catenary was used in the beginning of the 20th century. This is also a problem in very hot weather (i.e. 100+ degrees for a few consecutive days) when the wires expand and it becomes easy for the pantograph to 'over-extend' and then pull down wires.

The 1930s were not the beginning of the 20th century. PRR put those wires up in the 30s.

That is still 70 years, which can be considered the beginning of the 20th century versus the latter half. Also, the New Haven's old wires (which Metro-North started replacing a year or two ago) go back towards that century's second decade.

pumpers wrote:Why do wires come down so much?

Because Congress isn't told to send money towards it by its constituents, and the voices of the road/auto lobbies are far, far louder than the rail ones. Therefore, Congress will wait until a catastrophic failure before acting. Wire breaks they don't consider to be "catastrophic". Amtrak, who gets funded at a far lower rate per track-mile (and catenary wire-mile) than any commuter railroad in the country, can only make do with what it gets from Washington DC. Nothing wrong with NJT equipement pantographs.

Does cold make it worse? Why?

Yes, and because metal gets brittle in the cold and loses its malleability (i.e. it becomes more like porcelain instead of having the bendable/shapeable quality that you are used to seeing in metal).