Railway electrification - ongoing (sometimes very!) technical discussion

[whole diary]

[stuving]

Nuclear power stations in the UK^▸ (United Kingdom) are normally sited close to the sea or in one case to a large lake to provide a lot of cooling water.  The one by the lake did end up heating up the lake more than was desired sometimes.

I know they have inland nuclear stations on the contents I assume this is possible because they have bigger rivers.

Nuclear has nothing to do with it, though size (power) does. All thermal power stations need somewhere to reject heat at as low a temperature as possible. And all the big ones on rivers will, in summer, run up against the limit placed on them for the maximum downstream river temperature. So they have to dump some power somewhere else, or turn the wick down. Many will have cooling towers to help out at such times, though usually too small to take the full power. I think some air cooling may be used too.

Fortunately peak demand is lower in summer - though as you go south (or the equivalent effect is produced by global warming), and as we install more air conditioning, this may cease to be true.

[Bmblbzzz]

Nuclear power stations in the UK^▸ (United Kingdom) are normally sited close to the sea or in one case to a large lake to provide a lot of cooling water.  The one by the lake did end up heating up the lake more than was desired sometimes.

I know they have inland nuclear stations on the contents I assume this is possible because they have bigger rivers.

Nuclear has nothing to do with it, though size (power) does. All thermal power stations need somewhere to reject heat at as low a temperature as possible. And all the big ones on rivers will, in summer, run up against the limit placed on them for the maximum downstream river temperature. So they have to dump some power somewhere else, or turn the wick down. Many will have cooling towers to help out at such times, though usually too small to take the full power. I think some air cooling may be used too.

Fortunately peak demand is lower in summer - though as you go south (or the equivalent effect is produced by global warming), and as we install more air conditioning, this may cease to be true.

You don't have to go south; electricity demand in Poland (which does have hotter summers than Britain) is highest in summer, and it's mainly down to air conditioning. Also because electricity is very rarely used for heating there (it's mainly coal or oil).

[JayMac]

I got scared by a little spark when disconnecting the negative terminal on a car battery earlier today. Classic banging of head on bonnet underside and dropped spanner through engine bay.

So I think I'll stay well away from 25kV AC. Kudos to those who work with it day in, day out.

[Western Pathfinder]

I got scared by a little spark when disconnecting the negative terminal on a car battery earlier today. Classic banging of head on bonnet underside and dropped spanner through engine bay.

So I think I'll stay well away from 25kV AC. Kudos to those who work with it day in, day out.

A word to the wise Allways disconnect the Earth Lead first  and Reconnect it Last
Negative - terminal = Earth 

[JayMac]

Yes, well aware it's negative first off, last on, on nearly all cars. As I was doing. Small sparks are to be expected apparently. I just wasn't expecting.

I was working on electrics - the aerial base needed replacing - requiring removal of courtesy light assembly. So not fully removing battery.

[bobm]

I learned my lesson with a 415v 3 phase supply - switchgear for generator failed and when the external supply came back the generator was still trying to maintain the juice.   They didn't agree!

[lordgoata]

When I was on work experience at a computer maintenance company, we were stripping down some monitors (old CRT^‡(resolve) types) and the chap explaining it to me was discharging the tube by shoving a screwdriver into some part of it, holding another on the ground and touching the two together. Just as I was about to do it, he said to me "if you do it wrong, it won't be the shock you remember, it will be the smell of the burning flesh" .... not what I wanted to hear! (and now I feel really old thinking back to that!).

[chrisr_75]

I got scared by a little spark when disconnecting the negative terminal on a car battery earlier today. Classic banging of head on bonnet underside and dropped spanner through engine bay.

So I think I'll stay well away from 25kV AC. Kudos to those who work with it day in, day out.

A word to the wise Allways disconnect the Earth Lead first  and Reconnect it Last
Negative - terminal = Earth 

There's still plenty of positive earth cars knocking about....granted not very common now but nevertheless not unheard of

[paul7575]

Another top tip when working on car (or any similar) battery terminals is to always remove any rings and/or metal watch straps etc while working. 

While you're being extremely careful with any tools that you are using, rings and watch straps are just the sort of things that accidentally make good conductors, and they'll get pretty warm while doing so...

Paul

[TonyK]

And anyone carrying an unwrapped 9V battery and a 10p coin in his pocket is unlikely to do it twice. I certainly won't!

[chrisr_75]

Another top tip when working on car (or any similar) battery terminals is to always remove any rings and/or metal watch straps etc while working. 

While you're being extremely careful with any tools that you are using, rings and watch straps are just the sort of things that accidentally make good conductors, and they'll get pretty warm while doing so...

Paul

I've also discovered that many modern cars actually have live terminals on alternators with engine stopped. I discovered this from a significant flurry of sparks from a (subsequently dropped) spanner as I was undoing the terminal nuts...!!

Another top tip is to connect a battery charger or external starter pack before turning on at the wall (same also goes for jump leads - connect up before starting the 'donor' vehicle) - plenty people have been badly burnt (acid) by causing batteries to explode from the sparks generated by connecting an energised charger or starter pack.

[ChrisB]

And anyone carrying an unwrapped 9V battery and a 10p coin in his pocket is unlikely to do it twice. I certainly won't!

As a teen, there were some who put both terminals of a 9v battery on their tongue....

[TonyK]

I've also discovered that many modern cars actually have live terminals on alternators with engine stopped. I discovered this from a significant flurry of sparks from a (subsequently dropped) spanner as I was undoing the terminal nuts...!!

And the starter motor, and anything else that is attached to the electrical system and has exposed terminals.

[Fourbee]

I agree with SandTEngineer there has been a massive skill fade within NR^» (Network Rail - home page), some by natural wastage but a large part of it was restructuring of the Projects part of NR lots of very experienced engineers, project managers, commercial mangers made redundant with a heavy reliance being placed on suppliers "knowing what they are doing" and yes they do bt NR has lost a lot of its "informed buyer" knowledge.

At the time when NatWest/RBS had their major batch payments problem (the one that went on for weeks not the other hiccups) there were some allegations that due to outsourcing, the knowledge previously built up had drained away (not everything is documented of course). I suppose there is a real distinction between skill and knowledge (i.e. I could theoretically drive in central london and get you where you want using a GPS/map, but having the knowledge in your head is superior IMO^▸ (in my opinion)).

[ellendune]

If it wants to do more it must prove itself by lower costs and timely progress. It must learn real engineering - solving problems within a budget and vigorously contesting other impediments that bystanders such as ORR^» (Office of Rail and Road formerly Office of Rail Regulation - about) and DfT^» (Department for Transport - about) throw up.

And to do that it must have a steady (if slow) programme of work.  Rushed programmes to meet politicians grandiose and plans announced to win votes will never do that. 

That will allow work to be properly phased with other work (e.g. Bristol East Junction and Temple Meads Works) to minimise electrification costs. 

Wires only need to follow the traffic, i.e. where EMU^▸ (Electric Multiple Unit)'s are needed or where the bi-modes will struggle. I suggest that in our area that means to Oxford (without an unaffordable new station)

I hope your reference to Oxford's unaffordable new station only relates to iconic buildings, rather than the much needed capacity improvements.

The quickest way to increase electric mileage is to make the Voyagers bi-mode.

Even better complete the electrification of some routes and cascade the existing bi-modes that can then be replaced by electric only trains.