Electrification Voltage Types

[MidnightFlyer]

Couldn't think of a different title - sorry!

I was reading up that the old Bury-Man Vic BR line (now the Metrolink) had a different AC electrification type than elsewhere on the network (can someone confirm that for me?)

After reading that, I was wondering, within the two chief electrification types (AC overheads and DC third), how many different voltages are there, and where are they used?

I know the WCML is 25,000V and third rail is 750V, and that West Yorkshire must have different powers in the overheads, as a 225 would drain all the power from the area when running over it -hence Skipton-Kings Cross trains being HSTs!

Thanks in advance, guys!

 

[WatcherZero]

1200v DC side contact 3rd rail.
Here you go, a 1983 photo of a class 504 on the Bury line.

Couple of other light rail electrifications you can add, Blackpools 600v DC overhead, All the other tram networks are 750v DC OHLE, Tyne and Wear Metro is 1500v DC OHLE

 

[MidnightFlyer]

Thanks for the info and photo.

Are all mainline using OHLE (ECML, WCML etc) 25,000V and are areas like northern Thameslink, Hitchin-Kings Lynn etc weaker versions of these?

Also, what power will the Northern electrification be?

 

[mumrar]

I know the WCML is 25,000V and third rail is 750V, and that West Yorkshire must have different powers in the overheads, as a 225 would drain all the power from the area when running over it -hence Skipton-Kings Cross trains being HSTs!

The ECML is 25kV also, that is the only overhead anywhere in the UK railway network. Don't forget that Class 92s have far more draw than a 91 as well, and are predominantly WCML machines.

 

[First class]

Merseyrail has a mixture of 650v and 750v DC.

Isn't the tyne metro overhead DC?

 

[swt_passenger]

The SR third rail system is nominally 750V DC, but around that figure there are fairly large variations. For example, one of Network Rail's current projects in south London is to completely separate supplies to LU and NR, because a few odd bits of SW London are running at 660V for LU's benefit. Stuff like the District shared sections to Richmond and Wimbledon, and the whole Waterloo & City line, which although functionally separate still uses SR power.

(Probably something similar on the DC lines as well.)

Once all the south London systems are completely separate, I think the intention is to wind the NR side up to a higher working voltage, maybe 800V?, but it'll still be referred to as a 750V system as far as I can see...

 

[WatcherZero]

All mainline OHLE is 25kv yes, issues arise as some units draw more power than others and some areas may have a large amount of traffic the area needs sufficent transformer capacity to keep up with demand or you will either have sections of undervoltage or overtaxed transformers may burn out faster than normal.

 

[DaveNewcastle]

Some of us tried to answer an almost identical question on here last week:
http://www.railforums.co.uk/showthread.php?t=37829.
There might be some more useful help there.
--- old post above --- --- new post below ---

. . . . West Yorkshire must have different powers in the overheads, as a 225 would drain all the power from the area when running over it -hence Skipton-Kings Cross trains being HSTs!

I wonder if you may be confusing the available current from the distribution network and the line-side transformers with the choice of voltage and pick-up system.

"Draining power" would indicate a lack of available current (which in turn is likely to lead to a voltage drop). This can arise in systems of any voltage when the demand exceeds the designed capacity.

 

[jopsuk]

This is perhaps enlightening- shows quite what voltage "750V" DC etc can actually be in this country.

The will tell you about every system that has ever been used in Great Britain. There's a lot...

 

[TGV]

There's also the AC supply to HS1 which is autotransformer 25kV - which is a 50kV supply with effectively a "centre tapping" to give 2 wires - (the contact wire and the return wire which is the one you can see on HS1 that's on the non-rail side of the OLE masts held with insulators) at 25kV but in opposite phases, with the rail being the "0" or earth.

I mean, it's still 25kV as far as the train is concerned, but from an infrastructure point of view, it's very different (and damn clever).

 

[jopsuk]

I was just reading about that (through a link from the second article I posted)- apparently there's some of that installed on the WCML too. Makes no difference to the rolling stock, as you say- it's about extending range and even making the power supply more resilient/smoother etc.

 

[WatcherZero]

It was my understanding all the 25kv would be naturally replaced with autotransformer, cheaper to maintain.

 

[Lampshade]

I know the WCML is 25,000V and third rail is 750V, and that West Yorkshire must have different powers in the overheads, as a 225 would drain all the power from the area when running over it -hence Skipton-Kings Cross trains being HSTs!

Thanks in advance, guys!

It's still 25kV, the Skipton Line doesn't have its own supply so the current there isn't sufficent to power a Mk4 set.

 

[Hydro]

A lot of the 750v DC infrastructure on the SWML was upgraded when the Desiros were introduced, and apparently is more on the side of 850v now.

 

[142094]

Isn't the tyne metro overhead DC?

1500 V DC. Only one in the UK currently, of course thw Woodhead was the same when it was open.