Why was the newcastle metro created as 1.5kv dc powered not 25kv ?

[AHBD]

I wondered why was the newcastle metro was created as 1.5kv dc powered not 25kv , when it was created from old heavy rail routes when 25kv ac had become standard?

Was it to allow regenerative braking? Cheaper installation / stock ?

How thick does a cable for at 1.5k have to b

 

[HSTEd]

The system was more or less bought off the shelf using German equipment, and the Germans weren't using 25kV at all at the time.

Lower voltage electrification is also cheap on low power demand lines like a comparatively low intensity metro.

If the original third rail equipment hadn't been run into the ground you may have ended up with something much closer to Merseyrail, it's contemporary.

 

[snowball]

On a system with frequent stops, DC saves carting transformers around.

Did they have in mind from the start the possibility of street running extensions?

 

[swt_passenger]

As said they bought fairly standard DC units, but when you get into the detailed description of the traction system they are actually using two 750V motors and associated control gear all connected in series. So they probably could have been ordered to work off a 750V supply relatively easily. But if using overhead collection that would result in a doubling of current, and larger contact wires etc.

 

[AHBD]

Thanks. Would it make any more sense for it to be 25kv in the future now that it will share 25kv lines using new dual voltage stock ie when 1.5kv wiring needs replaced?

 

[hexagon789]

I wondered why was the newcastle metro was created as 1.5kv dc powered not 25kv , when it was created from old heavy rail routes when 25kv ac had become standard?

Was it to allow regenerative braking? Cheaper installation / stock ?

How thick does a cable for at 1.5k have to b

Energy costs.

Of the various proposals submitted by manufacturers - Permanent Series 750V motors powered from 1.5.kV overhead won the electricity consumption argument.

25kV was offered in the bids, but was deemed excessive for the requirements.

Thanks. Would it make any more sense for it to be 25kv in the future now that it will share 25kv lines using new dual voltage stock ie when 1.5kv wiring needs replaced?

I believe any further extensions will be 25kV, plus the shared section with Network Rail is to be converted, necessitating dual-voltage stock.

I don't believe the 555s have this capability surprisingly, unless I misses it?

 

[ac6000cw]

I believe any further extensions will be 25kV, plus the shared section with Network Rail is to be converted, necessitating dual-voltage stock.

I don't believe the 555s have this capability surprisingly, unless I misses it?

They don't have 25kV capability, but they do have provision for adding larger traction batteries (they have a small one for 'emergency' use as standard), so in appears the intention is that at least some extensions will be battery powered.

This is a quote from the Stadler data sheet:

The units are prepared for the integration of an energy storage system, allowing to serve potential extension lines added to the network in the near future.

 

[AHBD]

.....dual-voltage stock.

I don't believe the 555s have this capability surprisingly, unless I misses it?

It appears they dropped the 25kv voltage mode due to axle loading if all 3 proposed modes of 1kv5 , 25kv or battery where included which is interesting given the weight of batteries.. So I presume they will run on battery power under 25kv lines.

Modern railways metro

 

[ac6000cw]

So I presume they will run on battery power under 25kv lines.

That was my take on the situation too. How long is the shared (potentially 25kV in the future) Network Rail section to Sunderland?

 

[pdeaves]

How long is the shared (potentially 25kV in the future) Network Rail section to Sunderland?

Approx 9 miles, I believe.

 

[hexagon789]

They don't have 25kV capability, but they do have provision for adding larger traction batteries (they have a small one for 'emergency' use as standard), so in appears the intention is that at least some extensions will be battery powered.

This is a quote from the Stadler data sheet:

I noticed the mention of brake recuperation to storage batteries, but not how useful the stored energy would be (ie just shunting or whether off-wire running was feasible).

It appears they dropped the 25kv voltage mode due to axle loading if all 3 proposed modes of 1kv5 , 25kv or battery where included which is interesting given the weight of batteries.. So I presume they will run on battery power under 25kv lines.

Modern railways metro

I did wonder, given dual voltage capability was previously mentioned in the new stock procurement

 

[DustyBin]

I once read (possibly on this forum!) that the tunnels would have had to have been built to a larger diameter to accommodate 25kv. I think it was to do with proximity of the cables to the surrounding infrastructure. This may not be true, it's just what I remember reading!

 

[HSTEd]

I would be incredibly surprised if 25kV ever reaches Sunderland.

I'd argue dual voltage NR units are far more likely if electric mainline trains ever do go to Sunderland

 

[SeanG]

I would be incredibly surprised if 25kV ever reaches Sunderland.

I'd argue dual voltage NR units are far more likely if electric mainline trains ever do go to Sunderland

Or heavy rail units using battery from Pelaw - Sunderland

 

[edwin_m]

It was certainly pointed out when it first opened, that the Metro overhead wires were run under many existing bridges. Electrical clearance may play a part, but it's at least partly down to the lower roofline of the Metrocars compared with standard trains. The original Metrocars don't have regenerative braking so that couldn't have been a reason. I suggest the main one was avoiding having to put a transformer on each train.

 

[Tetchytyke]

The Metro was never meant to be a heavy rail system. It was much more akin to a tram system, to the extent that Metro-Cammell actually marketed the Metrocars as "supertram". And you don't get trams with 25kV overhead wires.

It'll only ever be an issue if Sunderland-Pelaw requires electrification for heavy rail, which I wouldn't see happening at least for another generation, if ever.

 

[Vespa]

The Metro was never meant to be a heavy rail system. It was much more akin to a tram system, to the extent that Metro-Cammell actually marketed the Metrocars as "supertram". And you don't get trams with 25kV overhead wires.

You do now with Sheffield TOPS numbered dual voltage tram to Rotherham on NR tracks.

 

[miklcct]

1.5kV DC is more suitable for a tunnelled metro operation because it's cheaper to build tunnels for 1.5kV DC operation due to the clearance requirement.

 

[D365]

You do now with Sheffield TOPS numbered dual voltage tram to Rotherham on NR tracks.

25kV capable - the Rotherham electrification is currently operated at 750Vdc.

 

[43096]

25kV capable - the Rotherham electrification is currently operated at 750Vdc.

In which case I’ll throw in the new Cardiff Valleys sets, which are tram-trains with 25kV capability.

 

[DanNCL]

You do now with Sheffield TOPS numbered dual voltage tram to Rotherham on NR tracks.

25kV capable - the Rotherham electrification is currently operated at 750Vdc.

In which case I’ll throw in the new Cardiff Valleys sets, which are tram-trains with 25kV capability.

The Sheffield tram-trains have 25kV capability, but the wires to Rotherham are 750v DC like the rest of Supertram so the 25kV capability of the tram-trains is unused.

The South Wales tram-trains will be powered by 25kV and won't have any DC capability. All running away from 25kV will be done with batteries.

 

[DustyBin]

The Metro was never meant to be a heavy rail system. It was much more akin to a tram system, to the extent that Metro-Cammell actually marketed the Metrocars as "supertram". And you don't get trams with 25kV overhead wires.

It'll only ever be an issue if Sunderland-Pelaw requires electrification for heavy rail, which I wouldn't see happening at least for another generation, if ever.

The current fleet is based an a German tram design (below solebar at least) but the system itself has very little in common with a tramway. It's more of a suburban rail network, similar to U-Bahn or possibly S-Bahn (there's considerable disagreement over which!).

 

[Tetchytyke]

the system itself has very little in common with a tramway. It's more of a suburban rail network, similar to U-Bahn or possibly S-Bahn (there's considerable disagreement over which!)

It's a weird mishmash, really. It's certainly not an S-Bahn- Merseyrail is the best UK example of that. The trains are lightweight and the stations are very basic, there's really very little difference between Metrolink's off-street sections and Metro. Even the underground sections are closer in feel to the Brussels pre-Metro than a U-bahn or even Merseyrail.

The new trains, which are a bit more heavy duty, will definitely move it more towards a U-bahn though.

 

[DustyBin]

It's a weird mishmash, really. It's certainly not an S-Bahn- Merseyrail is the best UK example of that. The trains are lightweight and the stations are very basic, there's really very little difference between Metrolink's off-street sections and Metro. Even the underground sections are closer in feel to the Brussels pre-Metro than a U-bahn or even Merseyrail.

The new trains, which are a bit more heavy duty, will definitely move it more towards a U-bahn though.

I agree, it’s definitely a mishmash and doesn’t fit neatly into a category. That’s a good point re the new trains though, they’re decidedly U-Bahnesque.

 

[SeanG]

I agree, it’s definitely a mishmash and doesn’t fit neatly into a category. That’s a good point re the new trains though, they’re decidedly U-Bahnesque.

And indeed virtually the same as those used on the Berlin U-Bahn

 

[Recessio]

Only in Britain could we end up with electric trains running on batteries on electrified tracks, christ almighty...

 

[D365]

And indeed virtually the same as those used on the Berlin U-Bahn

The new T&W trains are siblings of the Class 777, are they not? (descended from Berlin as you say)

 

[hacman]

The new T&W trains are siblings of the Class 777, are they not? (descended from Berlin as you say)

They're quite different from the Berlin units (Berlin have non-articulated cars for a start).

They're siblings in as much as they use similar technologies and components, but then again that would be the case for most of the products that Stadler offer across multiple categories.

https://www.stadlerrail.com/media/pdf/tbvg0713e.pdf - BVG units
https://www.stadlerrail.com/media/pdf/mmer0420e.pdf - Merseyrail 777s
https://www.stadlerrail.com/media/pdf/mmer0420e.pdf - Nexus 555s

Only in Britain could we end up with electric trains running on batteries on electrified tracks, christ almighty...

I think we're a long way off from that being the case here on Tyneside. And if it were to become a prospect, we could just as easily order a sub-fleet with 25kv capability, or even add a power-pack module into the existing consists as Stadler have done for other customers.

 

[Haywain]

Only in Britain could we end up with electric trains running on batteries on electrified tracks, christ almighty...

We don't actually have that. Instead we have electric trains running on diesel on fully compatible electrified tracks ...

 

[61653 HTAFC]

Only in Britain could we end up with electric trains running on batteries on electrified tracks, christ almighty...

I've long held the position that our insistence on putting all our eggs in the battery basket will come back to bite us on the rear end. I've yet to hear anything to avail me of this.