Tyne and Wear Metro - Power?

[Chrisorganist26]

Hi All,

I was up in Newcastle last weekend and so took the opportunity to ride on as much of the metro as I could.

I was wondering why overhead cable was orignally chosen to supply the power rather than a 3rd rail system given that none of the system runs on street. The system leans more towards the London underground (especially in the city) than a light rail sytem. Surely 3rd rail would have been a cheaper option.

Anyone know the reasons behind this?


Every blessing,



Chris.

 

[O L Leigh]

Welcome, Chris.

1500V DC is a bit much for a 3rd rail. Much easier, safer and cheaper to have it up in the air where it can't get away.

one TN

 

[1D53]

3rd rail is now prohibited from new installations on the National network from what I recall.

Plus 142's arent allowed on third rail in normal conditions hence wouldnt mix between Heworth - Sunderland.

 

[eezypeazy]

Before construction of the Tyneside (as it was then) Metro began, there was considerable discussion about the type of electrification to be employed. 3rd rail was indeed "frowned upon", in that no new installations were to be approved. At one stage, operation of Metro was going to be undertaken by British Rail, but they were apparently insisting that the system be built to their OHLE standards - ie., 25Kv AC! This would have resulted in the bore of the tunnels through Newcastle and Gateshead having to be much larger, to provide adequate electrical insulation, and the rolling stock would require additional (and heavier) equipment. (BR were also insisting on 4 aspect signalling, which, on a system designed for a two and a half minute headway and top speed of 50mph, would have been extremely expensive and definitely "over the top" - you would always be driving on yellow aspects through the tunnels! PTE engineers, on the other hand, wanted tramway-style "drive on sight" outside of tunnels and junctions. I believe the HSE/Railway Inspectorate insisted on the two/three aspect compromise). After much discussion between PTE, British Rail, and the unions, the PTE decided that BR's demands were impractical and would have added huge additional (and unnecessary) cost, and that they would operate the system themselves, promising that it would employ otherwise redundant BR and bus men.

Additionally, the system was designed with the potential for street running. At St. James, the tunnels continue a short distance beyond the platform ends, and can (relatively) easily be extended to the surface to gain the streets of the west end of Newcastle.

So that's why we ended up with 1500v dc.

Regards

eezypeazy

 

[gordonthemoron]

The north tyneside loop, which was replaced by the Metro, was third rail from between the wars until the 60's I believe.

 

[Metroland]

Indeed it was. in fact the first 3rd rail electic trains were in Tyneside, not on the southern.

The main disadvantage of third rail is ice on conductor rails and frequent feeder stations, overhead is usually a good system if you don't have to raise bridges.

With 1500v DC, the clearances allowed are much tighter than 25kv, which is a French system, designed for the larger loading gauge but that system does allow more juice to be piped to the trains. That's not important with a light weight low speed metro system, hence why 1500v DC was chosen.

 

[Mojo]

Traditional third rail is not now allowed for any new installations, except approved extensions, but a protected low-level rail *is* allwowed - see DLR for example.

 

[metroman]

Hi,
I have actually just joined this forum, and I actually work on the Tyne and Wear Metro System. Yes, 3rd rail power is now not allowed. The Sunderland Extension was actually built to Network Rail specs, but obviously they had to keep to 1500 vdc as the power. I work on Station Services, Lifts and Escalators etc. If anyone needs to know anything about the system I am that person to answer any questions.
Martin

 

[robertclark125]

One issue with third rail as well was that the type of cars to be used would prevent third rail. Many people think that the walkways in the tunnels prevented 3rd rail. This is not the case, as the jubilee line extension has them, and has 4th rail power.