"3rd rail no longer feasible"

[Nawdic]

According to the recent edition of Railway Magazine Network Rail no longer feel that 3rd rail is the way to go, so ultimately, Merseyside and the Ex SR region will be OHL'd...

Your oppinions please.

[EXTspotter]

Right now the fact they have electrification means that nothing will happen. The government is wanting to save money by converting non-electrified lines to electrified ones, I am sure that OHLE is cheaper to run than 3rd rail but diesel is probably going to get more and more expensive with crude oil becoming more scarce but its demand growing ever more. In merseyside the distances involved do not require high speeds, so I do not see a problem with leaving it as 3rd rail. The southeast has longer distances but again the longest 3rd rail journeys (London - Weymouth) are still less than 3 hours, hence any OHLE electrification and line improvments would not have a massive improvement in journey times. I believe the government is more likely to electrify other lines like Liverpool - Manchester, London - Bristol...

[JamieLei]

Third rail however has much higher maintenance costs I believe. It's also much more prone to cock-up when there's snow, and other weather badness. The Eurostar engineers couldn't wait to pull the third-rail shoes off the Eurostar sets I believe, because they were such an arse (the shoes, not the engineers).

The Japanese are pretty good at investing vast amounts of money for returns in the future, so there must be some reason why even the crappiest branch lines are overhead-electrified (albeit DC).

[Geo Ghost]

Am I correct in thinking that 3rd rail has a much lower top speed than over-head (excluding HS1 of course).

[GurraJG]

Am I correct in thinking that 3rd rail has a much lower top speed than over-head (excluding HS1 of course).

Theoretically at least, yes.

[Nawdic]

Maximum speed between Redhill Avoiding (Quarry line) and Three Bridges is 100mph, (recently uprated from 90) this report says that trains struggle to get above 80 because of the amoubnt of power being drawn, also due to the amount of other trains on this section

[EXTspotter]

To be fair though for the distances travelled 80 to 90 mph are better than most places around the world. 100mph is possible but as was said before difficult to achieve given certain other factors. Then again with the amount of trains in the area I am sure OHLE would encounter similar problems - look at the Leeds - Skipton line and how 91s can't use it as they drag out too much power, similarly with the well recounted 92s on the Great Eastern Main Line causing EMUs around it to as good as stop.

[JamieLei]

The world speed record for third rail was set by a Class 442 at something like 108mph.

Still we gotta keep things in perspective worldwide. In most countries, it's very rare for non-express on non-purpose-built lines to get above 100mph. The MML top speed is also 100mph I believe, unless someone can correct me.

[broodje]

Why do you have to look world wide? Doesn't the UK have it's own ambitions?
But the main problem with 600volts DC is the amount of under stations (is that the correct term?) you need to keep all trains running. AC lines have a lot less problems with this, this is in fact the reason why the Netherlands is also looking to convert to AC. (instead of the 1500 volts DC it has now). Before someone trows in the ECML argument: Yeah that line was done on the cheap, and now you can see how much it costs in maintenance if you don't properly invest in converting diesel lines to AC lines.

[Nawdic]

The MML top speed is also 100mph I believe, unless someone can correct me.

125 in places, why are HSTs used on it otherwise??!!

[John]

Why do you have to look world wide? Doesn't the UK have it's own ambitions?
But the main problem with 600volts DC is the amount of under stations (is that the correct term?) you need to keep all trains running.

The term is a "substation". It takes a feed off a high voltage AC line, converts it into a train friendly voltage and feeds it into the third rail.

With 600 Volts DC you will struggle to get lots of power to lots of trains (and probably get wonderful voltage drop to make it even harder). Hence why you need lots of substations.

Andel can problem give more light on this - but do the more rural sections have a high voltage AC line (25k or similar) running along side the track to feed the substations?

[Dave]

The MML top speed is also 100mph I believe, unless someone can correct me.

125 in places, why are HSTs used on it otherwise??!!

No it isn't. 110 max on the MML. The MML is very much like the West Coast - full of summits, bendy and rather curvaceous (bit like my missus ) - without tilting trains 125 would be possible on negligible lengths.

110 running was introduced up from 90 in 1983 when the HST was introduced on the line. 110 also between Derby and Sheffield following Operation Princess...

[Geo Ghost]

No it isn't. 110 max on the MML. The MML is very much like the West Coast - full of summits, bendy and rather curvaceous

Indeed so!
That is why the East Coast Mainline was favoured for the Electra Project as the line was straighter and better for running faster trains at the time.

Hmmm, Maybe the ECML should become High-Speed 2

[Ameecher]

Bits of the MML are now good for 125.

As for this comment

Am I correct in thinking that 3rd rail has a much lower top speed than over-head (excluding HS1 of course).

You do realise that HS1 is 25kV overhead right?

And when I saw this I saw it to mean that 750V DC 3rd rail wouldn't be expanded rather than replaced which seems logical, I'd like to see you try and get OHLE through the tunnels under Liverpool and there is just too much in the South East to make it justifiable, surely? I suppose at least most of the rolling stock can have a pantograph bolted on rather than require entire new builds.
Still I don't think this should stop the two islands of non-electrification in the Southern franchise (Ashford-Hastings & Oxted-Uckfield) being electrified.

[EXTspotter]

Those two should have been done years ago. There is no reason for the class 171 to exist, adding cost for maintainance, as well as other associated costs for such a small specialised group of trains, as well as the negatives related to the higher running costs over electric units.

[Geo Ghost]

Am I correct in thinking that 3rd rail has a much lower top speed than over-head (excluding HS1 of course).

You do realise that HS1 is 25kV overhead right?

Yes, I have noticed it quite easily after standing next to it and taking trips on the line. I don't understand where you are going with that, if you could explain it.
I say excluding HS1 since that is obviously going to have a high top-speed than any other railway in Britain so can't be brought into the whole DC vs AC thing when regarding speed in this case.


The down-side with a full upgrade to over-head is the time and cost it will take to build plus having to replace the large majority of existing stock. Not to mention all the delays and problems it would cause to an already heavily crowded area (crowded in terms or rail usage that is as well as number of people using it).

[61653]

Most modern stock would not be difficult to covert- Desiros and Electrostars are both technically dual-voltage machines, and even have a pantograph well in one of the cars of each unit. I think the report is largely aimed at discouraging future extensions of the 3rd rail network (Basingstoke-Salisbury/Exeter for example) and possibly converting existing areas as the equipment becomes life expired. DC systems lose A LOT of energy through heat, hence whilst 100mph+ is possible, on the SW and Brighton mainlines, it's not very efficient. True, many of the UKs overhead electrifications have suffered from under-investment (Maggie's saggy wires on the ECML etc), but 91s are now passed to Skipton, the 1st run taking place in the last few weeks. Of course, most of the 3rd-rail network is slower commuter services, especially the Merseyside system, so the lack of high-speed running is not a problem- it's more a matter of efficiency- 750dc made A LOT of sense in the 40s and 50s as power was cheaper and the trains of the time not so power-hungry- One of the main teething problems with the 3rd generation EMUs was the fact that the onboard systems (aircon, onboard computers etc) drew so much more power from the system than the slam-door stock they replaced. With more modern stock, the shortcomings of the DC system are becoming more apparent when compared with AC.

[teccuk]

The Japanese are pretty good at investing vast amounts of money for returns in the future, so there must be some reason why even the crappiest branch lines are overhead-electrified (albeit DC).

Because as Chris Green and others knew, its better to bite the bullet and take the wires a little bit further than to have diesel diagrams and associated infrastructure hanging about. If you're overheading then you might as well. Hence St Albans abbey branch and why GWML should go to Weston-super-Mare and Swansea and take in the Cardiff commuter routes.

[Dave]

Am I correct in thinking that 3rd rail has a much lower top speed than over-head (excluding HS1 of course).

You do realise that HS1 is 25kV overhead right?

Yes, I have noticed it quite easily after standing next to it and taking trips on the line. I don't understand where you are going with that, if you could explain it.
I say excluding HS1 since that is obviously going to have a high top-speed than any other railway in Britain so can't be brought into the whole DC vs AC thing when regarding speed in this case.

Ah but it looks like you've said that 3rd rail has a lower speed than OHLE, excluding HS1... Suggesting you mean HS1 is 3rd rail and is an exception. Since HS1 has a higher speed than 3rd rail anyway, the brackets were really not necessary haha.

[Ameecher]

Glad it wasn't just me who read it like that.