Alternative To Third Rail?

[Doomotron]

Third rail is outdated, and will need replacing or upgrading at some point. The optimum choice would be 25KV OHE but there is obviously problems with bridges, tunnels, and post importantly at Ashford International and Dollands Moor, because the OHE already there is higher than the normal UK height.

What options are there the upgrading or replacement of the third rail? Or should it be kept as normal?

 

[Legolash2o]

I'm not really a fan of electrification for various reasons (cost and problems it brings) but I prefer newer technologies such as battery, bi-mode or hydrogen.

 

[hwl]

Third rail is outdated, and will need replacing or upgrading at some point. The optimum choice would be 25KV OHE but there is obviously problems with bridges, tunnels, and post importantly at Ashford International and Dollands Moor, because the OHE already there is higher than the normal UK height.

What options are there the upgrading or replacement of the third rail? Or should it be kept as normal?

Heavier section 3rd rail for lower losses. Ditto heavier section running rail.
Use long lengths / welded 3rd rail.
Upping the voltage to 750V in the old 650/660 areas.
Replacing traditional impedance bonds /track circuit equipment with audio frequency ones or axle counters.
Replace track paralleling huts with more substations.
More substations
Larger transformer /rectifiers
Reduced impedance feeds designs for lower losses
Enabling regenerative braking
...
Put the train on diet e.g. SWR 701 with inside frame bogie to reduce power requirements.

 

[hwl]

I'm not really a fan of electrification for various reasons (cost and problems it brings) but I prefer newer technologies such as battery, bi-mode or hydrogen.

3rd rail is still significantly greener and efficient than Hydrogen or battery (or Bi-mode)

 

[AM9]

... and post importantly at Ashford International and Dollands Moor, because the OHE already there is higher than the normal UK height. ...

I think that you'll find that the entire HS1 line's OLE is within the normal range of UK domestic train's pantographs. Although the class 395s have French design pantographs, they conform to UK loading gauges.
The Folkestone terminal and through the tunnel is higher to accommodate the higher Shuttle vehicles. Even the tunnel's contact wire was accessible by class 319s simply by adjusting the over height settings.

 

[AM9]

3rd rail is still significantly greener and efficient than Hydrogen or battery (or Bi-mode)

But it has been ruled out on safety grounds for future extensions. Beefing it up as is being suggested would probably rule it out on through life and energy grounds as well.

 

[MarkyT]

I suggest discontinuous 25kV, as proposed for Cardiff Valleys. Difficult bridges, station canopies and tunnels not wired (or only as neutral sections to avoid having to pan down) and all trains equipped with sufficient storage or engines (this term to include fuel cell technology) to be able to get through AND START within gaps and reach next station in case of supply failure (including 'hotel' power).

 

[grumpyoldman01]

But it has been ruled out on safety grounds for future extensions. Beefing it up as is being suggested would probably rule it out on through life and energy grounds as well.

I appreciate there was a lengthy article on this in the April 'Modern Railways', but surely there must be a mechanism to allow some extensions to existing 3rd rail networks? Otherwise, how are TfL managing to expand the tube network?

As well as filling in the remaining gaps on the old Southern Region, there have been proposals over time to expand the Merseyrail network; would such extensions HAVE to be overhead?

 

[MarkyT]

I appreciate there was a lengthy article on this in the April 'Modern Railways', but surely there must be a mechanism to allow some extensions to existing 3rd rail networks? Otherwise, how are TfL managing to expand the tube network?

As well as filling in the remaining gaps on the old Southern Region, there have been proposals over time to expand the Merseyrail network; would such extensions HAVE to be overhead?

Or on board storage. 'Minor' extensions are permitted but it's difficult to know how far exactly that could be interpreted. A new platform, siding, additional running line or a junction chord is almost certainly OK. A fully segregated railway with no easy means of ingress like a metro might perhaps be allowed. Also technology might be employed to only liven a section when a train is present directly above but that means a lot of separate sections and automated switching complexity. Bottom contact with safety covers top and sides as per DLR might be employed but I can't see how a single train could have pickup shoes for that as well as legacy top contact unless they were retracting devices which again would add complexity and failure potential.

 

[Doomotron]

I think that you'll find that the entire HS1 line's OLE is within the normal range of UK domestic train's pantographs. Although the class 395s have French design pantographs, they conform to UK loading gauges.
The Folkestone terminal and through the tunnel is higher to accommodate the higher Shuttle vehicles. Even the tunnel's contact wire was accessible by class 319s simply by adjusting the over height settings.

Not what I meant. At Ashford International and Dollands Moor, there is already OHE, but it's at a UIC-gauge height. It is higher than British OHE. This is fine for trains on its own, but if we extended the British OHE system to those places, we'd have them at different heights.

 

[Bald Rick]

Battery hybrids are the answer. Various ROSCOs are actively looking into this now, and you can expect demonstration units within a couple of years, and possibly fleet introduction within five.

A few tonnes of batteries on a typical four car unit would be enough to keep it going off the juice for half an hour or so at full power. And 3rd Rail EMUs rarely need to be at full power continuously for 30 minutes, so in reality it’s more like an hour off the juice. Certainly enough for 50 miles, probably more.

 

[Bald Rick]

Not what I meant. At Ashford International and Dollands Moor, there is already OHE, but it's at a UIC-gauge height. It is higher than British OHE. This is fine for trains on its own, but if we extended the British OHE system to those places, we'd have them at different heights.

No we wouldn’t, we’d just match the heights at the transition. Easy!

 

[yorksrob]

But it has been ruled out on safety grounds for future extensions. Beefing it up as is being suggested would probably rule it out on through life and energy grounds as well.

The previous standard of enabling limited extensions/infills to the existing system would be a sensible one to adopt.

 

[yorksrob]

Or on board storage. 'Minor' extensions are permitted but it's difficult to know how far exactly that could be interpreted. A new platform, siding, additional running line or a junction chord is almost certainly OK. A fully segregated railway with no easy means of ingress like a metro might perhaps be allowed. Also technology might be employed to only liven a section when a train is present directly above but that means a lot of separate sections and automated switching complexity. Bottom contact with safety covers top and sides as per DLR might be employed but I can't see how a single train could have pickup shoes for that as well as legacy top contact unless they were retracting devices which again would add complexity and failure potential.

If the line is a branch line with third rail electrification at the end, that should be allowed. Similarly, if the route has third rail electrification at each end, that should also be allowed.

 

[apk55]

The maximum height of of overhead in the UK is determined by clearance at level crossings. Since road vehicles can be up to 4.3M high then allowing for a generous safety margin you ar looking at well over 5M. The same requirement would apply on the continent for UIC standard overhead so there would be height variation there as well. Only on high speed lines where there is no level crossing is constant height overhead used.

 

[Tio Terry]

Not what I meant. At Ashford International and Dollands Moor, there is already OHE, but it's at a UIC-gauge height. It is higher than British OHE. This is fine for trains on its own, but if we extended the British OHE system to those places, we'd have them at different heights.

All new OHEL within the UK is required to meet the Technical Specification for Interoperability (TSI) - Energy. This determines the height of the OHEL. If you want to deviate from that you need to produce a Risk Assessment showing that you have applied mitigation measures such that the finished installation is no less safe than a fully compliant system. In short, all new OHEL electrification will be what you call UIC compliant.

 

[hwl]

But it has been ruled out on safety grounds for future extensions. Beefing it up as is being suggested would probably rule it out on through life and energy grounds as well.

The OP was talking about it needing replacing and or upgrading and I was responding to that bit of the post...

 

[squizzler]

Inductive energy pickup might be an alternative. This thread deals with research done by the German Aerospace Labs (DLR) for a continuous system proposed for their high speed train project.

 

[Ken H]

Battery hybrids are the answer. Various ROSCOs are actively looking into this now, and you can expect demonstration units within a couple of years, and possibly fleet introduction within five.

A few tonnes of batteries on a typical four car unit would be enough to keep it going off the juice for half an hour or so at full power. And 3rd Rail EMUs rarely need to be at full power continuously for 30 minutes, so in reality it’s more like an hour off the juice. Certainly enough for 50 miles, probably more.

Would that work for Uckfield?

 

[RichJF]

Would that work for Uckfield?

Could the 379s be fitted with both 3rd rail & battery & utilised for this?
It would work off peak if they could work with 377s on Oxted line splitters.

Would you need to put a short section of 3rd rail at Uckfield to charge the units while they await their turnaround to London?
If it would work on Uckfield then Marshlink could go the same way!

 

[hwl]

Inductive energy pickup might be an alternative. This thread deals with research done by the German Aerospace Labs (DLR) for a continuous system proposed for their high speed train project.

How much more expensive than 3rd rail?

 

[hwl]

Could the 379s be fitted with both 3rd rail & battery & utilised for this?
It would work off peak if they could work with 377s on Oxted line splitters.

Would you need to put a short section of 3rd rail at Uckfield to charge the units while they await their turnaround to London?
If it would work on Uckfield then Marshlink could go the same way!

GTR have been pondering a trial for MarshLink, haven't heard anything lately.

 

[AM9]

Not what I meant. At Ashford International and Dollands Moor, there is already OHE, but it's at a UIC-gauge height. It is higher than British OHE. This is fine for trains on its own, but if we extended the British OHE system to those places, we'd have them at different heights.

In the UK, mainline trains using OLE are designed to cope with conductor wire heights at a nominal 4.7m and without modification, 5.6m for level crossings. There are some levle crossings on 'high load (road) routes where the conductor wire is at 6.75m, which generally requires adjustment to the height setting switches. It is unlikely that a UK domestic passenger train would enter either Dollands Moor or the Folkestone terminal, but as I posted earlier, two standard class 319 EMUs were taken through the Channel Tunnel with it's 6.3m high conductor and they only required height settings to be adjusted. The class 395s could go beyond Ashford if required as they have the same pantograph type as the UK loading gauge class 373s Eurostar stock, which can travel throughout France on the 25kV network there.
As Tio Terry says, with new UK OLE meeting the TSI, the reach of trains designed to run under it isn't an issue even on the CTRL.

 

[Mikey C]

Could the 379s be fitted with both 3rd rail & battery & utilised for this?
It would work off peak if they could work with 377s on Oxted line splitters.

Would you need to put a short section of 3rd rail at Uckfield to charge the units while they await their turnaround to London?
If it would work on Uckfield then Marshlink could go the same way!

It would probably work as a cheap fix for lines like Uckfield, but going back to the original question there's no way the 3rd rail network in the South East will be eliminated when you consider the massive cost and time overruns we've seen on recent electrification programmes.

From a safety point of view ironically lines like Uckfield would be amongst the safest to run with third rail as so few people live next to it when compared to the lines which run though busy parts of London

 

[td97]

Some current materials research I'm aware of concerns using the train body structure as a super-capacitor, which could be used to the same effect as a battery for short stints without OLE, e.g. tunnels, but without the added mass of the battery.

 

[edwin_m]

Some current materials research I'm aware of concerns using the train body structure as a super-capacitor, which could be used to the same effect as a battery for short stints without OLE, e.g. tunnels, but without the added mass of the battery.

There are also some ideas about structural batteries.

 

[61653 HTAFC]

Would that work for Uckfield?

IIRC one of the issues with Uckfield is the lack of a suitable high-voltage grid line in the area to feed any electrification from. Presumably this would also be a problem for an isolated "charging station" installation.

 

[duffield]

IIRC one of the issues with Uckfield is the lack of a suitable high-voltage grid line in the area to feed any electrification from. Presumably this would also be a problem for an isolated "charging station" installation.

Anybody able to work out if you could get a useful top-up-charge in (say) 15mins from a standard 415v 3-phase supply? (Probably a stupid question, just curious).

 

[MarkyT]

Anybody able to work out if you could get a useful top-up-charge in (say) 15mins from a standard 415v 3-phase supply? (Probably a stupid question, just curious).

I think that's the basis of Vivarail's fast charge system. It contains batteries itself which can charge slowly from a typical industrial or maybe even domestic single phase supply and then discharge quickly into a vehicle's traction battery periodically.

 

[big all]

i would say the the 25mile would need a 60 mile battery capacity to work
you would have hurst green to oxted and back to charge so about 6 mins plus change end time so about 12 mins better if more time available this assumes an oxted shuttle
now you would have charging at uckfield end but better to have enough for a round trip plus a 10% buffer in case off a problems