What if the DfT gave £1 billion a year for electrification?

[Domh245]

Whilst that sounds like a good plan, it has a major issue. All of the missing third rail islands in the South are all fairly short and so the amount of existing third rail to be removed will also be quite short. Replacing third rail with OLE, in my mind, requires you to commit to long core routes being converted, for fleet reasons as much as anything else. Targets for conversion should be the likes of Victoria - Brighton, or the SWML as far as Southampton.

If you only convert some 3 times the distance that you installed third rail over, you'll only really be able to convert a few suburban branch lines, which means dedicated DV sub fleets and more complicated diagramming

 

[Kneedown]

I'm looking forward to HST running on third rail

HST or HS2?

 

[D365]

Thinking out loud, the big problem with 3rd rail (in terms of capacity) is the need for frequent substations. This is fine where there's lots of settlements, but less good in more rural locations.

You say that, but it’s the more urban areas which are actually causing problems. Building more and more 20MW Ludgate Cellars-type substations would take up a significant amount of land. Just another of the problems that DC electrification brings with it.

 

[HSTEd]

The problem with routinely dead rails in stations is that it convinces the idiots that ALL such rails are routinely dead, even out in the country.

Do we have to tell the passengers that it is routinely dead?
How many people are that interested in the mechanics of third rail operation?

Thinking out loud, the big problem with 3rd rail (in terms of capacity) is the need for frequent substations. This is fine where there's lots of settlements, but less good in more rural locations.

The cost of substations, especially lower power ones, is falling drastically though - as we see in some modern tram scheemes.
IN rural locations the traffic density is sufficiently low that volt-drop is less of an issue than it is on main line locations.

You say that, but it’s the more urban areas which are actually causing problems. Building more and more 20MW Ludgate Cellars-type substations would take up a significant amount of land. Just another of the problems that DC electrification brings with it.

How many locations actually need 20MW substations that are not already electrified though?

The huge supply of surplus EMUs have power outputs in the 1000kW range for 4-cars (Class 319).

EDIT:

Also given the proliferation of traction packs that can run at multiple voltages..... a third electrification standard could be introduced to solve the safety issues and power limitations of third rail whilst retaining the benefits of LVDC operation.

1500V bottom contact third rail for example.

 

[furnessvale]

Do we have to tell the passengers that it is routinely dead?
How many people are that interested in the mechanics of third rail operation?

You don't TELL passengers it is dead but youths larking about on stations will quickly suss this out and then transfer that thought to other areas.

 

[D365]

How many locations actually need 20MW substations that are not already electrified though?

The huge supply of surplus EMUs have power outputs in the 1000kW range for 4-cars (Class 319).

A 4-car Electrostar will burn at least 1500kW including aux. Whatever replaces the Kent Networkers will be similar, if not more.

Also given the proliferation of traction packs that can run at multiple voltages..... a third electrification standard could be introduced to solve the safety issues and power limitations of third rail whilst retaining the benefits of LVDC operation.

What benefits are those? All that 750V DC does is remove the need for transformers, and the overhead clearances.

I'm hardly the greatest fan of discontinuous electrification, but there may have to be a case for it in the future.

 

[HSTEd]

A 4-car Electrostar will burn at least 1500kW including aux. Whatever replaces the Kent Networkers will be similar, if not more.

Considering this tranche of electrification was proposed to use up cascaded stock, not to introduce all singing all dancing new units, this is not that much of an issue.
Especially since routes that would get 4-car 319s would likely only get 3-car stock if it was ordered new.

What benefits are those? All that 750V DC does is remove the need for transformers, and the overhead clearances.

<=1500Vdc installations are regarded by the IEC and other suitable regulatory bodies as Low-Voltage installations which drastically simplifies the safety and earthing requirements for substations and the like. (You have no need to have HV certified staff on the railway side, or provide complex safety earthing arrangements, especially if it is a small substation that is fed from a 400V supply)

With the advances in power electronics we are starting to get close to having widespread use of solid state power transformers that take in power at any utility distribution voltage (400V-11kV+) and output a fully controllable DC output (controllable in both voltage and current) and which will fit onto a utility distribution pole with a power of several hundred kilowatts.

Cooperative use of intertripping and power-converter switches will enable an approach where commodity unit-substations drawing from any available utility supply can be added to the railway adhoc, utilising hall effect current sensors to detect a high current condition in the adjacent rail and a combination of their power electronic switches and their AC side circuit breakers to break faults without resorting to very expensive and bulky DC circuit breakers

It is an entirely new paradigm where you might have a 400V-fed substation of a few hundred kVA every few hundred metres.

I'm hardly the greatest fan of discontinuous electrification, but there may have to be a case for it in the future.

Discontinuous electrification has few advantages over simple battery electric operation though.
In most cases where discontinuous is practical, full blown batteries will probably come out on top.

 

[D365]

In most cases where discontinuous is practical, full blown batteries will probably come out on top.

We're currently not getting more than 400-500kWh per four car battery unit. No chance of running a train at full power.

 

[GRALISTAIR]

We're currently not getting more than 400-500kWh per four car battery unit. No chance of running a train at full power.

Especially not a freight train.

 

[D365]

Especially not a fright train.

Exactly - that was one of my misgivings with the proposal initially.

 

[HSTEd]

We're currently not getting more than 400-500kWh per four car battery unit. No chance of running a train at full power.

The BEMU trial unit that was used on the deeside line apparently managed 470kWh in a short two car unit using lead acids.
But then again crash standards are rather more onerous than they were then

 

[D365]

The BEMU trial unit that was used on the deeside line apparently managed 470kWh in a short two car unit using lead acids.

I've got no idea about the finer details of that, but lead-acid cells were not considered for the IPEMU trial.