What are the causes of electrification projects taking ever longer, and how could this be rectified

[zwk500]

At the risk of getting shot down in flames...

If routes like the current TPE Leeds - Manchester route (mainly 75mph max, with scope to increase to maybe 90mph but not much further), how much cheaper and quicker would a side or bottom contact protected 3rd rail at say 1200v DC be to install. Multi voltage stock is now commonplace, the DC buses and motors tend to work at these sort of voltages anyway, no bridges to raise, no catenary to thread through tunnels, station canopies to alter, a whole lot of work is no longer required. Gapping can be addressed with a small supercaptitor power pack. 3rd rail can do 90-100mph, none of the existing route is good for mare than that. Installation could very simple taking advantage of short nightime periods. Containerised feeder stations. Might not be the gold atandard, but I am sure you could progress a lot quicker, at far less cost. After all the L&Y did side contact 1200v DC over 100 years ago.

Judging by current progress trains between Leeds and Manchester will still be diesel in 2040. We need to find a way to deliver cost effective improvements. And remember once you have done Standedge route you really need to do Calder Valley

If you ever get a new 'high speed route' between Leeds and Manchester that will be 25kV OHL but I think given the challenges and costs currently its pie in the sky. and if it ever does get built the 3rd rail would probably be due for renewal by then, so maybe revisit if its worth going to 25kV OHL, but by that point it would be local services only and the need may not be there to upgrade, just replace like for like, as the current barriers will still be there.

By the time you've lugged half a dozen substations on to the top of the Pennines, then added in resistive losses and the much greater likelihood of delay, and you've probably not saved yourself an awful lot. 25KV OLE with batteries would get rid of diesel on the TPE routes by 2030, making it much less important to wire the entire route in one go. Then there's also the issue of current draw, if we ever want electric freight on this line.
If you were wanting a cheaper option something like 3KV DC OLE might be worth exploring - it's a mature technology used in Germany and France, it's a high enough voltage that the resistance is low but shouldn't need as much clearance work. But a key advantage of the system we have at the moment is commonality. Trains can be simpler, supply chains are smoother, emergency parts can be got from neighbouring depots, skills and knowledge are transferrable around the country etc, etc. Having a bespoke system breaks that down and introduces hidden costs.

 

[stuu]

By the time you've lugged half a dozen substations on to the top of the Pennines, then added in resistive losses and the much greater likelihood of delay, and you've probably not saved yourself an awful lot. 25KV OLE with batteries would get rid of diesel on the TPE routes by 2030, making it much less important to wire the entire route in one go. Then there's also the issue of current draw, if we ever want electric freight on this line.
If you were wanting a cheaper option something like 3KV DC OLE might be worth exploring - it's a mature technology used in Germany and France, it's a high enough voltage that the resistance is low but shouldn't need as much clearance work. But a key advantage of the system we have at the moment is commonality. Trains can be simpler, supply chains are smoother, emergency parts can be got from neighbouring depots, skills and knowledge are transferrable around the country etc, etc. Having a bespoke system breaks that down and introduces hidden costs.

25kV can jump about 50mm at most in dry air. The clearance is mostly needed for mechanical movement of the contact wire, which doesn't change with the voltage. 3kV DC needs heavier wires and more frequent substations, so you would be spending more and adding in a new system for no reason.

Neither Germany nor France use 3kV DC, but Italy, Spain and Belgium do. They have all switched to 25kV for new railways

 

[zwk500]

25kV can jump about 50mm at most in dry air. The clearance is mostly needed for mechanical movement of the contact wire, which doesn't change with the voltage. 3kV DC needs heavier wires and more frequent substations, so you would be spending more and adding in a new system for no reason.

Fair enough.

Neither Germany nor France use 3kV DC, but Italy, Spain and Belgium do. They have all switched to 25kV for new railways

Ah, my mistake. I knew Germany and (southern) France had different spec voltages but confused which they were!

 

[yorksrob]

If you haven't got a natural diversionary route, it still doesn't solve it. Didcot to Oxford being a prime example.

Then it provides additional capacity to the inevitable stream of RRB's.

 

[Bald Rick]

If routes like the current TPE Leeds - Manchester route (mainly 75mph max, with scope to increase to maybe 90mph but not much further), how much cheaper and quicker would a side or bottom contact protected 3rd rail at say 1200v DC be to install.

no cheaper and certainly not quicker.

Firstly you’d have to go through the process of designing and gaining technical and safety system acceptance for a new electrification system. Even if it had been used before. That’s a couple of years’ work minimum.

Then you’d have to resignal the whole lot first before putting any DC down. Probably need to spend a lot of money on the track and at stations to deal with the return currents.

Then you’ll have to buy a new fleet of bespoke trains, with two types of electric and diesel capability, which could not be used to their full potential on the DC. Oh the freight guys would be very unhappy.

 

[The Planner]

Then it provides additional capacity to the inevitable stream of RRB's.

It makes the situation worse as being the quickest journey in any planner everyone will go for it leading to overcrowding.

 

[yorksrob]

It makes the situation worse as being the quickest journey in any planner everyone will go for it leading to overcrowding.

Some people might prefer the opportunity of getting the train. Better to run a service.

 

[The Planner]

Some people might prefer the opportunity of getting the train. Better to run a service.

If they want to run the risk of taking a very limited journey opportunity on a crush loaded train which would likely be delayed due to that very reason then thats up to them. I know I wouldn't.

 

[MarkyT]

Neither Germany nor France use 3kV DC, but Italy, Spain and Belgium do. They have all switched to 25kV for new railways

Ah, my mistake. I knew Germany and (southern) France had different spec voltages but confused which they were!

'Germanic central Europe', i.e. Germany, Switzerland and Austria, as well Sweden and Norway, use 15kV AC at the weird frequency of 16.7Hz (historic reasons, legacy of being early adopters). AFAIK none of these countries has implemented any 50Hz electrification (apart from an experimental German branch line in the 1950s), nor have they any plans to do so. New major route construction in most (all?) other European countries has used 25kV, regardless of legacy supply systems.

 

[ABB125]

'Germanic central Europe', i.e. Germany, Switzerland and Austria, as well Sweden and Norway, use 15kV AC at the weird frequency of 16.7Hz (historic reasons, legacy of being early adopters). AFAIK none of these countries has implemented any 50Hz electrification (apart from an experimental German branch line in the 1950s), nor have they any plans to do so. New major route construction in most (all?) other European countries has used 25kV, regardless of legacy supply systems.

I think the Germanic countries use 16.7 Hz as you say, but the Scandinavian countries still use 16 2/3 Hz because they haven't switched to 16.7 like Germany etc. The reasons for 16.7 Vs 16 2/3 I don't really understand!

 

[mike57]

I think the Germanic countries use 16.7 Hz as you say, but the Scandinavian countries still use 16 2/3 Hz because they haven't switched to 16.7 like Germany etc. The reasons for 16.7 Vs 16 2/3 I don't really understand!

The switch to 16.7 Hz was triggered by the use of a particular type of rotary converter, which if run at exactly 1/3 of grid frequency introduced some unwanted effects related to a DC component appearing within the windings, moving to 16.7Hz solved the problem. Its no longer a problem with static converters. I think Norway and Sweden still use 16 2/3Hz, if you generate directly its not a problem so there was never the requirement to change. I suspect the difference is not noticable as its only about 0.2%

 

[ABB125]

The switch to 16.7 Hz was triggered by the use of a particular type of rotary converter, which if run at exactly 1/3 of grid frequency introduced some unwanted effects related to a DC component appearing within the windings, moving to 16.7Hz solved the problem. Its no longer a problem with static converters. I think Norway and Sweden still use 16 2/3Hz, if you generate directly its not a problem so there was never the requirement to change. I suspect the difference is not noticable as its only about 0.2%

Thanks very much.
I wonder why Denmark chose 25kV electrification, when both its neighbours use 15kV? Seems to be a bit of an unnecessary operational complication. Though I suppose problems might arise if you had 15kV 16.7 Hz and 16 2/3 Hz next to each other?

 

[zwk500]

Thanks very much.
I wonder why Denmark chose 25kV electrification, when both its neighbours use 15kV? Seems to be a bit of an unnecessary operational complication. Though I suppose problems might arise if you had 15kV 16.7 Hz and 16 2/3 Hz next to each other?

Possibly because they only started to electrify in the early 80s, and by then 25KV was the accepted international standard?

 

[mike57]

Thanks very much.
I wonder why Denmark chose 25kV electrification, when both its neighbours use 15kV? Seems to be a bit of an unnecessary operational complication. Though I suppose problems might arise if you had 15kV 16.7 Hz and 16 2/3 Hz next to each other?

Denmark began electrification much later, Low frequency electrification (i.e. significantly below 50Hz) has been around since the early 1900s, with the LBSCR adopting 6600v 25Hz back in around 1908/9. The reason for the much lower frequency is that you can use a series wound motor on low frequency AC with a few modifications. At 50Hz multi horsepower series motors wound are just not feasible, its to do with reactance and losses. Smaller motors, such as are used in washing machines and power tools are fine at 50Hz if the magnetic core is laminated. The idea of the low frequency system with a transformer is that you dont need starting resistances, which result in losses, and take space, need cooling etc. Instead you use various lower voltage taps to ensure starting current is with the system/motor capacity. All the more significant on a service such as the LBSCR railways out of Victoria, with close together stops.

The Germanic and Nordic system also used series wound motors, again with installations dating from the early 20th century. Bear in mind all this development took place before the advent of any form of power conversion electronics beyond rotary converters.

50Hz electrification only became a possibility once onboard rectification became possible. In fact the early AC locos use mercury arc rectifiers, which always had there problems, it wasnt until the advent of semiconductor rectifiers the AC 50Hz electification really took off, using Germanium rectifiers in the first instance, then swapping to Silicon.

There are some interesting resources in the Smithsonian Library which are avaiable on line, the Electric Railway Journal, from the period 1909 to 1914 which describe the LBSCR south london system. If anyone is interested I will try and dig out the link, there are some wonderful pictures of workers stringing the catenary using huge wooden step ladders with trains on other lines carrying on as normal.

Links to LBSCR resources:

Electric railway journal : Free Download, Borrow, and Streaming : Internet Archive

Formed by the union of Street railway journal and Electric railway review

archive.org

Electric railway journal : Free Download, Borrow, and Streaming : Internet Archive

Formed by the union of Street railway journal and Electric railway review

archive.org

Electric railway journal : Free Download, Borrow, and Streaming : Internet Archive

Formed by the union of Street railway journal and Electric railway review

archive.org

Here is a picture taken at Balham c1910.

 

[MarkyT]

Thanks very much.
I wonder why Denmark chose 25kV electrification, when both its neighbours use 15kV? Seems to be a bit of an unnecessary operational complication. Though I suppose problems might arise if you had 15kV 16.7 Hz and 16 2/3 Hz next to each other?

Possibly because they only started to electrify in the early 80s, and by then 25KV was the accepted international standard?

The S-tog network around Copenhagen was electrified quite early, starting in the 1930s using 1650V DC overhead, which it retains today. As zwk notes, DSB started mainline electrification in the 80s and the extent is even now still quite limited. Note the Øresund Bridge link to Sweden didn't exist at that time, although I think it had been an aspiration for nearly a century before construction actually started. There's only one wired interface to the German 15kV system currently, at Padborg. There will be another when the Fehrmarn belt tunnel is completed.