Great Western Main Line electrification - ongoing discussion

[whole diary]

[YouKnowNothing]

Has there been any movement on when they expect the lines to reach Cardiff? It’s all gone quiet after they announced the delay....

[Adrian]

Still a lot of masts to go up between Severn Tunnel and Magor.  Will the wiring taking place over Christmas just complete the English side?

[grahame]

Still a lot of masts to go up between Severn Tunnel and Magor.  Will the wiring taking place over Christmas just complete the English side?

The Christmas to New Year closure of the Severn Tunnel is to wire in the Severn Tunnel Junction area - thus the route via Gloucester will not be available.   GWR^▸ (Great Western Railway) do not have enough crew / route knowledge / capacity to route Swansea trains via Malvern, so it's buses ...

[froome]

With today's dreadful disruption in mind, it seems timely to ask a question I've been meaning to ask for some time.

Just how susceptible are overhead wires to being damaged?

Whenever i travel along lines fed by overhead wiring, the cables look to me to be very susceptible to many sources of potential danger, from high winds and other weather related factors to damage caused by vandals or interaction with the trains themselves. What sort of risk analysis has been done on their use and what have they shown?

Obviously these are large questions that will have complex answers, but given the inflexibility of any sort of rail system, the susceptibility of a major part of that system, in this case, the prime energy source, must have been given much thought before introduction. Are there better ways to provide electricity that reduce substantially this susceptibility?

[Timmer]

The sad thing is all that has gone on these past few years on the GW^▸ (Great Western) mainline and now last night has given electrification a bad name yet it has been a huge success on the WCML^▸ (West Coast Main Line) and on mainland Europe. Not as successful on the ECML^▸ (East Coast Main Line) but that was because it was done on the cheap.

I still firmly believe electrification is still the right answer for all rail and not relying on diesel.

[Electric train]

With today's dreadful disruption in mind, it seems timely to ask a question I've been meaning to ask for some time.

Just how susceptible are overhead wires to being damaged?

Whenever i travel along lines fed by overhead wiring, the cables look to me to be very susceptible to many sources of potential danger, from high winds and other weather related factors to damage caused by vandals or interaction with the trains themselves. What sort of risk analysis has been done on their use and what have they shown?

Obviously these are large questions that will have complex answers, but given the inflexibility of any sort of rail system, the susceptibility of a major part of that system, in this case, the prime energy source, must have been given much thought before introduction. Are there better ways to provide electricity that reduce substantially this susceptibility?

The area damaged is in the Hanwell area, this is in the most part still the older Mk3 "Headspan" system.  Headspan problem is when a wire is "ripped down" on one line it usually dislodges the other lines; the OLE^▸ (Overhead Line Equipment, more often "OHLE") used on the GWML^▸ (Great Western Main Line) west of Airport Jcn is independently mechanically registered with this system one wire being "ripped down" is very unlikely to effect adjacent lines, other than perhaps debris which can be quickly removed.


Its worth noting the OLE has quite a high (mechanical) tension on it, which has to be dealt with carefully when is dislodged

[froome]

With today's dreadful disruption in mind, it seems timely to ask a question I've been meaning to ask for some time.

Just how susceptible are overhead wires to being damaged?

Whenever i travel along lines fed by overhead wiring, the cables look to me to be very susceptible to many sources of potential danger, from high winds and other weather related factors to damage caused by vandals or interaction with the trains themselves. What sort of risk analysis has been done on their use and what have they shown?

Obviously these are large questions that will have complex answers, but given the inflexibility of any sort of rail system, the susceptibility of a major part of that system, in this case, the prime energy source, must have been given much thought before introduction. Are there better ways to provide electricity that reduce substantially this susceptibility?

The area damaged is in the Hanwell area, this is in the most part still the older Mk3 "Headspan" system.  Headspan problem is when a wire is "ripped down" on one line it usually dislodges the other lines; the OLE^▸ (Overhead Line Equipment, more often "OHLE") used on the GWML^▸ (Great Western Main Line) west of Airport Jcn is independently mechanically registered with this system one wire being "ripped down" is very unlikely to effect adjacent lines, other than perhaps debris which can be quickly removed.


Its worth noting the OLE has quite a high (mechanical) tension on it, which has to be dealt with carefully when is dislodged

Many thanks, that is very helpful. And I agree with all of Timmer's comments.

[Bmblbzzz]

What caused the wire this morning to be "ripped down", if that is what has happened? Something falling on it? Vandalism? Malfunctioning pantograph? ...

[TaplowGreen]

What caused the wire this morning to be "ripped down", if that is what has happened? Something falling on it? Vandalism? Malfunctioning pantograph? ...

Could it be Driver error? If so, I suspect someone is feeling rather uncomfortable this morning...…………….

[broadgage]

What caused the wire this morning to be "ripped down", if that is what has happened? Something falling on it? Vandalism? Malfunctioning pantograph? ...

Could it be Driver error? If so, I suspect someone is feeling rather uncomfortable this morning...…………….

I rather doubt it. All the driver can do is raise or lower the pantograph, perhaps in the wrong place.

Pantograph lowered when it should remain up--------------Train looses power and coasts. No contact with overhead, therefore no damage.
Pantograph raised when it should be lowered.-------------Pantograph liable to be knocked of  by a bridge or signal gantry. No overhead present to be damaged.

If the pantograph is improperly raised just before entering an electrified section, then no damage should be caused because the overhead is ramped at the entrance.

A defective pantograph seems the likely cause with defective overhead a distinct possibility. Either can result in the overhead getting caught UNDER the pantograph and pulling down the wires.

[a-driver]

Wouldn’t be driver error, could be a whole manner of things... train fault, infrastructure fault, obstruction on the overhead or vandalism. 

[ChrisB]

Has there been any movement on when they expect the lines to reach Cardiff? It’s all gone quiet after they announced the delay....

This Q came up at the Great Western Railway (GWR^▸ (Great Western Railway)) Stakeholders Conference yesterday & Andrew Haines, MD, said next summer, if I remember correctly.

What caused the wire this morning to be "ripped down", if that is what has happened? Something falling on it? Vandalism? Malfunctioning pantograph? ...

Answered already in the disruption in Thames Valley thread....
An on test ECS^▸ (Empty Coaching Stock) 802 recently delivered was being moved from North Pole depot to Stoke Gifford depot....reportedly by a GB^▸ (Great Britain) Railfreight  (GBrF) driver. What actually caused the failure will be under investigation still, I suspect.

Edit: VickiS - Clarifying Acronym

[SByers]

With today's dreadful disruption in mind, it seems timely to ask a question I've been meaning to ask for some time.

Just how susceptible are overhead wires to being damaged?

The Swiss mountain railways are mainly overhead high tension line. The actual supports seem to be flimsy wooden poles. Yet it all works through most weathers.

[Bmblbzzz]

A defective pantograph seems the likely cause with defective overhead a distinct possibility. Either can result in the overhead getting caught UNDER the pantograph and pulling down the wires.

I'm struggling to see, in my mind, how that happens. All I can think of is the pantograph lifting, hitting the overhead line and not stopping but continuing, pushing the line to one side and getting it trapped underneath. Seems kind of complicated though. 

[Electric train]

Has there been any movement on when they expect the lines to reach Cardiff? It’s all gone quiet after they announced the delay....

This Q came up at the Great Western Railway (GWR^▸ (Great Western Railway)) Stakeholders Conference yesterday & Andrew Haines, MD, said next summer, if I remember correctly.

What caused the wire this morning to be "ripped down", if that is what has happened? Something falling on it? Vandalism? Malfunctioning pantograph? ...

Answered already in the disruption in Thames Valley thread....
An on test ECS^▸ (Empty Coaching Stock) 802 recently delivered was being moved from North Pole depot to Stoke Gifford depot....reportedly by a GBrF driver. What actually caused the failure will be under investigation still, I suspect.

I would not write anything into it being a GB^▸ (Great Britain) Railfreight (GBrF) driver most TOCs^▸ (Train Operating Company) use a contracted in FOC^▸ (Freight Operating Company) to move new stock about, carry out test runs and mileage accumulation, they are no less able or skilled than a TOC Driver.

Edit: VickiS - Clarifying Acronyms