The Anonymous Widower

Moving The West London Line AC/DC Switchover To Shepherd’s Bush

London has a rail capacity problem, for both freight and passenger trains.

This report from Network Rail is entitled The London Rail Freight Strategy (LRFS).

One of the recommendations of the report is to move the switchover between AC and DC power on the West London Line to Shepherd’s Bush station. It says this about the switchover.

Extension of the overhead wires further along the WLL, to provide AC electrification as far south as Shepherd’s Bush station.

Two passenger train services run along the West London Line.

• Four tph – London Overground – Clapham Junction and Stratford
• One tph – Southern – Clapham Junction and Milton Keynes

Note.

1. tph is trains per hour.
2. London Overground would like to increase their service to six tph.
3. All trains stop at Shepherd’s Bush station.

The West London Line (WLL) runs between Willesden Junction station in the North and Clapham Junction station in the South.

These are the stations and their electrification status.

• Willesden Junction – 25 KVAC Overhead Electrification
• Shepherd’s Bush – 750 VDC Third-Rail Electrification
• Kensington Olympia – 750 VDC Third-Rail Electrification
• West Brompton – 750 VDC Third-Rail Electrification
• Imperial Wharf – 750 VDC Third-Rail Electrification

The switchover is performed North of Shepherd’s Bush station with the train moving.

These pictures show the electrification to the North of Shepherd’s Bush station.

This double-electrification allows switchover, whilst the trains are moving.

This is said in the Network Rail document about moving the West London Line AC/DC switchover to Shepherd’s Bush station.

Extending the Overhead Line Equipment south to Shepherd’s Bush would enable passenger trains to change traction source whilst making their scheduled station stop.

A slight extension to dwell times at Shepherd’s Bush may be required, but the elimination of the need to slow down or, especially, to stop, as is the case for GTR trains, at North Pole Junction would release a significant amount of capacity.

Recent work carried out on behalf of Transport for London calculated that the relocation of the changeover to the Shepherd’s Bush could provide an indicative net saving of 7 minutes per hour, which is equivalent to an additional path and some additional time for timetable flexibility.

The LRFS capacity analysis concluded that this intervention could potentially release up to two additional timetable paths an hour in each direction.

Moreover, the analysis advised that eliminating the need for GTR services to stop to change traction at North Pole Junction would be of significant performance benefit even today.

This sounds to me like this us a good solution, that will give winners all round.

• I went North yesterday on a GTR (Southern) service and can confirm, the stop to switch voltage at North Pole junction.
• Extra paths are always good news.
• I have a feeling that the overhead electrification on the route isn’t the best, so Network Rail may even have to replace it anyway.

What I like about the proposal, is that if the switchover point is moved to Shepherd’s Bush station and in the very rare occurence of a switchover failure, the passengers can be easily evacuated from the train as it will most likely be in Shepherd’s Bush station, rather than in the industrial wastelands of West London.

These pictures show Shepherd’s Bush station.

Note.

1. It looks like the bridges have been built high enough for overhead electrification.
2. The platforms appear to be able to handle long trains.
3. Putting up overhead gantries doesn’t look to be the most challenging of tasks.

I don’t think, that the engineering needed will be difficult and because of the gains outlined in the report, this project should be performed as soon as possible.

Should The AC/DC Switchover Be At Kensington Olympia Station?

The Network Rail document also muses about performing the AC/DC switchover at Kensington Olympia station.

This is said.

Although moving the changeover to Shepherd’s Bush would eliminate the need for passenger trains to slow down or stop at North Pole Junction, electrically hauled freight trains will still need to switch power supply modes whilst moving, wherever the AC/DC interface is located.

Due to the substantial incline facing trains running northward on the WLL, which increases in severity towards the Willesden end of the route, it would be preferable for the changeover to be made as far south as possible. This would enable freight trains to slow down to switch traction before reaching the worst of the gradient, giving them a much better chance of regaining line speed once drawing power from the OLE.

Although Kensington Olympia is less than a mile to the south of Shepherd’s Bush, the intervening route section is almost entirely level, with the incline commencing just before Shepherd’s Bush station and continuing to rise sharply along the rest of the WLL. The capacity and performance benefits of relocating the changeover are therefore likely to be greater if the overhead wires are extended to Kensington Olympia, removing the risk to traffic flow that would remain if freight trains were forced to switch whilst running uphill.

This would prepare the West London Line for the transition to electric freight that will be necessary as part of the decarbonisation of the railway over the next thirty years.

Resolving the current traction changeover issues for freight as well as passenger trains would support this transition by encouraging freight operators to invest in electric locomotives to run on the orbital routes, in the confidence that this constraint has been addressed.

Network Rail seem to have made a very strong case for switching between AC and DC power at Kensington Olympia station.

These Google Map shows Kensington Olympia station.

And these pictures show the station on a very wet day.

It doesn’t appear that there would be too many problems in electrifying Kensington Olympia station.

The only problem, may be the bridge at Addison Gardens to the North of Kensington Olympia station.

Although, Network Rail have an extensive range of tricks to get the wires through.

Conclusion

I believe, as probably do Network Rail, that Kensington Olympia station should be the station, where the switchover occurs.

But it’s all down to money.

It does seem to me, that the London Rail Freight Strategy is the first serious attempt to work out, the possible freight and passenger uses of the West London Line, which is one of those rail lines that has been designed by Topsy and accidents of history.

How many other rail routes in the UK, would be improved by a similar analysis?

Related Posts

These are related posts about the London Rail Freight Strategy (LRFS).

Decarbonisation Of London’s Freight Routes

Doubling Harlesden Junction

East Coast Main Line South Bi-Directional Capability

Gauge Improvements Across London

Gospel Oak Speed Increases

Headway Reductions On The Gospel Oak To Barking, North London and West London Lines

Heavy Axle Weight Restrictions

Kensal Green Junction Improvement

Longhedge Junction Speed Increases

Moving The West London Line AC/DC Switchover To Kensington Olympia

Nunhead Junction Improvement

Stratford Regulating Point Extension

Will Camden Road Station Get A Third Platform?

Will Clapham Junction Station Get A Platform 0?

 

June 21, 2021 - Posted by AnonW | Transport/Travel | Electrification, Freight, Kensington (Olympia) Station, London Overground, London Rail Freight Strategy, Shepherd's Bush Station, West London Line