Network Rail considers the West Coast Main Line (WCML) to be the busiest mixed traffic railway in Europe. It carries 125mph passenger trains from London to the West Midlands, North West, and Scotland and is used by 90% of intermodal UK rail freight which has a maximum speed of 75mph. Traffic on the line has been steadily increasing. In 1994 there were seven daily passenger trains from Glasgow to London. Now there are 26.
In 2006 Network Rail commissioned an in-depth study to find the best way of providing additional capacity as, with increasing traffic, the WCML between London and the North West was forecast to be full by 2020. The study found that the provision of a new high-speed line was the best solution and was the basis for the development of the HS2 project. The 2006 study correctly forecast that the WCML will by now be at full capacity south of Crewe, yet following the curtailment of HS2 two years ago there are no proposals to address the capacity issue between Rugby and Crewe that was identified 20 years ago.
North of Preston
Although passenger traffic on the northern part of the WCML is much less than its southern end, this is a two-track railway on which passenger traffic is mixed with freight traffic. As all railway operators know, mixing fast passenger trains with slow freight trains destroys capacity. Furthermore, trains between Preston and Scotland must twice climb to 1,000 feet above sea level on the steeply graded lines to Shap and Beattock summits. Although the WCML is electrified, most freight services are diesel hauled by 2,400kW Class 66 locomotives which can only manage slow speeds up these climbs.
The sectional running time for the 16km climb up to Beattock summit for a freight train is 27 minutes compared with seven minutes for a passenger train which goes over the summit at its 90mph linespeed. Hence, over this section the freight train consumes three passenger train paths. The typical speed of an intermodal freight hauled by a Class 66 over Shap Summit is 25mph with the resultant loss of at least one train path. This compares with 48mph for a single 4,000kW Class 88 electric locomotive. Some Freightliner trains use 2 x Class 90 electric locomotives and go over the summit at the freight train’s maximum speed of 75mph.
With extensive use of diesel traction, there are few daytime intermodal freight trains north of Preston where the WCML timetable flights passenger and freight trains into windows, each of about 30 minutes. Thus, to the lineside observer there are no trains for much of the time as slower freight trains are given a head start. If, as can happen, a passenger train catches up with a freight train, the freight may have to be looped to let the passenger train to pass. The freight train then spends a lot of time of braking and accelerating which further reduces capacity and can slow down following passenger trains.
Yet those within the rail freight industry consider that there is potential to operate many more daytime intermodal freight trains between the flights of passenger trains if freight trains were electrically hauled. As well as going much faster over the summits of the northern fells, electric freight offers greater acceleration and therefore faster average speeds. This view is reinforced by RSSB report T1301 on the optimisation of sectional freight running times. This concluded that existing timings do not recognise the benefits of higher-powered electric traction.
Diesels under the wires
There are various reasons why so many trains are diesel hauled under the WCML wires. One is that, at some locations, the WCML power supply is at its limit and so can’t support more electrically hauled freight trains. In addition, the higher cost of electricity disincentivises the use of electric locomotives although their use reduces journey times which, depending on the nature of the service, can offer savings from improved asset utilisation and reduced train crew cost.
Another reason is that currently freight operators have no routes that can be hauled end-to end by electric locomotives. Hence a locomotive change is needed if WCML freight is to be electrically hauled. This is costly as it requires two locomotives, two drivers, and someone to couple and uncouple them, and adds time to the journey. This would not be required if short key freight lines could be electrified, for example the unelectrified 6km single line to the port of London Gateway which carries over 40 trains per day. This number is set to increase with plans for a second rail terminal at the port.
One objection to such infill electrification is that this is unnecessary now that there are freight bi-mode locomotives such as the Class 99. Yet the Class 99 locomotives cost around £5 million each. More importantly, from a rail freight business perspective, the lease cost of the Class 99 is much greater than that of 35-year-old Class 90 locomotives whose capital cost has been written off.
These costs compare with that of £10 – 15 million to electrify the 6km single line to London Gateway. Thus, there would seem to be a compelling case for electrifying this line. This would help deliver the Government’s rail freight growth target, make the best use of existing underutilised electric locomotives and as described in this article, benefit WCML passengers.
Faster freight
Due to the slow speed and acceleration of diesel-hauled freight trains, between Preston and Carlisle there are few daytime freight paths. Between Preston and Carlisle passenger trains typically average 80mph with a single stop at Oxenholme or Penrith and 105mph between Carlisle and Carstairs. On this basis, if it were possible to run freight trains at 90mph, it may be possible to significantly increase in daytime freight paths.
More importantly, 90mph freight trains could potentially create additional train paths on the congested section of the WCML north of Rugby. Currently, no solution has been proposed to alleviate this congested line for which traffic demand is predicted to increase. As it will be at least a decade before a new line or other infrastructure enhancements can provide the required additional capacity, 90 mph freight is an option that is worth exploring. This would require electric traction and so would need:
- Sufficient electric locomotives, this may require some rail freight operators to acquire electric locomotives.
- Enhanced power supplies.
- Wagons with 140km/h bogies, this would require a significant investment as only a limited number of container flats use megafret bogies designed for 140km/h running.
- Freight trains to slow down to 75mph when running next to passenger platforms.
- Freight infill electrification.
Though this would involve significant costs, this is likely to be far less than the cost of infrastructure investment to deliver extra capacity and would be deliverable in a much shorter timescale than such enhancements. It should be noted that digital signalling cannot resolve the capacity constraint of mixing slow and fast trains.
It also needs to be recognised that faster freight potentially offers significant benefits to both passenger and freight businesses.
Electric freight
Between 06:00 and 18:00 there are around 4,000 HGVs carrying containers on the M6 north of Preston alongside the WCML, on which only a handful of intermodal trains can operate during this time. Much of this long-distance road freight should be on the railway. Rail freight produces 76% less CO2 per tonne than road haulage while road freight has significant societal costs, which include congestion, pollution, noise, and accidents.
Yet the WCML currently does not have the capacity to carry additional intermodal traffic. As this feature shows, electrically-hauled freight trains could both provide additional capacity and run at speeds that don’t disrupt passenger trains. Electric locomotives are also more reliable than diesel locomotives and so are less likely to fail and cause significant delay to passenger trains.
Although electric freight train haulage offers additional train paths, rail freight companies have little incentive to stop using diesel locomotives. Hence the track access charge should be reduced for higher performing electric freight trains that offer additional capacity. The provision of freight infill electrification, and particularly the short line from London Gateway, would also eliminate a barrier to the use of electric traction.
In the longer term, the introduction of 90mph freight trains potentially offers significant benefits along the entire WCML, especially the congested section north of Rugby for which there is currently no plan to increase capacity. Hence progressing this concept would be a worthwhile initiative.
The chart is a WCML timetable graph showing trains north of Preston between 1200 and 1400 on which actual diesel and electric freight train times from Realtime trains have been overlaid. This shows the significant conflict between diesel daytime freight and passenger services which is not such a problem for electric freight. The graph also shows how a 90mph freight service would almost keep pace with WCML stopping passenger trains.
The rail freight business is one of the few commercial successes of rail privatisation. However, it has tight profit margins and must compete with road freight which has energy and track access / road levies costs that are respectively 82% and 47% lower than rail freight. Hence it is neither realistic nor reasonable to expect rail freight businesses to carry all the costs of substantially increasing electric freight haulage as this also benefits rail passengers. Furthermore, if the rail freight business is to invest in new locomotives, clarity about future electrification is required.
The Government intends to publish an infrastructure and rolling stock strategy by mid-2026 as part of the introduction of Great British Railways. If this strategy is to follow the promised whole system approach, it must address the need for electric rail freight and recognise its significant benefits for both the rail freight and rail passengers.
Image credit: Network Rail
In the early 1970s, I was lucky enough to work with a PACE 231R. Not an unknown light freight engine, but probably one of the most powerful analogue computers ever built, that could solve a hundred simultaneous differential equations at once using thermionic valve circuitry. Their most famous application was at NASA, where two of them formed the analogue half of the moon-landing simulator.
There were a handful of these powerful beasts in the UK at ICI Plastics, where I worked, BMC, Cambridge University and British Rail Research at Derby.
At the time, British Rail were trying to run freight trains faster and the four-wheel freight wagons of the time were derailing with an unwanted regularity. So the problem was given to British Rail Research and the problem was put on the PACE 231R. The problem was solved and the lessons learned were applied to the Mark 3 Coach and the InterCity 125.
After privatisation, the research went to the National Railway Museum and out of curiosity a few years ago, I tried to look at it, but was told it was commercially sensitive to Bombardier. It is my belief, that if this research were to be continued at one of our best universities, that faster freight bogies could be developed, that would help to create the extra freight paths needed on the WCML.
Note that I have some copyright free pictures of ICI’s PACE 231R.