Is There a Place for Diesel Trains in the UK?

 by Ben Millard

At the time of writing, 29% of the UK’s train network is powered by diesel. Diesel is a fossil fuel that, when combusted, produces energy and carbon dioxide as a product. Carbon dioxide is a greenhouse gas which causes climate change due to the creation of a “blanket”, effectively trapping radiation from the sun in the atmosphere. The effects of climate change are potentially devastating, hence why there is enormous pressure on governments to ensure that there are policies in place to prevent its consequences. However, a large proportion of trains in the UK still run on diesel. In this article, I will investigate why this is still the case.

The oldest electric trains in the UK were built in 1976 and are used by Southern along the East and West Coastway lines, from Brighton to Southampton. Nevertheless, almost 50 years later, the UK still relies on diesel to power its trains. This is mostly down to cost; Great Western spent $2.8 billion on their electrification scheme in 2015, and costs are expected to rise. Reform is needed but it is expensive so it may take a long time to change trains to electric power. This is why the government has set 2040 as a target for the end of the use of diesel trains. However, the target may be achieved earlier if rail companies are educated about the long term benefits to them of electric power. Electric trains are cheaper to run and have lower service costs, thus rail companies will save money after a long period of time. 

A large drawback of electrification is that either an additional electric track next to the tracks for the wheels or an overhead electric wire is required. This obviously requires new electric trains to be bought, thus increasing costs further. In the South-West of England, where diesel trains run on single rails with very few trains per day, this spending cannot be justified as the revenue earned by these tracks is insufficient to pay for their electrification. A government subsidy could help in these situations as it would reduce the cost of the electrification and also reduce the long term costs of climate change to the government. Unfortunately, these costs are underestimated by the government so they are reluctant to hand out subsidies. 

As an intermediary step, the government could encourage more people to use the trains in the parts of the country where diesel trains are used. This would reduce the use of cars, which also produce fossil fuels. In this way, the costs of climate change would still be reduced as the amount of diesel used by trains will remain fairly constant as the mass of the passengers is insignificant compared to the mass of the train and less fossil fuels will be combusted by cars. Furthermore, if more people used the trains, firms would generate more revenue. This could incentivise them to spend profits on electrification and reduce the need for government subsidy. 

Overall, diesel trains have no real place in the UK. In a world where some countries have completely electric rail networks, our reliance on fossil fuels seems antiquated. The 2040 target is a step in the right direction but further help from the government is required to realise that target.