The proposed High Speed Rail (HSR) project can not be part of a green solution to Britain’s transport infrastructure problems.

The carbon emissions from a trip using HSR would be only 25% less than doing the equivalent trip by air and more than doing the equivalent trip by car* hardly the sort of transport emission reductions that we should be aiming for. HSR also requires a larger capital investment than air travel with significantly higher embedded emissions for HSR than for air travel.

HSR also requires a wider rail corridor than similar but slower rail services thus requiring a larger swathe of land set aside than for slower trains. This is mostly because of the higher noise levels produced by high speed rail than their slower counterparts. Noise pollution from rail services is strongly correlated with speed.

The high carbon emissions are predominantly due to the energy required in overcome air resistance when the trains are travelling at hight speed. Providing this extra energy on the national grid will be problematic when there are going to be other demands on the national grid, for example extending the electrification of the current rail system, moving petrol and diesel powered cars, trucks and buses to electric powered vehicles will increase demand on the national grid. This is also going to happen at the same time as the national grid will gradually move to sourcing its electricity to sustainable sources and hopefully closing down coal, gas and nuclear powered power stations.

The more energy we demand for our transport system to be supplied by the national grid the more difficult it will be to close down carbon emitting power stations because the increased sustainable energy supply may not be able to meet the increase demand for energy.

HSR is far more expensive than a slower train service. The cost of the compulsory purchase of the larger swathe of land required for HSR is higher, the cost of the rolling stock is higher due to the required higher specifications, the running costs of the HSR service is significantly higher due to increased requirement for energy compared to a slower train service. Much more could be achieved with the same money if it was used differently.

Investment in our current rail system to improve reliability and capacity is necessary, for example the Cotswold rail line that I regularly use is single track for much of its length and though sections of the line are being upgraded to dual track the best solution would be to make the whole length of the line dual track. As it is delays in a train service in one direction have an immediate knock on effect on the trains travelling in the opposite direction, and the lack of dual track restricts the capacity of the line.

As well as investment in our train system some simple changes like getting rid of first class all together or limiting first class to a single carriage on a train would be sensible, all too often the standard fair section of a train is packed to overflowing with 2 or 3 people in each of the first class carriages.

There are real capacity problems with Britain’s train service that can only be fixed by adding new train lines and this is why HSR is being promoted. But I think that because of the reasons given above HSR is not the answer. I think adding new train lines to be operated at slower speeds instead of aiming for a 250 mph HSR system is sensible. For example if the new lines operated with a speed of 125 mph with sections where 150 mph is possible providing flexibility so that trains can catch up if they get behind schedule would be an improvement. But most importantly the new system should be designed to increase capacity and reliability and we would still achieve significantly shorter travel times between major UK destinations. A train system running at half the speed of HSR would use less than half the energy of HSR. The reduced cost would also mean that there should be extra money for further investment in our current rail system.

I agree with much that George Monbiot wrote in his article on HSR but I suppose I disagree with him on the need for extra capacity. Even with the incredibly expensive train fares the train to Oxford from London late in the evening is so full that passengers have been forced to miss the train. I also think that restricting the number of landing slots available for regional flights is something that should be considered.

* Assuming that HSR is powered by electricity generated using the current UK mix for electricity generation.