Technical

Our vision to open local railway stations to serve local communities would be neither feasible nor economically viable if we were expecting the fast trains between London and Penzance to stop at all these proposed new stations.

The intention is that these new small local stations will provide community access to a carefully integrated rail network system. Members of the public will be able to travel by rail to other local stations and also to the main line stations to take advantage of the conventional long distance fast services. When the local stations are fully established it may be that the existing long distance trains will stop at fewer stations and so will offer an even faster service.

Our plans will only be finalised after the conclusion of a comprehensive feasibility study, but the principle is eventually to have environmentally-friendly sprinter type trains connecting passengers from their local stations to the fast diesel powered rail services.

Initially this concept involving additional Sprinter-type trains will not be possible, but some critical stations could soon be re-opened providing this was part of the overall plans for an integrated rail network as envisaged by the feasibility study.

For example if the first new station to be opened was Langport, this would connect residents of Langport with Taunton and Castle Cary and the existing diesel powered trains would stop at Langport. This would be an interim arrangement before the Somerset District and Circle line became established with its smaller sprinter-type trains connecting Langport and intervening stations to Castle Cary or Westbury to the east or Taunton and intervening stations to the west.

Members of the transport committee from Transition Langport believe that Somerset can harness the joint potential of locally produced biomethane and the ex-London Underground trains.

Many of the Underground trains on the District and Circle Lines in London are being taken out of service. They are being sold off to be refurbished for use elsewhere and are being replaced by more modern trains, such as those now operating on the Hammersmith & City Line.

Hence the name ‘Somerset District and Circle Line’ which will eventually serve a series of re-opened and existing stations on a circular route in the district of Somerset.

Starting the circular route in Langport, for example, the proposed route for the new stopping trains would pass through Langport, Taunton, Bridgwater, Highbridge, Weston-super-Mare, Weston Milton, Worle, Yatton, Nailsea, Parson Street, Bedminster, Bristol, Keynsham, Oldfield Park, Bath, Freshford, Avoncliffe, Bradford on Avon, Trowbridge, Westbury, Frome, Bruton, Castle Cary, Somerton and back to Langport.

Rather than electrifying the rails, which powered the Underground trains in London, the intention is that the electricity will be generated on board the refurbished District and Circle line trains using biomethane, which would power the electric motors to drive the train.

Biomethane is renewable natural gas made from waste organic materials by the natural process of anaerobic digestion.

The fossil fuel natural gas that comes from the North Sea took thousands of years to form, millions of years ago. We can now make the same gas, biomethane, in about 18 days from food wastes using anaerobic digesters. Biomethane to power these trains can also be provided by harnessing and cleaning up the biogas which is produced at landfill sites.

The passenger carriages of these sprinter trains will be drawn by another unit which will contain the biomethane and a generator. The biomethane fuels an engine that runs the generator and the electricity produced provides the power for the train.

These sprinter trains and re-opened stations will allow passengers who presently have to drive to the main railway stations at Taunton or Castle Cary, to travel in a much more sustainable and environmentally friendly manner.

ENERGY

Not only is biomethane the most environmentally friendly fuel in the world, but transport based on steel wheels rolling along steel rails requires much less energy than transport which is based on rubber tyres rolling on a tarmac road.  The latter wastes energy which is being used to flex the tyres.

Hence when travelling on a level or gently sloping railway track at a constant speed a train requires considerably less energy to transport its passengers than does a bus or a coach travelling on a road which has hills and bends.

In order to slow down an electric train before it stops at a station, the current can be reversed and the electric motor powering the train then becomes a generator. This electricity generated during the slowing down of the train can charge a storage device so that the same electricity can then be used towards accelerating the train back up to speed as it leaves the station.

This system of ‘regenerative braking’ is used in some racing cars as it is very efficient and results in less weight of fuel having to be carried.

When the brakes are applied to a bus or a coach to slow it down for corners and junctions and traffic lights or to stop for passengers, the energy is wasted as heat and so more fuel is then required to accelerate the vehicle back up to cruising speed.

Allied to this very efficient braking and accelerating method for the lightweight sprinter-type trains on the Somerset District and Circle Line will be an electromagnetic system to prevent wheel slippage under braking and accelerating which will also save energy.