17 July, 2012 - 10:09 By News Desk

“A modern railway for the 21st century”. Really?

There has been a lot of enthusiasm from train enthusiasts over the announcement of £9Bn investment over the next several years 'providing a modern railway for the 21st century'. I think what they really mean is 'forcing a continuation of a 20th century railway into the mid 21st century. It is an opportunity missed. I think the money could be much better spent.

When I look at railways, I see a direct analogy with the telecomms network. In the old days, when you made a call, you had a wire for yourself, all the way from your phone to the other one. It was expensive, essentially because it need a lot of wires to provide the capacity.

When time division multiplexing came in, you started sharing the wire with other people. The signal from your voice was packetised, greatly compressed in time and sent with many others along the same wire. Later systems managed even more multiplexing. The result is that today, fixed line telecomms is almost free by comparison to prices back then and even mobile comms is very cheap.On today's regional railway, a train goes past maybe every 15 minutes, giving occupancy of around 0.4%. The primitive signalling system, combined with human drivers, means that the line is blocked for other trains for a considerable time either side of its passing, making for a system not unlike the old telecomms circuit switched network. It is no wonder tickets are expensive when the line is so underused.

We need packetisation and asynchronous time division multiplexing on rail too. An asynchronous packet switched network can run at 80% load before congestion even starts to show. Doing something similar same to the rail network as has been done in telecomms could greatly increase capacity, reduce journey times and decrease prices.The first change needed is to replace the long, heavy trains that hold 1000 people with light, short pods that hold maybe six. These would be the 'packets' compared to the circuit switched traditional trains. Because only a few passengers are needed for each to fill, an individual passenger would only wait a short time before a pod would be available to go to their destination, instead of waiting for a rigid timetable. Obviously, there would need to be a maximum wait, even if the passenger has to leave alone.Secondly, they would replace drivers by computers that can talk directly to those driving other pods and coordinate traffic efficiently. There is no need for an expensive signalling system, simple wireless direct connections could work ok. They would be cheap to make and very many of them could run centimetres apart, giving up to 200 times the capacity of today's rail. They could even form virtual trains that could mix with conventional ones on an old style network during a long upgrade period. But each pod would be going to a different destination and peel off at a station sideline to drop its passengers.Thirdly, just as wireless electricity is being demonstrated for home appliances, why not apply this on rail, with inductive pads now and again instead of the expensive and clumsy overhead, to top up super-capacitors or small batteries in each pod. Since pods can run happily in direct contact with each other, any pod breaking down could easily be pushed to the next station for repair.A very similar system could be developed for road users too. Self driving cars have been well proven already, and it would increase road capacity if we did this on roads too. Electric self-driving cars could be the basis of a replacement for public transport, which could provide end-to-end taxi-like service at very low cost, more socially inclusive since people wouldn't have to walk to bus stops, and it would extend far beyond existing bus routes.If roads have inductive pads to recharge the pods frequently, then we only need small batteries for the short trips on local roads at each end of a journey. And then, linking the road and rail systems, there is no reason why the same pods could not work on both rail and road. In fact, if we ripped up the actual rail and recycle the materials, future rail could be replaced by roads that have far higher capacity.The pods can easily guide themselves along the same path without the rails. So without the heavy trains of yesterday, we won't need rails at all. The technologies need developing, but are entirely feasible, and this region has much of the expertise needed to make it work. It would work far better and be far cheaper than what is being proposed. We need to develop small batteries or super-capacitors, inductive charging systems, the protocols, and the pods. But we would really end up with a modern railway for the 21st century, not some patched up Victorian system.




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