ZING ~ The Incredibly Light Railway. Part 2.

A couple of weeks ago I wrote the first part of this series about our proposals for ultra light railways.  If you haven't, please read it first.  Today, writing in The Observer, Ed Miliband said, "As the Intergovernmental Panel on Climate Change has said, if the world is to hold warming below 2°C, global emissions need to peak not long after 2020 and then decline rapidly to reach net zero in the second half of this century. The weaker the action now, the more rapid and costly the reductions will need to be later. I do not want to see Britain or any country having to adopt crisis measures to halt the slide into global catastrophe because we missed this critical opportunity now."

So let us accept that by 2050 there will be no fossil fuel used for transport, public of private.  Beyond a little biofuel, the options will be walking, cycling and motors using renewably generated electricity. That said, let's take a further look at Zing ~ The Incredibly Light Railway. People who have commented on the proposals frequently talk either of disability access or of cost. The first is easiest to deal with.

The proposed trains are made up of carriages that seat people in twos side by side, like motorcars, three or four pairs facing to one end and three or four pairs facing the other end, but in the middle there is a space without seats big enough for two wheel chairs or mobility scooters or some bicycles. There would be no step from platform to carriage so they could roll easily aboard. It’s interesting to note just how many people’s first thoughts are towards disability access, a positive reflection of our times perhaps. The provision of bicycle space, however, is also important as it is the last link in the journey that makes private cars so much more convenient than public transport. Passengers need to be confident of being able to take their bikes with them, as even with the relatively dense rail network proposed, many people’s destinations may not be an easy walk from the station.

The cost is trickier. First let’s set up a bench-mark. In June 2013 the government estimated that the 192 kilometres (119 miles) of HS2 Phase 1 from London to Birmingham would cost £22 billion. Many commentators believe the final figure will turn out to be considerably higher, but let’s use the government’s estimate for now.

In 1914 we had 37720 km (23440 miles) of railways, now there are just 16753km (9788 miles). If, instead of spending the £22 billion on HS2, it were spent on reinstating the lost 22000 km as Ultra-Light Railways then there would be £1 million available per kilometre. That’s more than enough to rebuild every last little branch line that ever there was.

Or it would be if that figure of a million pounds per kilometre is in the right ball-park. So this is where, dear reader, we need your help. Just how much will it cost?

A big saving is in the cost of land acquisition since Zing’s footprint is rather small, at least when compared with HS2, which runs on a 25 metre wide fence to fence vegetation free zone (how much herbicide is that going to take?) and then a further 25m either side of restricted vegetation, making a 75m wide footprint in all and so using 7.5 hectares per kilometre of track. Zing only requires about a five metre width, half a hectare per kilometre. If the price paid for acquiring agricultural land is, say £25000 per hectare, then the comparative costs of HS2 and Zing are £187500 and £12500, a 15-fold difference. Actually the difference is far greater. Instead of running on the routes of closed railways that are still by and large free from buildings, HS2 cuts virgin territory and since it can only have extremely large radius curves there is little opportunity for avoiding expensive real estate by deviating the line, whereas the Zing route can be adjusted to miss most buildings and costly infrastructure. Land purchase, at about £3 billion, is a significant part of HS2’s cost.

The costliest item on the government HS2 shopping list is “Tunnels, including ventilation and drainage, and Bridges including viaducts and other structure”, coming in at well over £6 billion. In this area Zing scores dramatically. Few or no tunnels will be needed and bridges can be simple and cheap affairs since ultra-light weight is the essence. The low headroom required by the carriages means that where roads go over the railway, bridges can be very low; no call for heavy engineering or even the old-style hump-backed bridge. Very many bridges built for the original railways are still in serviceable condition, especially for traffic that will be much lighter than the original structures were designed for.

The roughly £1 billion to be spent on diverting existing utility cables and pipes en route from London to Birmingham will not be required in the case of Zing. HS2 requires almost £5 billion in new stations and other buildings. Most Zing stations, and there will be a lot of them, are very simple affairs. The small wheels and low ride height of the trains mean that platforms worthy of their name are hardly necessary. Rather there will be a slightly raised pavement to allow wheel-chair access with no step up into the carriage. But let’s see what we can do with £5 billion to spend on stations. With 20000 km of new railway let’s put a station every 2km, so that’s 10000 stations. We have £0.5 million to spend per station. But since the vast majority of these stations will comprise little more than a couple of strips of paving, a sign board and a flower bed or two, there should be quite a lot of change available.

Another large expense for HS2 is the power supply infrastructure, the overhead cables.  They also don't look too pretty.  The ultra-light weight of Zing allows the use of modern battery power, a 21st century technology for a 21st century railway rather than using the 25kV AC overhead system introduced in Britain in 1956.  Train batteries will be charged overnight but boosted by induction charging whenever the train stops at a station.  This is a technology still in its infancy but several prototypes are being tested on buses in various countries. Examples: Milton Keynes, Utrecht, Netherlands, MannheimGermany, Gumi, South Korea. 

By mid-century with the zero net carbon emissions policy enacted, there will be plenty of competitive demand for renewably generated electricity so any opportunity to produce more should be investigated.  The space between the rails, over a metre wide, is unused and unproductive on all current railways.  Fill it with photo-voltaic panels.  There's 2000 square metres available per kilometre of twin track railway.  Using today's mass produced solar panels (and power density is set to continue increasing) one might expect to generate 100000 kWhr per year per kilometre.  That's perhaps not enough to run the railway, but it is a major contribution.  The Utrecht electric buses use about 1.2 kWh/km. Running one of those every 15 minutes for most of the day would only use 40000 kWhr/year/km.

The cost of rolling stock is a significant item, especially for HS2, currently estimated by government at £7.5 billion.  How much would Zing trains cost? For such a light-weight innovative vehicle, rather than looking at the cost of conventional trains, comparison with the Tesla electric sports car may be more valid. They cost about $100000 each.  They are smaller than Zing's carriages but more complex.  Let's assume, for the sake of discussion, that Zing carriages

cost £100000.  That should be generous enough to allow for the automated systems of driverless operation.  If we run trains of ten carriages they cost £1 million per train.  The £7.5 billion rolling stock bill for HS2 thus pays for 7500 trains, or more than enough to put a train on every three kilometres of the 20000 km of new railway.

Of course many of the figures used here are very rough guestimates, but they indicate that for the cost of building HS2 we could rebuild a dense network of ultra-light railways replicating the 20000 km of line lost since the British system was at it's maximum just before the First World War.  As Ed Miliband said, let us not miss this critical opportunity now.

continued in Part 3