Alan James (NCE 2 August) and William Weir (NCE 11 September) have both fallen into the same trap as many others.
The first rule of railway capacity is that the maximum capacity is achieved when all trains run at the same speed and stop in the same places. Any variation in speed or stopping capacity and capacity reduces dramatically.
The West Coast Main Line tries to run four types of trains on two sets of tracks: local passenger trains stopping everywhere; semi-fast passenger trains stopping at intermediate stations like Northampton, Milton Keynes and Stoke; express passenger trains stopping only at key stations; and freight trains.
In recent years the problem of capacity has been eased by reducing the semi-fast trains to the justified complaints of those who live in places like Northampton and Milton Keynes.
To increase capacity another set of tracks are proposed - but what type of train do you remove from the existing tracks? If it is for local trains the route is fixed and many communities will be impacted.
At the opposite end of the spectrum the express trains provide the least number of constraints and so the impact is minimised. So what does this do for the people who use the intermediate stations?
Well once the non-stop express trains are off the existing lines there is much more capacity for the semi-fast trains. They will therefore benefit from the much greater capacity on the existing tracks where trains will be moving much closer to the same speed.
If no extra capacity is provided then it is these places that will lose out. If the new capacity is compelled to stop in these places then the capacity is still reduced and existing communities will be impacted by new construction.
- Nick Orman, email@example.com
Your correspondent William Wier (Letters 11 September) mentions “the [HS2] tail wagging the dog”, and offers an interesting suggestion. However, I feel that he (and many others involved) appear to still be stuck in the 19th century.
I read with interest the paper on Heathrow Airport’s Personal Rapid Transport (Civil Engineering Proceedings, Vol. 167, Issue CE2 May 2014). I note that the DLR has been running driverless trains for many years. I note, too, that, in space, they have been docking vehicles for years.
Taking his suggestion the logical step forward into the 21st century, here is my suggestion:
Your train starts at Euston, with (say) 10 powered coaches. It accelerates at (say) 0 to 60 in 15 seconds, and on up at the same rate to its design speed of 225mph, which it achieves after about a minute, having covered about 5.6km.
After 98km (16 minutes) the last coach is detached, and brakes to a stop at Northampton, about a minute after the main train itself has hurtled through the station at 225mph.
This process is repeated at Birmingham (190km from Euston, 32 minutes) Stoke (262km, 44 minutes) Manchester (333km, 55 minutes) Lancaster (416km, 69 minutes) Carlisle (521km, 87 minutes) Glasgow (675km, 113 minutes). The train on arrival now comprises only four coaches, having shed one at each station on the way.
Meanwhile, the first coach that was dropped off at Northampton dwells there for two minutes, then sets off again, and reaches the 225mph, before coasting in to Birmingham (arriving some 5 minutes after the train has gone through), where it links up with the second coach which has been waiting there for three minutes. And this process continues all the way up the line, serving every station en route, and arriving some 23 minutes after the first part of the train.
This gives the best of both worlds - a high speed non-stop service between Euston (and Glasgow) and each of those six intermediate stations, as well as a high speed (but stopping) service between them.
Passengers could sit anywhere, just moving into the rear coach to alight at their own destination. Note that strictly there is no need for the rear coaches to be connected together. If they are all “pushing”, then there would be no gap until separation.
We have the technology (this only involves undocking at speed). But have we the can do spirit that the Victorian engineers had in abundance? Or are we too hide-bound by regulations?
- Robin Clay (M), firstname.lastname@example.org
Solution to M25 woes may lie in London Ringway
As a graduate engineer living in South London but seconded for a period of time to an office in South Mimms I have extensive use of the M25, like many readers I imagine. My journey should have been 1 hour 20 minutes and at 6am that was possible, but returning home at 5.30pm it was a two hour trip minimum. After two weeks of this I refused to do it and instead travelled 2 hours on a train and undertook a 3km walk across country to get to my place of work. It’s telling that I preferred this route to driving on the M25.
As you point out, the section around Heathrow, where the worst of the congestion is, the road is already five lanes wide and a smart motorway controlled by gantries and cameras. Maybe the answer lies not widening the existing road but in other orbital roads like the original London Ringways plan of the 1960s? London Ringways was an ambitious but destructive plan to build up to four concentric orbital roads around the capital. Maybe having alternative routes around the capital or certainly parts of it would reduce congestion on those sections that are extremely unpleasant to drive on.
- Adam Kelsall, email@example.com
Renewables do not offer reliable supply
You are obviously right in your editorial of 11 September to emphasise the impending crisis over power generation. But I do not see why there is such support for photovoltaics.
Whether photovoltaic panels are floating on reservoirs or covering productive farm land, they still stop producing when the sun goes down and will give poor value in the short overcast days of winter, when the power demand is greatest.
We need to put much more emphasis on storage. This may involve tidal lagoons, radically improved battery performance, or mass-generation of hydrogen at off-peak times. But we shall still need the flexibility of fossil-fired generation.
- Mike Keatinge (M), Highbank, Marston Road, Sherborne
Yes, widen the M25, and a host of other roads
You ask “Where to, now that the widened M25 is full again?”
The short answer is build London’s outer ring like the A86 round Paris, joining up all the circumferential lengths of dual carriageway 60km out.
From the Lower Thames Crossing (to come), to Maidstone, to Tonbridge, to Gatwick, to Farnham, to Bracknell, to High Wycombe, to Tring, to Welwyn Ware, Bishops Stortford, to Chelmsford and back to the lower Thames Crossing.
The long answer is you don’t start from here with 15 years of sticking plaster widening, or so-called widening of existing motorways, which will need revisiting in 10 years’ time.
It is never too late to get the right answer and with politicians waking up and much more money available for infrastructure we should aim for a proper road network.
So let’s get on with, a duplicate M6 Birmingham to Manchester, dualling the A303 and A47, complete the south coast dualling from Ashford to Southampton; the M65 through to the M62 at Bradford, complete the M67 to Sheffield and finish making the A1 motorway all the way to Newcastle, announced 30 years ago.
This lot will do for a start. We then might have a basic flexible network with options in times of trouble and an overall increase in capacity.
- John Franklin (F), 11 The Ridings, East Horsley, Surrey KT24 5BN
Warwick is a champion of tunnelling
Richard Coakley highlights the sustained need for tunnelling skills over the next 10-20 years in the UK (NCE 11 September). He mentions the Tunnelling and Underground Construction Academy which, if it continues, will help meet the need for skilled operatives, but he did not mention the corresponding need for specialist tunnel engineers capable of designing and managing these projects.
We cannot rely on importing skills because growth in tunnelling is not restricted to the UK.
Three years ago the British Tunnelling Society set up an MSc in Tunnelling and Underground Space at the University of Warwick and have supported it through bursaries, site visits, prizes and guest lectures.
So far we have produced 33 excellent graduates, all of whom are now working in the tunnelling industry, mainly in the UK. Word about the course is spreading, applications have risen year on year and we are expecting 20 students to commence their studies with us this October.
- Benoît Jones (M), principal teaching fellow, director, MSc in Tunnelling and Underground Space School of Engineering, University of Warwick, CV4 7AL