I am grateful to your correspondent professor LJS Lesley for his comment regarding my “optimism” regarding the acceleration rate of trains (NCE 9 October).
He suggests two minutes to reach 60mph. A train driver told me that today’s rate is 195 seconds to reach 160km/h (I’ve done my research); the Shinkansen N700 does 0 to 96km/h in 37 seconds.
However, firstly, I drew my figure “out of the air”, without any intention that the actual figure should be regarded as sacrosanct; and, secondly, presumably Lesley’s figure is applicable to today, whereas I was thinking of the future - High Speed 2 (HS2) will not be carrying trains for some years yet, by which time acceleration rates are likely to be faster than his figure.
I am also grateful for his mention of the fact that the technology I suggested has already been used successfully. The reason for its demise, I suspect, was due to each slipped car needing a driver, and drivers are expensive. They won’t need drivers on HS2.
And I did like the picture accompanying his letter. At about that time, as a small boy going unaccompanied to school (a five-day journey on a steam train in Africa, average speed 40mph) I would sometimes, when the train stopped, place a penny on the rail in front of a wheel. When the train started, I would wait for the second wheel of the bogey to go over the penny, then snatch my flattened trophy and climb aboard. The acceleration rate allowed this. Average speeds and acceleration rates have improved since then; I am sure they will continue to do so.
- Robin Clay (M), email@example.com
Robin Clay’s suggestion of coach-slipping, and professor LS Lesley’s response to it, appear to pay no regard to either the physical possibilities nor the practicalities of the idea.
Firstly, the service would be asymmetric in that a journey from, say, Euston to Stoke could be “slipped” with no stops en route, but the return to Euston would have to be all stations as there’s no way a slipped coach could catch up with an express that has passed.
Secondly, the power units to drive trains up to 300km/h or more cannot be accommodated within the power bogies (as in a conventional EMU) and a significant portion of each ‘slip’ carriage would need to be devoted to motors, blowers, and other electrical equipment needed to accelerate even a single carriage to high speed.
Thirdly, high speed trains need to have an air-smoothed front end that would prevent use of the front portion of the carriage, but it would also make inter-carriage connections complex to design and operate.
Presumably the rear end would have to be similarly air-smoothed for shuttle working.
I can’t imagine the kerfuffle that might prevail in a carriage connection when people are obliged to move carriages quickly because they want to get off at the next ‘stop’ and have sat in the ‘wrong place’: this would be even worse with a mobility impairment, large travel bags, prams, dogs, or wheelchairs. I guess seats could all be allocated in advance, so you have to turn up 30 minutes before departure to ensure you get in the right place - in which case, why the high speed?
This is utter nonsense, so please can we have reality checks on ideas like this - it’s not as if we are thinking of slipping the odd carriage off the end off of a relatively slow-moving steam-hauled train in the 1950s.
- Geoff Bruce , 37 Eachard Road Cambridge CB3 0HZ
The recent letters about slip coaches are from the viewpoint of travel choice from a rail hub, presumably London, from which it is true a range of destinations could be offered with reduced intermediate stops through choosing the slip coach for your intended destination. However, from the viewpoint of ‘the rim’, or for those wishing to travel between two intermediate stations on the route, the choice of destination would be seriously restricted.
The same London-centric perspective creeps into the case for HS2. In both these discussions it should be realised that there are just 346 stations in the London travelcard area and the total number of departures from all of these was 614.8M in 2012/13 (the most recent year for which Network Rail footfall figures are available).
On the rest of the network there are 2,537 stations and the total number of departures from these stations in the same period was a larger 654.2M.
However, as the rail system develops, we should not forget it is a network and not everybody - in fact only a minority, perhaps disproportionately vocal - is travelling to or from London.
- Michael Willmot, firstname.lastname@example.org
SuDs need to have financial guarantees
Daniel Hayes correctly speculates that developers choosing maintenance providers for sustainable drainage systems will lead to a disparate array of surface water provision to be maintained by commercial companies who cannot be guaranteed still to be in business when the first serious maintenance issues arise (NCE 9 October).
The local planning authority must ensure that maintenance is provided but how will it deal with bankruptcy or other forms of default in either the developer or the maintenance provider when it appears there will be no facility for a bond? A planning condition alone cannot achieve this.
In 2011 the wastewater network was brought under a simple unified regime. Schedule 3 of the Flood and Water Management Act 2010 proposed something very similar for surface water infrastructure.
This takes surface water in the opposite direction and should be resisted vigorously by those on whom the burden will fall when it fails.
In the consultation there is only one viable option for maintenance and that is to place it with the water and sewerage companies within their regulated business where it can be provided at nominal cost.
- Howard Glenn (M), email@example.com
High hopes for Wikihouse low voltage
I was impressed with the self-design prefabricated timber house featured in NCE on 9 October, even though the “wiki” prefix didn’t immediately fill me with confidence.
Moreover, I was interested to read about the low voltage DC circuitry used in the house.
I have long thought that a 12v DC circuit would be beneficial for domestic use for two reasons.
One being the increasing number of electrical appliances that use internal or external transformers to convert from mains AC, wasting energy
in the process.
The second being the growing use of solar panels and wind turbines to generate electricity which need an inverter, also losing efficiency, to feed into the grid.
I think a 12v system backed up by something as simple as car batteries fed by a combination of individual generation and a single mains transformer could provide a better solution.
- Quentin Brogdale, firstname.lastname@example.org
Wikihouse builder needs safety lesson
I was very interested to read your article on the latest Wikihouse design. I was, however, disappointed by the photo on the front cover which showed what appeared to be a volunteer working at height from a step ladder and handling timber elements without gloves.
- Adam Ray (M), email@example.com
How much is a degree really worth?
The recent “fact of the week” illustrating graduate starting pay for civil engineers being the lowest of all engineers is not so daunting a fact as what happens for their rest of career.
Their pay barely doubles for most after they reach their technical peak.
Consider the high cost of a four year degree (£80,000 all in) and the rewards thereafter (a lifetime average remuneration £40,000 per year).
These points seem to escape the Crossrail-type employers craving to recruit for the future but are so important to avoid that looming skills crisis.
We have a wake-up call yet to be sounded for both those in work (some tired and cynical) and those youngsters aspiring to become professional engineers.
Students who have been told at college of a “rewarding” profession with salaries commensurate to other professions to repay their tuition fees and costs may be disappointed and disheartened.
Sadly, monetary considerations might be a much bigger factor now than before, and today’s enlightened youth could be swayed from an engineering career path unless its remuneration levels are significantly improved.
Having spent the £80,000 to get a footing on the professional civil engineering ladder, eventually the question they may ask is “was it worth it”?
- Frank Shannon, firstname.lastname@example.org
Flexible working has made all the difference
The recent article on flexible working made for a very interesting read for me.
I have a two and a half year old and the flexible working offered by my employers has allowed me to return to work full time so I am still able to be successful in my career and also at home.
This is achieved by a flexitime type system. I think the change in law to allow all workers the right to request flexible working should be welcomed.
A happy workforce means a productive workforce.
I am personally much happier at work knowing my time there suits my lifestyle than if I was restricted and presented with a much more rigid arrangement.
- Gillian Wood, email@example.com