IEP - how not to design a train

This is the standard 88 seat intermediate IEP vehicle. As I predicted, the seats will be crammed in, and mostly in the unidirectional arrangement. A Swedish survey showed is preferred only by about 30% of passengers. Many of the so-called window seats will not be window seats, including those in the facing bays, which are perfectly placed with a solid panel directly in people's line of vision. That adds up to an unsatisfactory travel experience for a lot of people.

There is only one toilet for all this crowd. Note too, the shortage of luggage space - by the exit, where people will not be able to supervise it. Aren't we constantly being reminded to keep our luggage with us at all times? There was a notorious case when a thief who exploited the possibilities discovered that the suitcase he had stolen contained an IRA bomb. Only a few months ago, a couple of men were convicted of theft of passengers' luggage. Yet the problem is still not addressed, and this on trains which could be in service towards the end of the century.

Yet again, the designers have got it all exactly wrong. Pity the poor passengers. So what is the right way to design a railway carriage? First of all, work out what the length should be, bearing in mind that the longer it is, the narrower it has to be. The widest permissible width on Britain's railways is around 2.8 metres, a full 20 cm less than the width of trains in many parts of Europe. That cannot be helped, but it does mean that the vehicles should not be stretched unduly. 20 metres gives all the permissible width, the 23 metre mark 3 stock loses about 7 cm, and it gets progressively worse after that. The 25 metre IEP vehicles will actually be 2.75 metres wide, slightly more than mark 3 but either that means route restrictions, or a lot of money to be spent on gauge enhancement, or that a new method has been used to calculate loading gauge tolerances. Whichever is the case, this is almost certainly not an optimum length, that being probably around 22 metres.

Having decided the length, the next task is to work out the bay dimension. 2 metres is desirable and that is the standard on trains like the Danish IC3. 1.8 metre bays are good enough for commuter trains such as the Electrostar but otherwise is on the tight side. Mark 1 stock had 1.93 metre bays but a lot of space was taken up by traditional upholstered cushioning. Mark 2 stock had 1.95 metre bays which was generous, especially with the thinner type of upholstery with ergonomic seating that was fitted to them. Class 180 Adelante stock has 1.90 metre bays and it is generally agreed that these are amongst the best recent inter-city designs to appear in Britain.

Having decided the bay dimension, there are no further decisions to be made. The majority of seats should be in a facing bay arrangement with a table. Nor should there be any need to change the seating layout throughout the lifetime of the vehicle. The only distinction between first class and standard class should be 2+2 seating in the standard class and 2+1 in first, though a few side-corridor coaches would probably be appreciated both by first class passengers and standard class passengers travelling in family groups. That way, the families can sit together and their children are not going to disturb anyone.

There are two important benefits in this seating layout. The first is that it creates space between seat back, where people can keep their cases in sight throughout their journey. The second benefit is that if seats are arranged in facing bays, each pair of back-to-back seats can be designed as a structural unit. This avoids having to provide individual seats with heavy, crashworthy frames. With several dozen of them in a vehicle, the build-up in weight is considerable. This was discovered when the lightweight British Rail seats were replaced by new ones in a fleet of 1970s suburban EMUs, which then had difficulty in keeping time to the previous scheduled as the units became under-powered.

Economies in areas away from HS2 could suffer big losses.

The government has been accused of attempting to suppress the drawbacks of its flagship transport project after previously unseen research revealed cities across the UK could lose up to £220m each as a result of HS2. The KPMG study, commissioned by the government, predicted more than 50 areas would be worse off as a result of the high-speed rail project – including Bristol, Cambridge and Aberdeen.

Read article in The Guardian.

The tide is turning

At last, an increasing number of politicians and commentators are coming out against HS2, essentially for the reasons which have been repeatedly stated in this blog. The NIMBY lobby as at last lost its dominance in the debate to those who are arguing the real economic case against the scheme. It is not that the country cannot afford it. The scheme is just a bad way of spending the pot of money.

Some of the opposition is from the roads lobby, which wants a share of the cake. The sad thing is that nobody has even now come up with costings for what is really needed to increase the capacity of the railway infrastructure, which would be a combination of upgrades of existing routes and the construction of some new conventional-speed routes, essentially on the alignment of HS2, which at the southern end is mostly on the former Great Central route, but with a lot of expensive straightening-out to cater for the higher speeds. With a conventional speed railway, this new construction becomes largely a matter of replacing the track on the old trackbed, electrifying and installing an ERTMS signalling system. That is a far more cost-effective proposition than HS2.

HST cost could hit £73 billion

Treasury officials are privately warning that the cash cost of the controversial High Speed 2 rail line will hit £73bn. FT article

Is this a joke?

The new Thameslink trains from Siemens look like a near-copy of the old and unloved class 319 Thameslink train from BREL, apart from the even uglier front end and the lower bodyside curvature which will reduce the width at floor level. The doors and windows appear to be in exactly the same place. Why on earth didn't they just order some more class 377 units from Bombardier and avoid the row over the loss of jobs at Derby? How much did it cost in consultancy to develop this specification?

Expensive mistake warning over HS2

See FT article here. As the price estimate is revised upwards it looks as if the message is beginning to sink in.

Göteborg's unconvincing rail project

Västlänken is a 20 billion kronor project designed to join the railway lines running north and south of the city, where all routes currently terminate at the Central station. It is mostly in tunnel and coloured green on the map. It goes round three sides of a square, though it is claimed that due to easier tunneling conditions it would be less expensive than a direct link.

It will not make for fast through-journey times. Nor does not look like the most cost-effective solution to the problem of saving people travelling from north to south the trouble of having to change at the Central station (red on the map).

One aim of the route is to bring rail services into the western side of the city centre with a new station at Haga, but connections to this part of the city centre could be improved at a fraction of the cost, and again, much more quickly, by extending the existing tramway, which now runs through the city centre, to run along the inner ring road direct to the Central station.

The proposed scheme will certainly work but there appear to be alternatives which would achieve most of the benefits at a fraction of the cost, and which could be completed much sooner.

National Audit Office expresses its "doubts" about HS2

The National Audit Office has issued this report. "Doubts" is code for total demolition of the economic case for the project.

New class 68 fleet under construction

The Railway Gazette reports that The first of 15 Vossloh UKLight diesel-electric locomotives for freight and charter train operator Direct Rail Services is now under construction at the Vossloh España plant near Valencia in Spain. DRS expects the first locomotive to be sent to the Velim test circuit in the Czech Republic for trial running in September, and the second to arrive at DRS’s Crewe depot by the end of October to start the UK approvals process.

Designated Class 68, the UKLight is based on the EuroLight freight and passenger locomotive family. Intended for both freight and passenger operation, the 21·5 tonne axleload Bo-Bo will have a 2 800 kW Caterpillar C175 engine and AC traction equipment supplied by ABB. Differences from the EuroLight design include a smaller-profile to suit Britain's more restricted loading gauge, a higher top speed of 160 km/h rather than the 140 km/h and an increase in fuel tank capacity from 4 000 litres to 5 000 litres.

The Class 68’s mixed-traffic capability means that it is likely to undertake a wide variety of duties for the operator. DRS says it would be capable of ‘at least matching’ the performance of its EMD Class 66 fleet. DRS also remains hopeful of expanding its passenger operation, which is currently focused on the charter train market. It is in negotiations with the Department for Transport and franchised passenger operator Northern over the potential launch of scheduled passenger trains along the Cumbrian Coast line in northwest England.

The styling is to say the least odd, with a reduced width to the front of the cab that apparently serves no purpose whatsoever - on the contrary, it positively prevents the driver from looking out of the window to obtain a view back along the length of the train.

At 3700 hp, the locomotive is significantly more powerful than the 3300 hp Deltic and roughly equivalent to what the 8P Duke of Gloucester would be if the remaining teething troubles with the locomotive, completed in 1954, were finally resolved. Unfortunately, the latter machine is currently out of service awaiting overhaul. Given that the production cost of a batch of steam locomotives is about one-third or less of that of the equivalent diesel, and the work done by Roger Waller in demonstrating how steam can be integrated with surprising ease into the contemporary railway environment, it is infuriating to see a potentially promising technology is still being sidelined due to perceptions that it is "old fashioned".

A Thatcher legacy

Canary Wharf Station, originally uploaded by Elmar Eye.

The Docklands Light Railway is a curious legacy of the Thatcher period, when London Docklands was designated as an Enterprise Zone. These Zones were a brainchild of planning minister Michael Heseltine and offered planning and tax concessions.

The DLR opened as a Y-shaped route from Tower Hill to Island Gardens, at the north end of Greenwich foot tunnel, and to Stratford, mostly on long-closed railway alignments. Extensions were built first to the Bank, giving it an interchange to the London underground system, and then to Lewisham on the south side of the river, to Beckton to the east and to Woolwich, again on the south side of the Thames. The Lewisham extension was expensive for what it was, involving a long viaduct, diversion of the river Ravensbourne, and burrowing under the railway embankments at Lewisham, to a terminus on the wrong side of a busy roundabout separating it from the main town centre.

Standard overhead electrification was not used, for aesthetic reasons, and an unusual system of bottom-contact third rail electrification was used instead. The trains were fairly conventional lightweight tramway-type vehicles. Driving was automatic ie from the control centre, and the member of staff acted as a general order-keeper and driver in emergency.

The system quickly proved inadequate. The fleet has been replaced three times. Trains have had to be lengthened and stations rebuilt to accommodate them. The system was never going to have the capacity to serve the commercial development at Canary Wharf, and eventually, with a contribution from developers Reichmann, the Jubilee Line Extension was constructed from Bond Street to Stratford, giving through services to Stanmore in north London. One that was open, the development of Canary Wharf could go ahead.

The system gives the impression of being clean and well run and obviously serves a useful function. Whether it is the system that would have been built had it been planned from the start is another question. Due to the larger size of the trains, the tunneling - and there has been quite a mileage built over the years - was considerably more expensive than if some of the line had been built as a tube. Other parts of the route would, more logically, have been developed as conventional railways run with conventional stock, and eventually integrated into London Overground. Other parts again - perhaps the Lewisham route - would probably have been more useful if they had been constructed as conventional on-street tramway, which could then have gone on to Catford and Bromley and perhaps eventually have joined up with Croydon Tramlink. The Jubilee Line Extension would probably have taken a different form if the DLR had opened as a direct tube line from the Bank to Canary Wharf and Stratford. Such a route would also have been more easily extended westwards from Bank, an enhancement which remains on the list of aspirations for the DLR.

Hindsight is a wonderful thing, but already in the early 1980s planning was out of favour in the political right, especially longer-term planning. There was a desire to spend as little as possible at the start. The system, whilst quite good in its own right, is almost certainly not what would have been built if it had been planned from the outset, nor can it have been particularly good value for the money it has cost.

Were the standards a waste of money?

Toddington - Gloucester and Warwickshire Railway, originally uploaded by Elmar Eye.

An article in this month's Steam Railway discusses the standard fleet of British Railways steam locomotives built to new designs between 1951 and 1960. There were 999 of them, and all were out of service by 1968, so they were not good value for money. Were British Railways' engineers to blame?

The story is long forgotten, but, as the article reminds us, the British Transport Commission had a sudden change of plan in the mid-1950s and diesel locomotive types which were on order in small numbers for comparative trials were ordered in large numbers before the test locomotives had even been delivered. This change of plan was imposed on the horrified engineers. Whole fleets of the diesel locomotives were effectively prototypes and the engineers were saddled with the task of resolving the teething troubles. In the case of some of the classes, the teething troubles were never resolved and the expensive hardware - typically costing five times as much as the equivalent steam locomotives - went to the scrapyard even faster than the "Standards".

Thus, all the planning that had been done to supersede steam traction in an orderly way was set aside and dieselisation was conducted in a rush. In France and West Germany, steam remained in use for another ten years or so.

The article suggests that had economic considerations applied, the locomotives would have continued in service until the early 1990s, as intended. What the article does not mention in the article is that, as information has come to light both through research, release of documents and experience of the locomotives in preservation, they were exceptionally well-designed both overall and in detail, being almost free of inherent flaws. The 8P Duke of Gloucester and the 9F 2-10-0 were an outstandingly good designs. They would have had particularly long service lives.

They would then have retro-fitted with the technical improvements developed by Porta, Wardale and Waller, that took place from the mid-1970. In that case they would probably still be in service on secondary routes currently operated by Sprinters and Pacers, as well as on infrastructure trains where long periods are spent doing nothing at all. In fact, it is not impossible that additional locomotives would have been built to replace the original standards as they wore out.

That said, 12 different types was undoubtedly too many. Was there really a need for the 8P Duke, and the Britannia, and the Clan class and the class 5? Or for the class 3 tender and tank engines in-between the class 4 4-6-0 and 2-6-0 types, and 2-6-4 tank, and the class 2 2-6-0 tender locomotive and the 2-6-2 tank.

It is good to see this deplorable series of events brought to attention. It is an excellent illustration of the expensive damage that can be done through political interference.

How the real case against HS2 has been buried

The economic case against HS2 has scarcely featured in public debate, which has mostly focussed on the harm it will do to well-heeled residents in Chiltern villages. One explanation is now surfacing. A lobbying firm employed by the government to promote the case for the High Speed 2 railway line is at the centre of a row after its founder, a Tory-supporting peer, was accused of painting opponents of the scheme as posh nimbys worried about their hunting rights.

Read more in this Guardian article here.

Vehicle interior designs

RT8 top deck interior 03/08/10, originally uploaded by Ledlon89.

Why have things gone so wrong since?

Do 26 metre vehicles give higher seating capacities?

I have tried without success to convince people that the proposed IEP length of 26 metres is too long for vehicles on the UK system.

One of the arguments being put forward for the extra length is that the seating capacity of a train is higher if the vehicles are longer. I would have expected this but when the calculations are done I am left wondering.

So what is the difference in the number of seats between 12 x 22 metre vehicles and 10 x IEP vehicles, of almost identical length? To make a fair comparison you have to assume equal seating density. Because the IEP has its luggage space outside what can be termed the "furnishable area", when it can actually be between seat backs within the furnishable area, this comparison is not so easy to make. However, furnishable area is a fair proxy.

The furnishable area in a 22 metre vehicle can be taken as 17.1 metres, the rest of the space being occupied by a toilet, luggage shelves, vestibules and a total of 1 M crumple zone. This gives a the total in 12 vehicles is 205 metres.

What about the IEP? IEP-TECH-REQ-35-Issue 05 (Technical specification for IEP published by DfT) states: "As a minimum the Furnishable Space length shall be 144m for a nominally 208m long IEP Unit."

That is 8 cars, which suggests the average furnishable space in an IEP vehicle is 18 metres. But there are two driving ends in the 8 car set, and that suggests that an intermediate vehicle will have 20 metres of furnishable space, perhaps 21.5  metres at the most. Which adds up to 200 to 215 metres in 10 vehicles. In other words there is no significant difference. That surprises me.

My own preference would have been either articulation or to have the longest vehicle that was possible with an external width of 2.80 metres with a go-almost-anywhere capability. Allowing 1.90 metres per bay, that gives a 9 bay vehicle (17.1 metres) with a further 1.2 metres for a toilet ie a total of 18.3 metres. A wheelchair access toilet can be provided in a vehicle with 8 1/2 seating bays. You then have 2 x 1.2 metres for the vestibules and a further 2 x 0.5 metres for crumple zones.

26 metres would be nice to have but it would need a new railway to fit them in without undue compromise.

HST phase two announced

Comment and analysis here. This reinforces the argument if there was going to be a high speed line at all, it should have started from Scotland and the North of England.

The railways as political football

Great Central Railway Loughborough Leicestershire 26th January 2013, originally uploaded by loose_grip_99.

Few people alive will remember this striking colour scheme which was introduced when the railways were nationalised in 1948 but had disappeared by 1954. It distils the mood of post-war optimism - the belief in a better future after the austerity years. The engineers of the time were both forward-looking and backwards-looking. The colour scheme was a revival of the Caledonian Railways livery previously last seen in 1923, and it actually popped up again in 1960 when the Glasgow suburban railways were electrified. The trouble with the blue, and the red and cream colour scheme for the carriages, was that it needed attention which was not forthcoming in the post-war years of labour shortage. So the blue was replaced by a dark green and the carriages went into maroon, a dignified though muted scheme which was enhanced by a heraldic badge. It all seems very distant now, when colour schemes are devised by public relations companies and applied as stick-on vinyls.

But the post-war railways were not a stick-in-the-mud outfit. There were experiments with diesel traction both for local and main line use. British Railways was a pioneer in the development of the now standard 25kV 50Hz system of electrification, with the conversion of three old trains fitted with amongst the very first solid state high power rectifiers, made of germanium, a rare and expensive element. A coherent modernisation scheme was put together, with the aim of electrifying all the main lines and the busier suburban routes and using diesel-electric traction as a stop-gap. Rail-buses were to be used on routes with light traffic. To give an indication of the rate of change, it was expected that steam traction would finally disappear in the mid-1980s, and so construction continued until 1960.

As things turned out, it was all very different. The railways became a political football. The evolutionary approach was abandoned. Under government pressure, the railways were instructed to order, in large numbers, diesel types intended for pilot-scale testing. Whole fleets suffered from the inevitable teething troubles. Modern, almost new steam locomotives went for scrap. Main line electrification proceeded slowly. The railways were stuck with diesels. The line from London to Edinburgh was not completed until 1992, and electrification of the Great Western main line is only now beginning. There are no current plans to electrify other important routes such as the Great Western line from London to Birmingham and Bristol to Birmingham.

Then came Beeching and a huge trimming back of the system, the un-wisdom of which is only now being recognised.

Of course the subsequent story is not all bad. There have been some successes: the long-lived HST, not my favourite train but it has done sterling service. The BREL development of the International Train, which unfortunately did not become a standard. And the much maligned Leyland railbus - which has also given 25 years of useful work on secondary routes which, when the bottom line is all that matters, would have probably lost their services altogether

How much innovation?

How fast should railways innovate? The Advanced Passenger Train came about when British Rail imported a team of engineers from the aerospace industry. As an experimental project it was a success. But the aim was to introduce these trains into fleet operation. Fortunately a group of old school BR engineers had their own ideas of pushing mature technology just a little and were not prevented from pursuing them. The result was the HST and still no-one has actually got an effective replacement into service. And the HST itself had its share of teething troubles which went on for years.

But if we relied on only ever building what was safe from any risk then we'd be running a railway which didn't look much different from that in the 60's. Or would we?

Steady evolution or evolution by leaps and bounds?
The first 80 years of railways were dominated by steam power, which continued to play an important role until the 1950s. There was a steady development and a steady increase in power and performance, but attempts to move even marginally away from the mature technology of the time were a failure. Most improvements arose as a response to the deficiencies of the mature technology, resulting in steady evolutionary development.

Then came the introduction of electric traction from around 1900 onwards and that involved the application of robust mature technology and steady evolutionary progress, with DC or low frequency AC motors. These were  acceptable for short distance routes, but the shortcomings of power cars - poor ride quality - were an issue that was not resolved until the 1970s.

Electrification was given a boost by the development of improved systems of rectification including solid state devices, which made possible the introduction of 25kV /50 hz systems with reduced costs, and that paved the way for a second wave of electrification of main lines. Again the process was evolutionary and fairly trouble free. In more recent times we have seen the introduction of variable frequency 3-phase motors which have made innovations like distributed drive more feasible. There was nothing new about the concept but it took the development of power electronics to make them practicable. Again, this has been an evolutionary development with lots and lots of testing being done.

Internal combustion was another matter. Locomotives with marine diesels were built quite early in the twentieth century but high powered diesels designed for constant output direct to a propeller and are inherently ill-suited to railway conditions. Direct drive is impossible and expensive electrical transmission systems are needed. As a result, the cost per horse power was five times that of a steam locomotive and for this reason they made little progress until the 1950s.

On the other hand, low powered underfloor engined internal combustion engines with mechanical transmission transferred quite well to the railway environment and were the basis of the fairly successful DMU programme initiated in the mid-1950s. I say fairly successful, because the new diesel trains provided an inferior passenger environment to the steam hauled trains they replaced, and this is a problem that has been compounded in recent years with the development of high speed inter-city DMUs, where the concept is even less suitable when the engines are large powerful units.

Apart from the DMU programme, the transition from steam to diesel in Britain was wasteful and troublesome. Few of the locomotive classes seem to have been really satisfactory and many were short-lived or needed expensive fleet modifications. The country is still living with the consequences today.

In the same period, the cost of rolling stock has increased from around £6000 per hauled vehicle in 1955 to £1 million today (some would say even more). Allow a generous factor of 40 for inflation and that is a real cost increase by a factor of 4. Now whatever else you might say about the latest trains, they are not four times as fast or four times as comfortable or four times anything else that is perceptible to the passenger. Nor are they four times easier to maintain. The might be four times safer but that is not a matter of cost but a result of putting the metal in the right place due to the use of FE analysis, and that was largely sorted out when the mark 3 bodyshell structure was developed. So it looks as if things have gone well past the point of diminishing returns.


An alternative history
What would the railway look like if things had gone the way I would have liked to have seen it go? In the first place, there was no intention in 1955 of getting rid of steam within a decade, as actually happened, very wastefully Thus electrification would have proceeded much faster, with both the ECML and WCML and the Midland being wired by the late 1970s, and the core GW routes following by the mid-1980s, after which the wires would have been extended to places like Aberdeen, Inverness and Plymouth by 2000, as well as linking routes such as Southampton-Bristol. Many of the Beeching closures would not have happened, including such routes as the Great Central and lines in southern England where there were already signs of development pressure.

Speeds would have crept up, mostly through incremental improvements to the infrastructure, however, probably not much above 110 mph. The aim would have been to provide a cost-effective service with affordable walk-on fares available outside the high peak times.

Such a railway is far from the one Britain actually ended up with.

26 metres is too long

 

I have criticised the decision to introduce 26 metre vehicles before, but there could be more problems than just the need to increase clearances. The basic loading gauge on Network Rail remains the C1, which applies to vehicles 20 metres long with bogie centres 14.17 metres apart, and a width of 2.82 metres. These are the mark 1 dimensions, and they are perpetuated in the latest stock built for lines south of London. The C3 loading gauge was introduced in the mid-1970s and allowed the use of vehicles 23 metres long with a bogie spacing of 16 metres between centres. The width was reduced to 2.74 metres, which made them- the mark 3 stock - no narrower than mark 1 stock which had projecting hinges and door handles. Because the bogie centres are 3.5 metres from the ends, it was necessary to taper the vehicles at the ends, which comprised the vestibule areas.  Initially, the routes on which mark 3 stock were limited but over the years clearances have been improved to allow them to operate over much of the system. The distance between the bogie centres and the ends means that relative movement between adjacent vehicles is more than with 20 metre stock, which imposes stresses on the coupling and gangways, especially on curves, and that in turn can affect ride quality and cause additional wear and tear. Ride quality was a particular problem with mark 4 stock initially.

Network Rail has decided to create a new Inter-City gauge to allow 26 metre long vehicles and this is where things get really interesting. The bogie spacing for the IEP vehicles, designed for this new gauge, has not yet been published. The normal bogie spacing on 26 metre vehicles is around 20 metres between centres (SNCF Corail stock above). But because the centre overthrow is proportional to the square of the distance between bogie centres, either the clearance works to accommodate the longer vehicles would be considerable, or the vehicles would have to be narrower, or the bogie centres will have to be closer together. The IEP width is given as 2.75 ie wider than mark 3. There is some scope for reducing tolerances by controlling the infrastructure more tightly, which will help somewhat. However, it has been suggested that the bogie spacing on the IEP could be between 17 and 18 metres. The lower figure would reduce overthrow but at the cost of an increased distance between the bogie centre and the ends of the vehicles. A 17 metre spacing would give 4.5 metres overhang at each end.

The question that then arises is what the effect of this will be on the inter-action between adjacent vehicles and what will that do for their dynamics? That this is a potential issue is known from experience with mark 4 stock when it is first introduced. What with this and bi-mode, a long period of teething troubles should come as no surprise. The worst case scenario cannot be ruled out: the fiasco of the Danish IC4 trains which have never operated as intended.

Bi-mode argument rumbles on

The bi-mode debate rumbles on. For decades the economics of diesel versus electric was argued

1. The overall thermal efficiency of diesel was around 30% (depending whom you asked) whereas electric was around 20%.
2. Electric trains and locomotives were less expensive in first cost than their diesel counterparts.
3. Electric trains and locomotives were less expensive in running cost than their diesel counterparts.
4. Electrification was not worth while unless traffic density was at a level sufficient to justify the installation of the fixed equipment.
5. Electrification caused less pollution at the point of use.
6. Electrification gave flexibility as to energy sources.

This probably lists all the most important factors. Applying figures to them is uncertain, but however it is done, the end result is a "triage". There are routes which must be electrified, routes which are definitely not worth electrifying, and routes where it makes little difference either way.

The other consideration is the break-even point for haulage by diesel locomotives rather than DMU, which most authorities suggest is five or six vehicles, and the end result is that the system will have routes which are not electrified throughout their length and are unlikely ever to be eg London to Cornwall. On such routes, until someone thought up the idea of bi-mode, it was accepted that diesel running under the wires was inevitable. I suspect the energy costs of carrying around diesel engines under the wires, and transformer packs off the electrified routes, is not particularly significant in the overall costs. And until recently, it was always argued that running a diesel powered train results in a saving of energy compared to running it under electric power!

The biggest costs on the railway are track costs, partly related to weight, the capital costs of the rolling stock, and staff costs, incurred in operating and maintaining trains. Energy costs are a relatively small item compared to the others.

From this, the following strategy emerges

• keep old rolling stock in operation for as long as possible and do not withdraw it unless maintenance costs are starting to climb or it fails to satisfy requirements.
• KISS - avoid complexity unless it is robust and the technology is mature so as to minimise the capital cost of new rolling stock and its subsequent maintenance costs.

On that basis, bi-mode has only a marginal place on the railway. As a mainstream operating practice it is nothing more than a fad, just the kind of fad that is to be expected from theoretically-minded civil servants. It is, incidentally, far from new, having been embodied long ago in the class 73 electro-diesels, a useful fleet which could operate under limited power away from electrified routes.

Fares rise row

The inflation-busting fares increase has led to a wave of indignation. Privatisation the railways has of course left several trainloads of hangers-on to support, but there are two factors that do not get a mention.

One is the rising cost of rolling stock. The real cost of a railway carriage is about 8 times what it was in the late 1950s, up from around £6000 now to over a million now, whilst the cost of a locomotive is up from around £30,000 then to nearly £3 million today. Allow a generous factor of 50 for inflation and it is still a huge increase. The new Hitachi trains will cost £2.6 million per carriage and there is also going to be a bill for infrastructure changes as someone thought it would be a good idea to make the carriages 3 metres longer, so they do not quite fit the present system.

The problem is compounded by the fact that most of the fleet is relatively new, all of the stock built before 1975 having been scrapped since privatisation. The public, and ill-informed press commentators and politicians are largely responsible, as this was a panic response to safety concerns. The predictable result of going beyond reasonability on safety has been to drive people to the less safe mode.

The other issue is the cost of speed. In 1963 trains were typically running at average speeds of 50 mph and top speeds of around 75 mph. Trains now are typically cruising at 125 mph. Costs are roughly proportional to the square of the speed. This has a knock-on effect on freight which also has to run faster to keep out of the way of the passenger trains. In 1963, freight trains typically ran at around 25-35 mph and the technique was to keep them rolling, which uses little energy at that speed.