31 Jan 2013

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.

26 Jan 2013

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

25 Jan 2013

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.

24 Jan 2013

26 metres is too long

Corail stock - markings 

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.

19 Jan 2013

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.

7 Jan 2013

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.