British politicians are now saying that the future for the railways is hydrogen or battery power and that diesel traction should be phased out by 2040.
Batteries have made vast improvements over the past couple of decades. Lithium supply is a problem but several of the elements on the top left hand side of the Periodic Table are candidates and we can expect substitutes to be adopted. However, the underlying problem of energy density is unlikely to be solved since there is no Moore’s Law in operation. The likely use of battery power will be for use on routes which are electrified for most of their length; one could envisage a train running from Paddington to Maidenhead on electric power and continuing to Bourne End and Marlow under battery power, where it could receive a top-up before returning; similar trains could also provide the all-day shuttle service on the branch. Apart from the provision of batteries, they would be similar in almost all respects to the regular fleet of electric trains running only on electrified routes.
Hydrogen power dead end?
Hydrogen powered trains, on the other hand, look like a specialised niche. The hydrogen has to be made somehow, probably by electrolysis of water. This energy is recovered in a fuel cell where it is converted into electricity. Both processes result in losses, on top of the usual losses associated with the drive train and control systems. That is not the end of the energy losses. There are also losses associated with the transport of the hydrogen, which is not a portable fuel. Hydrogen will liquify only at extremely low temperatures, below 33°K. That is cold. At ambient temperatures is has to be compressed and put in tanks capable of withstanding extreme high pressures, which means they are heavy, and both compression and liquefaction consume large amounts of energy.
A German experiment aims to use otherwise unusable electricity from wind generation to produce the hydrogen but this seems an inefficient and expensive way of making use of it.
What is the overall thermal efficiency when all of this is taken into account? There is a discussion of the subject here, in relation to automotive applications of hydrogen fuel cells.
Then there is platinum to consider. Fuel cells require platinum catalysts. Alternatives are not even on the horizon. It is one of the rarest of elements. Platinum mines are not environmentally friendly. Taking one thing with another, this technology is nothing like as clean as it seems, and not particularly cost effective.
Battery power might have specialised applications such as the branch line off an electrified main line, referred to above. Hydrogen power looks like a dead end. Neither is a candidate for the hoped-for replacement of diesel power. Politicians should get to grips with basic chemistry and physics before going public about their aspirations.
tisdag 27 mars 2018
lördag 24 mars 2018
GWML electrification disgrace to British engineering
torsdag 16 november 2017
Super Express - how super?
The new Hitachi bi-mode trains are now coming into service; after the embarrassing maiden trip, it is possible to make a more balanced judgement. It will be a while before I get an opportunity to travel in them, but the verdict seems to be that the underfloor engines are not too bothersome and the main complaints are about the hardness of the seats. The air conditioning problem on the inaugural run was due to the failure of the pump which removes the condensed water, but one wonders why the system was designed to need one, when previous air conditioning systems relied on gravity to drain away the condensate. What became of the principle of keeping things simple?
Ian Walmsley, writing in Modern Railways, said that the Great Western ones so far running are all right as commuter trains, but not much better than that. The big question mark concerns performance. The engines were supposed to have been de-rated to improve reliability, but this will have a detrimental effect on timekeeping, especially now that so much of the electrification is uncompleted and likely to remain so for a long time to come. There are also unsolved issues such as the bridge over the main line at Steventon; until it is resolved, there will be a break in the electrification. Given the problems with changeover from diesel to electric on the first journey, having to carry out the operation is going to create a long-term risk to reliability. This saga is going to run for a few years yet.
In 1985 I was the co-author of an article that was published in the Railway Magazine, written slightly tongue-in-cheek, suggesting that the Great Western Main Line should be electrified on the third rail system. Perhaps the idea was not so daft.
Ian Walmsley, writing in Modern Railways, said that the Great Western ones so far running are all right as commuter trains, but not much better than that. The big question mark concerns performance. The engines were supposed to have been de-rated to improve reliability, but this will have a detrimental effect on timekeeping, especially now that so much of the electrification is uncompleted and likely to remain so for a long time to come. There are also unsolved issues such as the bridge over the main line at Steventon; until it is resolved, there will be a break in the electrification. Given the problems with changeover from diesel to electric on the first journey, having to carry out the operation is going to create a long-term risk to reliability. This saga is going to run for a few years yet.
In 1985 I was the co-author of an article that was published in the Railway Magazine, written slightly tongue-in-cheek, suggesting that the Great Western Main Line should be electrified on the third rail system. Perhaps the idea was not so daft.
Tunnel of steel not needed after all
It now turns out that the Great Western Main Line's "Tunnel of Steel" was not necessary after all. It seems, as Roger Ford explains in "Informed Sources", that there were design errors which went unnoticed.
There have indeed been problems with overhead electrification on the East Coast Main line, which was carried out to super-economical standards, but the West Coast route, electrified in the 1970s, has performed reliably even though it passes through some of the most exposed uplands in the country; in comparison, it looks like gossamer.
lördag 21 oktober 2017
IEP problems - give them a break
The very public failures of the Hitachi IEP on its first run in public service have been the subject of much criticism in the press. I am no fan of this project but the criticism is unfair at this stage. It takes at least a couple of years in public service to get a new design of train working reliably.
British Railways Mark 1 stock is often held up as an example of robust simplicity, but its introduction was plagued with problems. The ride quality of the trains deteriorated rapidly due to the design of the BR1 type double bolster bogie. This led to the setting up of a research programme which eventually resulted in the B4 bogie, but that took almost a decade. In the meantime, the Commonwealth bogie with cast steel frame was adopted as an interim replacement; the ride quality was much improved but it was a heavy piece of equipment.
Ride quality became even more of an issue when the mark 1 stock was adapted as an electric multiple unit design for service on the newly electrified Kent Coast lines in 1959. The standard BR bogie was modified due to the reduced clearances on the route. So bad was the ride quality that the trains became known as the "Rock and Roll Trains". The ride over the motor bogies was even worse.
That was not all. The double glazing seals did not work and the spaces between the panes filled up with water, so the inner panes were removed, with double glazing not being reinstated until the trains were given a mid-life refurbishment in 1981.
Mark 1 stock also suffered badly from corrosion from the inside out, especially around the windows. The window problem was eventually resolved by placing the windows in aluminium frames, but corrosion remains an issue for the preservation movement which relies on these vehicles.
Similar reliability issues affected the locomotives. The flagship express steam locomotive Duke of Gloucester was a notoriously poor performer and was quickly dispatched to the scrapyard. Years later, it was rescued and the original design team brought together with a view to discovering the cause of the problems. These turned out to be a combination of inaccurate construction and bad design decisions arising from office politics. Once most of the faults had been corrected, the performance of the machine was transformed, making it possibly the best of the British express designs. Before that there had been the issues with the Bulleid Pacfics, which were troublesome until they received their major rebuild in the mid-1950s, following a serious accident.
The issues continued with subsequent generations of stock. Rust affected the earlier Mark 2 stock and the suburban versions of Mark 3; the class 455 stock need a major repairs as the floors dissolved into flakes of rust. Air conditioning was unreliable until about ten years ago. Electrostars were another class which did not settle down for almost five years after they first came into service.
It is possible to build new trains which will run reliably, but they have to be technically conservative. The new locomotive hauled fleet for Northern should go into service without problems, since they will be pulled by locomotives which have been in use for several years and hauled carriages are a simpler affair altogether. But given the complexity of the IEP, and based on historical experience, it is too soon to start criticising. The design is indeed complicated, unnecessarily so, and costs about double what it ought to have done. But those decisions were made by the civil servants and the Department for Transport. Hitachi and its engineers should not be made to take the blame.
British Railways Mark 1 stock is often held up as an example of robust simplicity, but its introduction was plagued with problems. The ride quality of the trains deteriorated rapidly due to the design of the BR1 type double bolster bogie. This led to the setting up of a research programme which eventually resulted in the B4 bogie, but that took almost a decade. In the meantime, the Commonwealth bogie with cast steel frame was adopted as an interim replacement; the ride quality was much improved but it was a heavy piece of equipment.
Ride quality became even more of an issue when the mark 1 stock was adapted as an electric multiple unit design for service on the newly electrified Kent Coast lines in 1959. The standard BR bogie was modified due to the reduced clearances on the route. So bad was the ride quality that the trains became known as the "Rock and Roll Trains". The ride over the motor bogies was even worse.
That was not all. The double glazing seals did not work and the spaces between the panes filled up with water, so the inner panes were removed, with double glazing not being reinstated until the trains were given a mid-life refurbishment in 1981.
Mark 1 stock also suffered badly from corrosion from the inside out, especially around the windows. The window problem was eventually resolved by placing the windows in aluminium frames, but corrosion remains an issue for the preservation movement which relies on these vehicles.
Similar reliability issues affected the locomotives. The flagship express steam locomotive Duke of Gloucester was a notoriously poor performer and was quickly dispatched to the scrapyard. Years later, it was rescued and the original design team brought together with a view to discovering the cause of the problems. These turned out to be a combination of inaccurate construction and bad design decisions arising from office politics. Once most of the faults had been corrected, the performance of the machine was transformed, making it possibly the best of the British express designs. Before that there had been the issues with the Bulleid Pacfics, which were troublesome until they received their major rebuild in the mid-1950s, following a serious accident.
The issues continued with subsequent generations of stock. Rust affected the earlier Mark 2 stock and the suburban versions of Mark 3; the class 455 stock need a major repairs as the floors dissolved into flakes of rust. Air conditioning was unreliable until about ten years ago. Electrostars were another class which did not settle down for almost five years after they first came into service.
It is possible to build new trains which will run reliably, but they have to be technically conservative. The new locomotive hauled fleet for Northern should go into service without problems, since they will be pulled by locomotives which have been in use for several years and hauled carriages are a simpler affair altogether. But given the complexity of the IEP, and based on historical experience, it is too soon to start criticising. The design is indeed complicated, unnecessarily so, and costs about double what it ought to have done. But those decisions were made by the civil servants and the Department for Transport. Hitachi and its engineers should not be made to take the blame.
onsdag 11 oktober 2017
New Thameslink nasties
The new class 700 Siemens trains are even worse than the class 319 stock which it replaces.
- There is nowhere to put a cup of coffee apart from balanced on one's lap. Had the designers never heard of "food to go"? Do they even travel in trains?
- The uncomfortable seats have no spacers in between the pairs so if there is one large person in the window seat, his or her neighbour will be half-way off the seat by the gangway.
- The skirting level duct cuts into the space to put one's feet so that one is forced to sit twisted round.
- The lighting is dim - there is only a strip in the centre of the ceiling.
- What is the reason for the curved shape of the windows?
onsdag 16 augusti 2017
UK electrification schemes cancelled #2
The new GW electrification is noteworthy for the chunkiness of the overhead structures, which are heavier than the notably solid gantries installed for the 1500kV Great Eastern electrification which was installed in 1949. One of the reasons for the adoption of 25kV electrification was that the smaller current flows made it possible to use thinner and lighter contact wires, and consequently lighter and cheaper structures. The Great Western's tunnel of steel must come at a commensurately heavy price, which has helped to push further electrification schemes into the realm of the unaffordable.
The overhead structures for the 15kV system used in Switzerland, Germany and Sweden are like gossamer in comparison. What has happened to let loose this orgy of over engineering?
The overhead structures for the 15kV system used in Switzerland, Germany and Sweden are like gossamer in comparison. What has happened to let loose this orgy of over engineering?
Prenumerera på:
Inlägg (Atom)