david.hill64

Very strange. Most - probably all - of the Safety Plans that I have reviewed in recent years use the standard ALARP triangle. The peak region contains risks that are identified as intolerable and must be eliminated/mitigated. The base of the triangle contains those risks that are deemed acceptable without further review (and there are a lot of these) while the majority of risks fall into the tolerable region. Those risks in the tolerable region are subject to continuing reviews to ensure that the risk is As Low As Reasonably Practicable. (Some Safety Plans also allow for unacceptable risks. These are risks that are usually time bound and where elimination measures are not reasonable practicable. They are permitted if management accepts them. Happens sometimes during system migration). Risk is probability times consequence. An example of an acceptable risk: there is a possibility that a jumbo jet could crash onto a station building causing multiple casualties. This is an example of a high consequence but extremely low frequency event where the costs of mitigation (eg rebuilding the station underground) are grossly disproportionate to the benefit. Management would not be criticised for not having this under review. There will be many other risks that are deemed to be acceptable. Risks associated with signalling equipment assessed to be SIL4 are likely to be considered to be acceptable even though SIL4 does not guarantee absolute safety, for the very simple reason that absolute safety does not exist.

I think that the 350 figure was the total deaths attributed to falling from a train in the time that BR had been in existence. So less than 10 a year. As far as I know it excluded deaths and injuries at stations caused by people being hit by opening doors or injuring whilst alighting before the train had stopped. However, there were indications that the problem was getting worse. Fitting CDL on main line stock was a no brainer - it clearly fell within the realms of reasonable practicality.

Equipment always conforms to the standards in force at the time of design. Occasionally standards may change during the design process, in which case it is usual to allow the standards existing at the time of contract signature to prevail. Conformance with standards is checked by the relevant assessment body (NOBO, DEBO). The relevant body depends whether the applicable standards are TSI's and associated EN norms, or National Notified Technical Rules (where TSI's are not applicable). Sometimes where a new standard results in significant additional work to demonstrate compliance there may be a period of grace to allow compliance. An example is EN50128 where the 2011 revision caused significant problems for the signalling system manufacturers. Compliance to the 2001 version was allowed for many years after. Occasionally a new regulation may be introduced which applies retrospectively. Central Door Locking on slam door stock is a good example. This only happens when it is assessed that continuing use of the existing equipment presents a significant safety risk that can be mitigated by measures which are assessed as reasonably practicable (ie the cost of implementation is not disproportionate to the benefit). Otherwise there is no requirement for equipment to be upgraded as new standards are introduced. If there were, you would for example have to resignal the entire system to use ETCS* HSTs do not comply with current crashworthiness standards, but as demonstrated by most incidents have reasonably good protection. The driver of the HST which hit the tree was reported as being unharmed. The 60 year old design stood up well. *Assuming that the UK hasn't yet repealed this part of the EU legislation that requires all new works and resignalling to be done using this system.

I remember reading about drivers' recollections of A4's in reports of the 'Great Gathering' at York. More than one claimed that they had achieved 130mph+. Nothing verified of course. In the great scheme of things it is not particularly important whether Mallard's record could be broken. Somebody could design and build a steam loco that could achieve faster speeds, but what's the point? The British, German and American locos were of their age and that age has passed. Nobody is going to be designing new build steam for commercial use.

You need to remember that this is for events that affect individuals. For multiple fatality events a different figure applies. (Sorry, no idea what it is currently). Countries that don't use ALARP use different criteria for single and multiple fatality events.

Just to add to Northmoor's excellent comment on Platform Edge Doors. I was involved with the changes required to the signalling system on Bangkok Skytrain that were necessary when PEDs were installed. The installation works require changes to the high integrity (SIL4) software. These changes have to be independently assessed. It doesn't come cheap. The added checks also take processing time. We lost up to 2 seconds at each station stop while the additional processing takes place. Over the whole route this adds up. On a metro it can become critical. On BTS the main driver for the installation was the additional revenue from the electronic advertising. On Hong Kong MTR the main driver for the installation of full height Passenger Screen Doors was the energy saving made by not having the station air conditioning systems try to cool the tunnels. It is probably impossible to make a business case to retrofit PED/PSD on safety grounds alone, but as part of new build will be much easier to justify.

My early career was with British Rail Research. In the more junior grades promotion was linked with technical knowledge: up to a certain level (equivalent to BR management grades 3 or 4) the higher the grade, the better you knew your subject. When I became a section leader I was in charge of people who knew a lot more about their specialist subjects than I could ever hope to know. I remember being asked by my manager about how I was coping with managing the team. I pointed out that it was the first time I had ever been in the position of having less knowledge than the people I managed. It was clear to me from then on that the best way to manage was to know who you could rely on and then rely on them. Know too those who might have their own agenda and work with those as best you can. Try to pick up the basics of each subject within the team and know what you can answer and what needs support. I am sure that the best managers that I worked for operated that way. You don't need to be a technical expert in rail to manage rail, but you do need to have sufficient engineering/operations knowledge to be able to interact to get the best from your team. I think that the rail industry, like every other, follows diversity principles which often seem to ensure that the correct boxes are ticked rather than appoint on merit alone.

Not sure about the big railway as my recent experience is with metros and Taiwan HSR. These have diverse redundant comms routes with the option for local control if, for example, the route is completely severed in the middle.

I was in the cab of an HST leaving Reading towards the west when our green signal momentarily went to red before returning to the green. The drivers blamed the 37 in the triangle causing loss of detection on a set of points. They weren't at all fazed by it. However, for me, seeing a loco on an apparent conflicting route cause the events was an exercise in sphincter control. As Simon says, lots of things can cause a signal to revert to red. Getting a transient wrong side failure would be a different animal.

TI21 track circuits are supposedly traction immune, hence the name. They are still being installed today. The study talks about track circuits on AC electrified lines, which might mean they are simple DC type. Having written and/or approved signalling system safety cases, including for systems using TI21 track circuits, I find it very difficult to believe that wrong side failures would be more common than right side failures. I would also point out that the study predicts wrong side failures every 10-20 years. Given the length of time that DC and TI21 track circuits have been in use, you might have expected there to have been a few wrong side failures by now. It reminds me of the early days of safety cases, when we had an argument that the winter sun shining through a fence would cause shadows on the conductor rail resulting in partial melting of the ice on the conductor rail which would induce cyclic arcing of the collector shoes which would be at a frequency that would cause the AC track circuits to malfunction. I have a feeling that if the solar storm were large enough to cause this sort of issue, we might all have been fried anyway.

I thought it was too clean for one of theirs...............

TPWS was nearly Enhanced Automatic Warning System until someone pointed out that we might be accused of making an ass of ourselves.

True, but not in this case. The material is ductile and tough. It can support a heavily cracked structure before collapse. When I started work at BR Research - many eons ago it seems - my first project was trying to understand rolling contact fatigue. I tested a variety of different rail steels. The manganese steel was significantly different in its response to the tests. When you examined the structure after failure there was always a vast network of cracking before collapse. Completely different to the standard high carbon rail steels which gave way not long after the first crack propagated.

Interesting stuff manganese steel. The more you stress it, the harder it gets. It's used for prison bars.

No, modernisation meaning being able to train staff to be multi-disciplinary, being able to roster the correct number of staff to do a job, staff being able to share transport to worksites and staff being able to use modern technology to aid their work. Yes, it is likely to mean that fewer staff would be required to do a better job.

I would say that the bigger problem is the collapse of the sleeper underneath. After all, trains safely cross at speed gaps in rails every time they pass through pointwork. Provided that it is a single vertical crack and the rails are supported each side it will not present a derailment risk. Still needs clamping and replacing though. I suspect that this is being made public to help RMT fight modernisation of maintenance practices.

Roger Ford has just published his monthly newsletter. His analysis of likely London-Manchester journey times shows a likely saving of 10 minutes by using HS2. DfT think 30 minutes. Who will be correct?

Taking money from the capital expenditure (investment) budget to spend on maintenance is a sure sign of a failing company. The same applies at a national level.

Agreed, Derby was also a small part of the Bombardier Empire. When I worked for Bombardier (2013 - 2019) there was an internal notice about the company registration moving to UK. While the operational HQ was in Berlin, for tax purposes Bombardier Transportation became a UK company and paid its corporation taxes in UK.

But it's not 'Derby' in isolation. The works at Derby is a small part of the Alstom empire and history tells us that the French have form when it comes to merging/acquiring UK engineering companies and shipping the work to France. Think GEC and Chrysler for example. The chance of Alstom diverting work from France to UK is zero. Bombardier was a Canadian company but it's worldwide headquarters was a brass plaque in the City of London so at least there was an argument that it might have supported UK jobs because of that. No chance with Alstom. But even Bombardier did rationalize the business in a vain attempt to stay afloat. I think from Derby's perspective it is a pity that the Bombardier-Siemens merger (takeover by Siemens didn't happen). There is then a chance that the TfL order might have gone to Derby even if the design would have been done in Germany. But all of this ignores the fact that against the Chinese and the Koreans, western and Japanese companies are hopelessly uneconomic. If there is a large build of DMU's to replace the 15X fleet it will likely be CRCC that produces them. (At which point operators will long for the build quality of the CAF fleet).

Agreed. Even when UK was in the EU, how many rolling stock orders were made in UK for EU customers? Issues with gauging are far more important. At least Alstom has been trying to help by giving work such as Cairo monorail cars to Derby, but in the absence of domestic orders, things look grim. Remember too that Hitachi, Siemens and CAF have opened assembly plants in UK, so the Derby works has new competition. We have of course been here before: I remember when Litchurch Lane was producing modular bathrooms for buildings in an attempt to keep staff on the books.

Fatigue cracking and stress corrosion cracking are not the same thing at all.

Don't forget that the corrosion problem with IET is nothing like the traditional corrosion problem with steel bodies stock. It is stress corrosion cracking, previously unknown in the rail environment and not covered by any standard. Having said all of that, as a passenger I do not like the IET for the same reasons as noted above.

Yes, but you don't expect reputable Japanese companies to falsify QA documentation. I have a lot of sympathy with Hitachi.

Actually the people making the decisions are protected under English law if they don't upgrade to safer options provided that the safer options are not reasonably practicable (ie cost too much). They would be remiss if they hadn't considered the safer option, but do not need to adopt it. People may well remember the clamour post Ladbroke Grove for widespread adoption of ATP rather than TPWS. The enquiry agreed that TPWS was a reasonably practicable option whilst ATP, as an overlay to the existing signalling system, was not. Since then there has not been a single fatality on UK rail that could have been prevented if ATP were in place. So, pending installation of ETCS, we may very well conclude that not upgrading to the safer option - which would have taken money from the system that has been better used on other safety measures - was the correct decision. HST's were/are a fabulous train, but their time has come.