Just come up on the BBC News site https://www.bbc.co.uk/news/uk-57036247
Services on two of the country's busiest railways are facing severe disruption after cracks were spotted on the suspension units of some high-speed trains.
That's a real bummer! I hope than get this figured oey cut and back into running shape soon! This bit caught my eye as curious though: "Most Great Western Main Line trains to and from London Paddington have been cancelled, while London North Eastern Railways is asking passengers not to travel on the East Coast Main Line."Ummmm, if they don't want anyone to travel on the East Coast Main Line, why don't they just shut it down? I must be missing something....
LNER is a publicly owned company so need to continue to offer a public service where possible. Apparently trains are beginning to run again as units are inspected and cleared for service.
There was a piece about this in the Railway Magazine that I read earlier this week, interesting that it's suddenly become a much bugger problem. There's also a similar issue with CAF built stock, one of the other major builders of new UK trains.
GWR have found cracks on multiple Trains, that doesn't sound very good to be honest.
Apparently on the 800s, it's a bolster across the underframe that yaw dampers, anti-roll bars and jacking points are attached to where the cracking is occurring, the CF195s also have cracking issues where the yaw damper brackets are bolted directly to the underframe.
While the cracks may be small, rectification is going to be a headache. Roger Ford of Modern Railways mentioned that welding aluminium is a very challenging task compared to steel and yet that can only happen after all the electronics are isolated from the risk of stray currents. Striking an arc where they are not isolated and it is sayonara for the whole electronic outfit. There may well be grinding out to accomplish too.
It is only my personal opinion, but it feels like both CAF and Hitachi need to check their design software to verify that the modelling accurately reflects the real world hog/sag stresses/vibration stresses. It may be the mounts as produced in response to the present modelling are not robust enough in service. i think that the latest issue of RAIL magazine mentioned that, or that might be RAILWAY magazine. I will have to look at them both again. A more worrying alternative would be that the inspections reveal that materials are not to specification. I do hope that is not the case.
Another complication would be if the repairs have to be conducted at Newton Aycliffe (Hitachi) or Newport, Wales (CAF). The capacity to repair/modify a large number of vehicles might be a real strain on facilities and staff resources. Both Transpennine and Caledonian Sleeper are now involved as they run CAF multiple units and Mk5 coaches.
It's already known that the modelling was possibly insufficient in other areas. If you're interested in this sort of thing I recommend reading the RAIB report into the Class 800 that derailed after crashing into the back of an HST set, they suggest that part of the reason so may bogies came off is that the low speed collision dynamics were not fully modelled and understood during the design phase. They point out that this is not only the fault of Hitachi but also because the standards they need to comply with may not be wide ranging enough.
You're so right there borderriever. Welding aluminium to aluminium is tricky enough using TIG, Tungsten Inert Gas, the weld site has to be prepared to scrupulously clean standards before welding can take place, not to mention the high voltage and frequencies used which could destroy any adjacent sensitive electronics. I don't know the particular circumstances of the re welds in this case but if the two materials being joined are dissimilar metals e.g. ally to steel, then a transition type weld will be involved and that's a really difficult weld to achieve, a highly skilled job.
When I was a commissioning engineer in the Barrow shipyards I had to do a familiarization course on nuclear welding, we were given various simple test jobs to do including TIG welding, it was an eye opener, I have a great respect for these highly qualified welders that can do this type of work.
It is twenty-two years since I was in Barrow docks and fifteen since I was "volunteered" by my then shipmanager to take him from Newcastle Airport to Fishers offices at the port regarding a potential ship purchase. Waiting at the lock gates for them to open as the tide rose, going alongside to demobilse gear and people, loading up on equipment and people to depart right before the lock gates had to close on the ebb. To misuse the line from Aliens "people we are leaving!". It is where I boarded what I did not know at the time was to become my first command.