Bristol to Bath Spa - closed due to signalling problems

[whole diary]

[broadgage]

A generator seems a wise precaution, or possibly a battery bank if the load is small enough.

Generators do not have to be unreliable. It is infrequent use that tends to reduce reliability.
Weekly testing is advisable, preferably on load, this can be automated in order to reduce the labour requirement. If the generator fails to start for the weekly test then the cause can be investigated and rectified hopefully before the generator is needed in anger.
With a mains supply available normally, it is a simple matter to keep the engine warm and the starter batteries fully charged.

A single generator if of ample size could also supply the nearest station, and possibly other railway equipment.

[ellendune]

A generator seems a wise precaution, or possibly a battery bank if the load is small enough.

Generators do not have to be unreliable. It is infrequent use that tends to reduce reliability.
Weekly testing is advisable, preferably on load, this can be automated in order to reduce the labour requirement. If the generator fails to start for the weekly test then the cause can be investigated and rectified hopefully before the generator is needed in anger.
With a mains supply available normally, it is a simple matter to keep the engine warm and the starter batteries fully charged.

A single generator if of ample size could also supply the nearest station, and possibly other railway equipment.

Even with a weekly test on load my experience is that they are still not that reliable. 

[froome]

Another thought, given it happened at around 9am I expect many people just gave up and didn't travel to the market.  It would probably have been much more difficult if the failure had occurred mid afternoon when Bath was full with people who then needed to return home.

The market did seem to me relatively quiet compared to what I expected (and on a sunny day as well).

[broadgage]

Generators are indeed not always reliable, even if tested weekly.
All too often the installation is done incorrectly and permits of a brief test but not a prolonged run on load.

I have considerable experience of standby generators and the testing thereof, and assisting in finding out what went wrong after a failure. IME^▸ (in my experience) the most common faults are, in approximate order of popularity as follows.

1)Defective or discharged starter batteries-------the remedy is obvious.
2)Low water in cooling system, overheat protection stops engine-----check regularly
3) Engine starts but fails to take over the load due to defective, or misunderstood, changeover switchgear.

4)Engine runs but stops for want of fuel before power is restored.
5)Engine runs but stops due to electrical overload/unauthorised extra loads.
6)Engine runs but stops due to low lubricant oil level.

Or finally, which is not truly a fault at all, it all works perfectly but the standby generator only supplies ESSIENTIAL loads as was the design brief. The elfansafety then send everyone home because they feel that the workplace is unsafe without every light and electric heater working.

The first 3 reasons given account for the great majority of failures IME. Learning points include use of good quality starter batteries, preferably of twice the recommended capacity. Duplicated battery chargers with alarm in case of failure. Replace starter batteries every 4 years.
Check coolant levels regularly, general maintenance to prevent leaks.
Test not just the engine but all related automatic or manual changeover switchgear.

[grahame]

There appears to be a lot of trains in the area cancelled due to traincrew shortages

Including 2M12, the 15:06 Westbury to Swindon. Interestingly, for the one day only an Empty Coaching Stock train called 5M12 ran from Westbury to Swindon scheduled at - err - 15:06.   

[stuving]

... Or finally, which is not truly a fault at all, it all works perfectly but the standby generator only supplies ESSIENTIAL loads as was the design brief. The elfansafety then send everyone home because they feel that the workplace is unsafe without every light and electric heater working.

That's the one I remember - having inherited the backup generator from the previous users of the factory, no-one had gone through the process of splitting the circuits between essential and the rest, and making sure the essential power demanded was available. So the generator struggled up to a lot less than 50 Hz, and overheated all the fluorescent ballasts, one of which (oil-filled) burst and produced an atomised spray of ... something. We hoped it was silicone - but there was a rumour it was a PCB.

NR^» (Network Rail - home page) don't have those all over the place - but they gave a 5-year contract to Aggreko in May 2016, for mobile generators to cover both planned and emergency needs. So why didn't they get one of those in?

“Safety and minimum disruption are paramount on the rail network and this new framework agreement will enable us to provide a fully coordinated service and to put in place further contingency plans to ensure power resilience. We have worked with Network Rail for many years to supply power to support planned and reactive maintenance, supporting construction projects, and emergency power outages. This long-term agreement gives Aggreko the opportunity to work closer with Network Rail to find new innovative solutions to meet its future needs."

Aggreko's specialist RISQS accredited UK^▸ (United Kingdom) rail division has served the sector for 10 years and operates from 18 locations throughout the UK and Ireland. The company has the largest fleet of generators in the UK and has developed innovative emergency generation technologies for the rail industry, such as a new 60kVA 650 volt two-phase mobile generator for signalling projects and infrastructure maintenance, and fuel-saving hybrid power solutions that minimise noise and emissions.

Well, it would depend on how much power that much signalling needs (though it was only a few miles). And, as reported, it wasn't the loss of power that mattered - that was restored within an hour. It was some consequential damage (which might be just one of those things, or might be one of those things that was NR's fault). I wonder whether the damage was to the switchgear where the external power feeds in - in which case connecting a generator might not be quick enough to help. More generally, the response time of a mobile generator might always be a few hours - more suitable for longer-term emergencies.

[SandTEngineer]

In response the earlier question as why no generators.  Standby generators are notoriously unreliable as they stand idle for almost all of the time.  That is why many users who need standby capacity use dual supply.

I have seen them at signalling centres, but I do not recall seeing them at remote locations. 

However I do not know what NR^» (Network Rail - home page)'s policy is on these. 

Well in my time in NR maintenance they were all tested 'on load' every 4 weeks and every time they were used 'in anger' they worked perfectly.  I can only recall having to bring in a mobile generator once and that was to cover the rebuild of the permanent one over an extended period.

[rower40]

At the risk of drifting well off-topic...
We had a UPS (uninterruptible power supply - just a load of batteries and stuff to turn it into 220V AC) to feed four servers, at least long enough to shut them down in an orderly fashion if we lost mains power.
One day, the supply to the buiding failed.  Our four servers kept going, and the display on the UPS said that it could keep them going for another hour or two.  So we decided to shut them down, as no-one could use their desktop PCs to acess them anyway.
But all the terminals (screens and keyboards for logging in to the servers) had no power! So we couldn't type in the shutdown commands.  And the UPS only had 4 power sockets.  So there was a frantic search for a laptop with a) terminal emulation software and b) enough battery power left to be able to power off one of the servers, so we could unplug that one from the UPS, and then plug in a terminal to shut down the other 3.

Moral: rehearse your emergency plans.

[stuving]

At the risk of drifting well off-topic...

Moral: rehearse your emergency plans.

Very true. And, of course, the same also applies to data recovery off backup.

[Chris from Nailsea]

Purely for the record - the story from the BBC^» (British Broadcasting Corporation - home page):

Rail passengers 'stranded' after power cut near Bristol


Hundreds of passengers queued for replacement buses at Bristol Temple Meads

Hundreds of rail passengers were "left stranded" after a power cut on a main line in the west of England.

GWR^▸ (Great Western Railway) said a power failure had caused a signalling systems failure between Bath Spa and Bristol Temple Meads stations.

It affected services between Swindon and Bristol Temple Meads and Westbury and Bristol Temple Meads.

A spokesman said the firm was "unable to source replacement road transport" and advised customers not to travel.



Several trains were cancelled, and one person reported on social media that "hundreds" of passengers had been "left stranded" in Bristol until Sunday.

Another passenger said they had been told by staff to go home because no replacement buses were available at Westbury.

Network Rail said engineers were working to repair damage to the railway's signalling system.

GWR said disruption was expected until the end of the day on Saturday.

[WelshBluebird]

"Several trains were cancelled, and one person reported on social media that "hundreds" of passengers had been "left stranded" in Bristol until Sunday."

Really? Funny how I fairly easily got a train from Bristol to Bath at around 8pm.
I am sure there would have been longer waits for some people (I was pretty lucky in that I managed to jump on a service that was 34 minutes late just before it actually left), but I seriously doubt people were "left stranded".

[Chris from Nailsea]

... but that story was on the BBC^» (British Broadcasting Corporation - home page)!  What could possibly be inaccurate about it?? 

[stuving]

... but that story was on the BBC^» (British Broadcasting Corporation - home page)!  What could possibly be inaccurate about it?? 

I guess the most likely inaccuracy would be that more than one person reported that on social media - if only by passing it on - is that what you meant?

[ChrisB]

Another thought, given it happened at around 9am I expect many people just gave up and didn't travel to the market.  It would probably have been much more difficult if the failure had occurred mid afternoon when Bath was full with people who then needed to return home.

That would have been considered by GWR^▸ (Great Western Railway). If it ws thought that the power outage was going to last all day at that stage (and it did), would you risk transporting many thousands to the Christmas market & not be able to get them back again easily, or would you not attempt to carry them in the first place & your lift easier?

I think they made the right decision. Those few *needing* to travel, I'm sure got away somehow.