Tram Derailment at Bulwell 12/06/2023

[Purple Train]

It could well be a bush or a hanging branch yes. I might book into specsavers just in case though…

I've watched it again and I can definitely see something that looks like a person.
I haven't felt this confused since I was in the hall of mirrors.

I need to stress it is only a local rumour, but in the area it is suggested that a lightning strike damaging equipment during the heavy thunderstorms in the area at the time was a factor in the behaviour of the equipment.

Damaging the FPI, giving a false signal? Or damaging something related to the pointwork? Is there anything that could be damaged at that moment relating to the movement of those particular points? There doesn't seem to be a strike visible on the video, for instance, so it would have to be remote stuff, unless it was damaged earlier in such a way that caused the points to swing back and forth?

 

[mainframe444]

I've watched it again and I can definitely see something that looks like a person.
I haven't felt this confused since I was in the hall of mirrors.

Damaging the FPI, giving a false signal? Or damaging something related to the pointwork? Is there anything that could be damaged at that moment relating to the movement of those particular points? There doesn't seem to be a strike visible on the video, for instance, so it would have to be remote stuff, unless it was damaged earlier in such a way that caused the points to swing back and forth?

Lots of speculation on here.

I worked on this tramway for many years, and the way these points work has not changed.

These are spring points.

They have no motor.

The blades cannot move unless a tram passes over them northbound which pushes the blades across and then they spring back.

They always lay points left when approached from Hucknall so the tram goes into the southbound platform.

The FPI has two states when powered , if the points have swung back correctly it will show points left, if not it will show a horizontal bar.

This is acted on the same as a stop signal, the driver should stop, get out, work the points with a points bar and attempt to get points left.

If not, they contact control.

There is no need for facing point locks, the FPI is always visible from a suitable distance for the driver to see it and act accordingly.

There are I think three possibilities….

1) The driver has failed to notice the FPI on a bar and passed over points which have not swung back. As the front bogie passes over this has caused them to go back to the correct points left status, causing the centre bogie to take the left route and derail as the tram tries to follow the front bogie.

2) A “Swiss Cheese” moment, the points have not gone back following a northbound tram, a lightning strike on the point controller causing the FPI to go out, and the driver not following their training which is to treat a blank signal or FPI as a stop signal and act accordingly

3) A wrong side failure, despite the points not having swung back they have been detected as correctly set, so the driver has rightly assumed the tram will take the correct route.

The RAIB report will I’m sure reveal what happened.

FPI = FACING POINT INDICATOR.

Shows the driver how a set of points they are approaching on a diverging route are set ahead of them.


Hope this clarifies things!

 

[Purple Train]

Looking at the film again, the shape that I think could be a person seemed (possibly) to have clothing that matched the pattern of hi-vis... someone trying to fix a technical failure perhaps?

Lots of speculation on here.

I worked on this tramway for many years, and the way these points work has not changed.

These are spring points.

They have no motor.

The blades cannot move unless a tram passes over them northbound which pushes the blades across and then they spring back.

They always lay points left when approached from Hucknall so the tram goes into the southbound platform.

The FPI has two states when powered , if the points have swung back correctly it will show points left, if not it will show a horizontal bar.

This is acted on the same as a stop signal, the driver should stop, get out, work the points with a points bar and attempt to get points left.

If not, they contact control.

There is no need for facing point locks, the FPI is always visible from a suitable distance for the driver to see it and act accordingly.

There are I think three possibilities….

1) The driver has failed to notice the FPI on a bar and passed over points which have not swung back. As the front bogie passes over this has caused them to go back to the correct points left status, causing the centre bogie to take the left route and derail as tries to follow the front bogie.

2) A “Swiss Cheese” moment, the points have not gone back following a northbound tram, a lightning strike on the point controller causing the FPI to go out, and the driver not following their training which is to treat a blank signal or FPI as a stop signal and act accordingly

3) A wrong side failure, despite the points not having swung back they have been detected as correctly set, so the driver has rightly assumed the tram will take the correct route.

The RAIB report will I’m sure reveal what happened.

FPI = FACING POINT INDICATOR.

Shows the driver how a set of points they are approaching on a diverging route are set ahead of them.


Hope this clarifies things!

Very interesting, thank you - out of interest, how could the switch blades move, as seems to be the case in the film? Or is it an optical illusion? Both switch blades seem to move, even when not in the glare of the headlights.

 

[edwin_m]

Looking at the film again, the shape that I think could be a person seemed (possibly) to have clothing that matched the pattern of hi-vis... someone trying to fix a technical failure perhaps?

Very interesting, thank you - out of interest, how could the switch blades move, as seems to be the case in the film? Or is it an optical illusion? Both switch blades seem to move, even when not in the glare of the headlights.

It seems highly unlikely that they would move spontaneously against the spring, and this would have to be after the tram had passes the indicator. Without any detailed knowledge of the mechanism I guess the springing would have to have failed, after which they might conceivably move due to vibration from the approaching tram or some other source.

 

[mr_moo]

The more I re-watch that video the more I'm convinced it's a person on the side of the track. They seem to move just as the tram passes and thus potentially they could be pulling a wire or rope etc that they had attached to the switch blades. Maybe I'm hallucinating etc but for point blades to move like that against the direction of the spring needs some kind of decent force, unless indeed the spring had come off (or been removed) and the blades moved under vibration (or other force).

 

[Purple Train]

The more I re-watch that video the more I'm convinced it's a person on the side of the track. They seem to move just as the tram passes and thus potentially they could be pulling a wire or rope etc that they had attached to the switch blades. Maybe I'm hallucinating etc but for point blades to move like that against the direction of the spring needs some kind of decent force, unless indeed the spring had come off (or been removed) and the blades moved under vibration (or other force).

They would need some knowledge of how the points operate to successfully commit such an act.

 

[m79900]

They would need some knowledge of how the points operate to successfully commit such an act.

Very superstitious, but perhaps, if someone did it intentionally, could it be related to the stabbings the day after?

 

[ChrisC]

There’s still no trams running on the section of line between Highbury Vale, Bulwell and Hucknall. Also there are no replacement buses available. EMR are accepting tram tickets between Hucknall and Nottingham, but there is only 1tph for most of the day Mon-Fri, as EMR have never restored the pre covid 2tph service through Hucknall. I presume that TrentBarton are currently getting some extra passengers on the Threes route. The Stagecoach 141 bus also does seem to be picking up a few extra passengers when it actually manages to run on time.

 

[Purple Train]

There’s still no trams running on the section of line between Highbury Vale, Hucknall and Bulwell. Also there are no replacement buses available. EMR are accepting tram tickets between Hucknall and Nottingham, but there is only 1tph for most of the day Mon-Fri, as EMR have never restored the pre covid 2tph service through Hucknall. I presume that TrentBarton are currently getting some extra passengers on the Threes route. The Stagecoach 141 bus also does seem to be picking up a few extra passengers when it actually manages to run on time.

Useful data, thank you. I'm travelling up to the area in a couple of days, and was planning on taking a tram trip for old times' sake, so I presume that's off the table. I will report my findings!

In the ten years I lived in the area, I don't think I ever saw a 141 on time!

 

[duffield]

Useful data, thank you. I'm travelling up to the area in a couple of days, and was planning on taking a tram trip for old times' sake, so I presume that's off the table. I will report my findings!

In the ten years I lived in the area, I don't think I ever saw a 141 on time!

Quote from NET re Bulwell repairs (via the BBC today):
"Although this work is expected to take until the end of the week to complete, NET will make every effort to restore services as soon as it can."

If it's not done when you visit, you can still travel on the rest of the network, e.g. to any of the other three terminal stops at Phoenix Park, Clifton South or Toton, these routes were running normally when I used the tram today.

Edit: The BBC TV local news just reported more specifically that they hope to have the service running "by Friday".

 

[Purple Train]

Quote from NET re Bulwell repairs (via the BBC today):
"Although this work is expected to take until the end of the week to complete, NET will make every effort to restore services as soon as it can."

If it's not done when you visit, you can still travel on the rest of the network, e.g. to any of the other three terminal stops at Phoenix Park, Clifton South or Toton, these routes were running normally when I used the tram today.

Edit: The BBC TV local news just reported more specifically that they hope to have the service running "by Friday".

Thank you

 

[duffield]

Trams now reported to be running normally on all routes after repairs completed.

 

[mr_moo]

Very superstitious, but perhaps, if someone did it intentionally, could it be related to the stabbings the day after?

Hadn't noticed that date coincidence. Probably not, but an interesting point.

They would need some knowledge of how the points operate to successfully commit such an act.

To be fair, spring loaded points are pretty simple things and an observer wanting to do some damage wouldn't need too much time to work out how to do this.

 

[Purple Train]

Trams now reported to be running normally on all routes after repairs completed.

Good. When I passed yesterday there were no signs of closure except a large construction vehicle on the tramway at Bulwell.

 

[Jozhua]

Worth noting that the 'swiss cheese' approach was still successful in preventing serious injury due to the low speed approach to the points.

I do worry that if it had occured in the morning rush things would be different, but thankfully that did not occur.

 

[nowicki2]

The raib have started an investigation and have posted briefly about it on there website

 

[Mojo]

Link to RAIB report https://www.gov.uk/government/news/report-022024-derailment-of-a-tram-at-bulwell

At around 17:06 hrs on 12 June 2023, a southbound tram, travelling at around 41 km/h (25 mph), approached a set of facing points in an unsafe condition at the north end of Bulwell tram stop in Nottingham. As it travelled over the points, the first and second bogies of the tram were routed in different directions and the tram subsequently derailed.

During the derailment, the tram struck a pole that supported overhead line equipment causing a pane of glass to dislodge and strike a passenger, resulting in minor injuries. The driver of the tram also suffered a minor injury. Significant damage was caused to the tram and infrastructure, with the line reopening on 23 June following extensive repairs.

The set of spring-loaded points were in an unsafe position because they had not reset correctly after the passage of the previous two northbound trams. This can sometimes happen in normal working conditions, but the risk of this happening at the time of the accident had possibly been increased due to the environmental conditions causing the slide plates to be dry or contaminated.

A visual indicator located alongside the points, which was showing that the points were not in the correct position, was not observed by the tram’s driver. The driver believed that they would be informed if there were any issues with a set of points but had not been so on this occasion. The driver had probably become conditioned to there being no issues at this location and was also possibly distracted.

RAIB’s investigation found that Nottingham Trams Limited did not have an effective policy in place to inform drivers of points failures and had not specifically assessed the risk of a driver incorrectly passing a lineside indicator. RAIB also observed that the process Nottingham Trams Limited used when introducing a new system to the tram fleet had not considered the effect the change may have on its tram drivers.

 

[Lockwood]

Something I have a curious interest in at work (as opposed to a Work Interest) is human factors and interactions.

The tram involved had been recently fitted with a new vigilance system
(paragraph 12). The driver stated that this required slight alterations to the way
they operated the tram, compared to other vehicles in the fleet. The possible
additional cognitive load needed to adapt to this different style of operation may
also have been an additional distraction to the driver.

That stood out a little bit - a system that is implemented to increase safety and ensure vigilance may have contributed and reduced the driver's vigilance.

An interesting example of the Law of Unintended Consequences, and how process changes that are there for a nett gain can have negative impacts as well.

 

[507 001]

Something I have a curious interest in at work (as opposed to a Work Interest) is human factors and interactions.

The tram involved had been recently fitted with a new vigilance system
(paragraph 12). The driver stated that this required slight alterations to the way
they operated the tram, compared to other vehicles in the fleet. The possible
additional cognitive load needed to adapt to this different style of operation may
also have been an additional distraction to the driver.

That stood out a little bit - a system that is implemented to increase safety and ensure vigilance may have contributed and reduced the driver's vigilance.

An interesting example of the Law of Unintended Consequences, and how process changes that are there for a nett gain can have negative impacts as well.

This is a concern I have too. We’re having vigilance fitted to the M5000s in the next few months too.

Tram driving is such an intensive task anyway in terms of concentration that I suspect (and as well as this report, some anecdotal evidence I’ve seen from Nottingham suggests I’m right) that it’ll actually prove to be more of a distraction. It is a decision that has been made by people who don’t drive unfortunately.

 

[martin2345uk]

This is a concern I have too. We’re having vigilance fitted to the M5000s in the next few months too.

Tram driving is such an intensive task anyway in terms of concentration that I suspect (and as well as this report, some anecdotal evidence I’ve seen from Nottingham suggests I’m right) that it’ll actually prove to be more of a distraction. It is a decision that has been made by people who don’t drive unfortunately.

I take it trams have a DSD/dead mans handle somehow? Will they adapt that to create a vigilance device or will it be a separate thing?

 

[Nym]

The Vigilance for TfGM is a separate device to the Deadman’s. Being fitted at the same time as the Tram Overspeed Protection System (Yes, TOPS!).

 

[507 001]

I take it trams have a DSD/dead mans handle somehow? Will they adapt that to create a vigilance device or will it be a separate thing?

Yes, on an M5000 the DSD is part of the TBC (traction/brake controller). It’s quite an old fashioned one (and as discovered at Sandilands, quite an ineffective one) as it requires the TBC to be pushed down at all times.

DVD, when fitted, will require the TBC to be moved periodically, if it isn’t an alarm will sound and the driver will have to press a big yellow button to reset it.

 

[martin2345uk]

Yeah our trains have a DSD built into the power controller but it’s not comfortable to keep it held down so everyone uses the pedal instead, are the M5000 ones quite easy to push down at least?

 

[507 001]

Yeah our trains have a DSD built into the power controller but it’s not comfortable to keep it held down so everyone uses the pedal instead, are the M5000 ones quite easy to push down at least?

By design they’re not too bad to hold down, some of them are very heavy though which can get very tiring, very quickly.

I’d much prefer a pedal, but it is what it is, another feature of the M5000s that’s far from ideal.