There is yet another case of an HGV that has got stuck with a level
crossing barrier coming down between the cab and the body.

<https://www.thescarboroughnews.co.uk/news/transport/lucky-escape-for-huge-lorry-stuck-in-level-crossing-barrier-near-bridlington-4542535>

Leaving aside that this shouldn't be possible if the driver has obeyed
the yellow and red lights of the wig-wag, what is the general advice to
drivers if *somehow* they end up in that situation?

This is a special case that the angle of the track to the road means
that the lorry stopped well short of the track, but supposing it had
stopped with its nose fouling the track?

Is a level crossing barrier designed to be weak enough that an HGV can
snap it off if it needs to reverse (or drive forward) to move clear of
the track? Obviously there is then an insurance claim to be settled, but
that is trivial compared with the risk of a collision.

Seems that in this case they were able to get NR staff to control the
barrier manually to raise it, and get things sorted within an incredible
short time of 25 minutes. I imagine NR staff must have been working
at/near the crossing at the time. I believe that crossing is a
recognised place for road/rail vehicles to transition between road and rail.

On 04/03/2024 20:25, NY wrote:
> Is a level crossing barrier designed to be weak enough that an HGV can
> snap it off if it needs to reverse (or drive forward) to move clear of
> the track? Obviously there is then an insurance claim to be settled, but
> that is trivial compared with the risk of a collision.
>
>

I would have thought a HGV would be easily able to snap the barrier.

On 04.03.2024 21:25, NY wrote:
> There is yet another case of an HGV that has got stuck with a level
> crossing barrier coming down between the cab and the body.
>
> <https://www.thescarboroughnews.co.uk/news/transport/lucky-escape-for-huge-lorry-stuck-in-level-crossing-barrier-near-bridlington-4542535>
>
> Leaving aside that this shouldn't be possible if the driver has obeyed
> the yellow and red lights of the wig-wag, what is the general advice to
> drivers if *somehow* they end up in that situation?
>
> This is a special case that the angle of the track to the road means
> that the lorry stopped well short of the track, but supposing it had
> stopped with its nose fouling the track?
>
> Is a level crossing barrier designed to be weak enough that an HGV can
> snap it off if it needs to reverse (or drive forward) to move clear of
> the track? Obviously there is then an insurance claim to be settled, but
> that is trivial compared with the risk of a collision.
>
>
> Seems that in this case they were able to get NR staff to control the
> barrier manually to raise it, and get things sorted within an incredible
> short time of 25 minutes. I imagine NR staff must have been working
> at/near the crossing at the time. I believe that crossing is a
> recognised place for road/rail vehicles to transition between road and
> rail.

For a full barrier crossing in the UK, the crossing sequence is
activated by a signaller who has a view of the crossing, either locally
or via CCTV, and the crossing is protected by signals on the railway
that are only cleared once the signaller is certain the crossing is clear.

From the process I observed when I visited a signal box controlling a
CCTV crossing, the signaller has to take three separate steps: first,
they activate the lights/audible warning. Once the red flashing lights
are on, they then check the crossing to be clear and then activate the
barriers to drop, while monitoring the crossing. Once the barriers are
down and the crossing is clear, they finally clear the railway signal.

In this type of crossing, for the barrier to come down on top of a
vehicle, that would require the vehicle to far enough from the crossing
to not be visible after the lights have cycled from amber to flashing
red, so that the sgnaller had started the barrier phase, and enter the
crossing as the barriers are dropping. In the event this happened, the
signaller is able to immediately command the barriers to raise, which
they will do provided the collision with the vehicle has not damaged the
mechanism rendering them inoperable. Unless the signaller reclessly
breaks the rules, at no point would the signals be cleared for the
trains, so the risk of a collision is minimal.

AHB crossings (automatic half-barrier) are entirely different, as their
operation is entirely automatic, and the crossing sequence begins after
the train has already approached too close to stop (in the interests of
minimising the crossing closed time). In that case, it could be only a
few seconds between barriers dropping and train crossing. Due to this
inherent high risk, that sort of crossing is only installed on minor
roads where certain conditions are met to mitigate the risk of things
like limited visibility.

This kind of operation for full barrier crossings ensures that they are
reasonably safe, but has the drawback that due to the full operation of
the lights and barriers needs to happen before the incoming train
reaches the distant signal related to the signal protecting the
crossing, the time the road is blocked to road traffic for the passage
of a train is quite long. History has suggested, though, that drivers
can not be trusted to behave safely with a level crossing cycle that
faster but higher risk.

Robin

On Tue, 5 Mar 2024 09:30:19 +0100, Bob <bob@domain.com> wrote:

<snipped>
>
>For a full barrier crossing in the UK, the crossing sequence is
>activated by a signaller who has a view of the crossing, either locally
>or via CCTV, and the crossing is protected by signals on the railway
>that are only cleared once the signaller is certain the crossing is clear.
>
> From the process I observed when I visited a signal box controlling a
>CCTV crossing, the signaller has to take three separate steps: first,
>they activate the lights/audible warning. Once the red flashing lights
>are on, they then check the crossing to be clear and then activate the
>barriers to drop, while monitoring the crossing. Once the barriers are
>down and the crossing is clear, they finally clear the railway signal.
>

Many full-barrier crossings now have obstacle detection equipment so
CCTV isn't required.

>In this type of crossing, for the barrier to come down on top of a
>vehicle, that would require the vehicle to far enough from the crossing
>to not be visible after the lights have cycled from amber to flashing
>red, so that the sgnaller had started the barrier phase, and enter the
>crossing as the barriers are dropping. In the event this happened, the
>signaller is able to immediately command the barriers to raise, which
>they will do provided the collision with the vehicle has not damaged the
>mechanism rendering them inoperable. Unless the signaller reclessly
>breaks the rules, at no point would the signals be cleared for the
>trains, so the risk of a collision is minimal.

I'm not sure that your second step is always present. My understanding
of CCTV-controlled crossings is that the signaller starts the
sequence. The lights and sirens operate. After a while the barriers
lower with no further action required by the signaller. Once the
barriers are down and secured an indication is given to the signaller
who checks the camera then clicks to confirm the crossing is
unobstructed and allow the signals to clear. With obstacle detection
this is all automatic (so far as I understand it), the decision made
by the equipment.
>
>AHB crossings (automatic half-barrier) are entirely different, as their
>operation is entirely automatic, and the crossing sequence begins after
>the train has already approached too close to stop (in the interests of
>minimising the crossing closed time). In that case, it could be only a
>few seconds between barriers dropping and train crossing. Due to this
>inherent high risk, that sort of crossing is only installed on minor
>roads where certain conditions are met to mitigate the risk of things
>like limited visibility.

Yes, and that's what's shown in the article that the OP linked to (and
this is confirmed in the sectional appendix, it's a crossing of type
AHBC-X, automatic half-barriers bidirectional). How long do you have
after the closing sequence starts? 28s is the figure that springs to
mind. So the most likely explanation for the lorry fouling the
barriers is that the driver tried to race the barriers. He's lucky he
hadn't driven a few meters further.

There does seem to be a risk when trains approach from each direction.
Suppose said lorry was stopped by the crossing, a train passed, then
the barriers were raised. He was a bit slow off the mark, had a heavy
load and approached the crossing up a slope. It could take a long time
to clear the crossing. I assume that there are treadles to stop the
barriers from lifting if something is coming the other way but has yet
to strike in and start the lowering sequence.
>
>This kind of operation for full barrier crossings ensures that they are
>reasonably safe, but has the drawback that due to the full operation of
>the lights and barriers needs to happen before the incoming train
>reaches the distant signal related to the signal protecting the
>crossing, the time the road is blocked to road traffic for the passage
>of a train is quite long. History has suggested, though, that drivers
>can not be trusted to behave safely with a level crossing cycle that
>faster but higher risk.
>
>Robin

On 04/03/2024 20:25, NY wrote:
> Leaving aside that this shouldn't be possible if the driver has obeyed
> the yellow and red lights of the wig-wag,

If the barrier is operating correctly.