Kirknewton Level Crossing Question.

[InOban]

The current building of a new housing estate next East Calder (Calderwood ) was meant to be accompanied by the construction of a much larger car park at Kirknewton Station. However this has been abandoned as the only feasible site was on the South side of the line and would undoubtedly have generated dangerous behaviour by late-running commuters rushing for their train. They're getting a bus service instead.

 

[43066]

This is why UK trains are fitted with safety systems, to prevent human error.

On train safety systems on the classic network: TPWS/AWS/DRA etc. certainly don’t prevent human error.

 

[Mag_seven]

On train safety systems on the classic network: TPWS/AWS/DRA etc. certainly don’t prevent human error.

Indeed - they are there to mitigate the consequences of human error.

 

[dangerousdids2]

To mitigate against human error. TPWS is not guaranteed or designed to prevent a signal being passed at danger, it’s there to mitigate the risk.

That maybe so yeah but the crossing will close as the train passes the signal at danger. In this day and age there's no way that crossing will remain unprotected from that risk.

 

[mad_rich]

This seems completely unremarkable to me?

The T&W Metro has this at all its level crossings (which have no barriers btw). Platforms in both directions are before the level crossing, and so all trains will be stopped at a red signal, and the only way they can proceed is when the crossing has been activated.

 

[43066]

Indeed - they are there to mitigate the consequences of human error.

Yes exactly. This is why there’s still so much emphasis placed on non technical skills etc. and procedures put in place to avoid mistakes. The railway is very safe as a result, but I think there’s a bit of a misconception amongst the public that non existent levels of automation and infallible safety systems somehow prevent incidents - very much not the case.

That maybe so yeah but the crossing will close as the train passes the signal at danger. In this day and age there's no way that crossing will remain unprotected from that risk.

For the crossing in this thread (which sounds like it’s CCTV controlled), that’s true. But the majority of level crossings in use on the network aren’t interlocked with signals, and rely on the users to follow instructions. Many have gates entirely operated by the user, or no gates at all!

 

[Railsigns]

For the crossing in this thread (which sounds like it’s CCTV controlled),

It's an MCB-OD crossing.

 

[norbitonflyer]

The system has to be designed on the assumption that trains will not pass red signals, otherwise nothing would ever move. As illustrated by the accident at Salisbury last year, things can go wrong with that.

The main mitigation is always to have an overlap distance or safety margin beyond the signal. I am not familiar with the station in question, but it sounds like the signal protecting the level crossing is at the end of the platform. The only way to increase the safety margin would be to move the signal further away from the crossing, but that would mean the train couldn't enter the station until the signal had cleared, which in turn means the crossing barriers would have to be down before the train entered the station. This would lead to the road being closed for much longer, which is unlikely to be popular with road users. (North Sheen is an example where the gates are down for a very long time when a down stopping train is due)

Alternatively, you could move the station platform further away from the road, but this would mean rebuilding the station, not to mention inconveniencing passengers who would have a longer walk from the road to get to it. Some stations have been rebuilt with staggered platforms, so that trains in both directions cross the crossing before stopping at the respective platforms.

 

[snowball]

I think the signal is visible in this GSV:

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

www.google.co.uk

(The link to Google Street View looking towards the station from the level crossing. After clicking on the link you can use GSV to navigate the local road system or switch to overhead view.)

 

[Ediswan]

I think the signal is visible in this GSV:

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

www.google.co.uk

(The link to Google Street View looking towards the station from the level crossing. After clicking on the link you can use GSV to navigate the local road system or switch to overhead view.)

Pan left and right and there are small metal triangles with a sign "Do not obstruct this reflector". Facing these, across the road, is an anonymous round white housing. Is that some kind of obstruction detection system ?

 

[norbitonflyer]

I think the signal is visible in this GSV:

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

www.google.co.uk

(The link to Google Street View looking towards the station from the level crossing. After clicking on the link you can use GSV to navigate the local road system or switch to overhead view.)

It rather looks as if the platform used to be longer (as the other one still is). Possibly shortened specifically to allow the platform end signal to be positioned with a safety margin from the crossing.

Look how close these signals were to the level crossing. (The single arm in the foreground in the first picture allows shorter trains to stop short of the fouling point with the through tracks, the double one further on allowed longer trains to stop in a position fouling the through line so the rear of the train would be on the platform, but still short of the level crossing). Note also the signals beyond the crossing, facing the other way, are also very close to it, allowing a short train to stop between the two crossings.

Or here

 

[CAF397]

The system has to be designed on the assumption that trains will not pass red signals, otherwise nothing would ever move. As illustrated by the accident at Salisbury last year, things can go wrong with that.

The main mitigation is always to have an overlap distance or safety margin beyond the signal. I am not familiar with the station in question, but it sounds like the signal protecting the level crossing is at the end of the platform.

Under signalling standards the overlap beyond the signal is a nominal 200 yards. This has to be clear of obstructions for the signal in rear to display a proceed aspect upto the signal in question.

For the purpose of signalling regulations, a level crossing in the overlap of a signal is not classed as an obstruction, and so that's why you can have a train stopping at a red signal with effectively a lorry with a shipping container sat on the crossing a few metres from the train.

As mentioned, safety systems are in place to mitigate against a SPAD.

 

[Somewhere]

A lot (all?) level crossings with a stop signal have a teadle, which a train passing the signal at danger will activate, causing the road lights to activate

 

[CarrotPie]

Pan left and right and there are small metal triangles with a sign "Do not obstruct this reflector". Facing these, across the road, is an anonymous round white housing. Is that some kind of obstruction detection system ?

Yes, probably LiDAR.

 

[stuving]

Yes, probably LiDAR.

The white blob is a Honeywell radar (YD136 AFAIK). The laser scanners (Optex Redscan) are the things between the tracks on both sides of the road, and you'd expect them to use the reflectors. Network rail announced the installation of "cutting edge object detection technology" in 2011, which is very early for an MCB-OD. The text says this is "recently approved technology", but it was a couple of years before the equipment choice was confirmed, so I'm not 100% sure whether what was put in then is what we see now.

 

[Dieseldriver]

That maybe so yeah but the crossing will close as the train passes the signal at danger. In this day and age there's no way that crossing will remain unprotected from that risk.

Yes but how quickly do you think a train will reach the crossing after having passed the red signal at any sort of speed?

 

[scotraildriver]

Yes but how quickly do you think a train will reach the crossing after having passed the red signal at any sort of speed?

If a train was travelling at any sort of speed approaching a red the overspeed sensors would catch it long before the signal.

 

[GB]

If a train was travelling at any sort of speed approaching a red the overspeed sensors would catch it long before the signal.

TWPS is designed to mitigate SPADS (ie stop the train within the overlap distance), not stop them completely. If a train was going fast enough and a level crossing was within said overlap it could reach the crossing with little to no warning...as happened in the Sandwich incident a couple of months ago, allthough that didn't involve TPWS.

 

[CarrotPie]

TWPS is designed to mitigate SPADS (ie stop the train within the overlap distance), not stop them completely.

...which is the purpose of TPWS+ and its associated OSSs.

 

[dangerousdids2]

Yes but how quickly do you think a train will reach the crossing after having passed the red signal at any sort of speed?

What's the likelihood of train that's scheduled to stop blasting towards the platform at 80mph?
At say 20 mph the train will stop quite quickly. It's not the 1950s trains have good brakes these days.

 

[Lucan]

in the event of a stopping train failing to stop at the Red signal/ in the platform and continuing as far as the road, it would cross that with the barriers raised and no lights flashing

Ouch. Sounds as bad as a HGV failing to stop for red lights at a road junction.

 

[norbitonflyer]

Ouch. Sounds as bad as a HGV failing to stop for red lights at a road junction.

And far less likely

I can see how you would get a fright at night though, if you don't see the train until you are on the crossing and see the train headlights!

As discussed on the Motspur Park thread, the old-style swing gates would make the situation less disconcerting.

 

[dangerousdids2]

Doing a further bit of reading on this crossing it was once considered one of the most dangerous crossings in Scotland. With quite a few accidents and fatalities. Network rail installed a sensor that scans for objects obstructing the crossing, it's linked to the signalling system and will stop trains if the line isn't clear. Well display a signal at danger anyway.

As for tpws I thought that any trains approaching the yellow aspect faster than the required stopping speed would apply emergency brakes. It looks like that's used in some areas but not everywhere.

 

[Somewhere]

If a train was travelling at any sort of speed approaching a red the overspeed sensors would catch it long before the signal.

Only if there are overspeed sensors. They are few and far between. Most TPWS grids are there to stop a train crashing into another train, not to stop a train crashing into something on a level crossing

 

[Chris Hamilton]

Kirknewton LC is of the MCB-OD type, as is Kingsknowe, which is of a very similar design a few miles towards Edinburgh. The only difference being the Limit of Shunt (at Kingsknowe) and differing treadle type/layout. Both have junctions just ahead, are at stations, and have a mix of traffic. They were both upgraded from AHB nearly 10 years ago due to the horrendous amounts of misuse they experienced.

If the signaller at Workstation 4 sets a route up to the signal protecting the crossing, then the train will be brought to a stand and the driver will have to use the plunger to activate the crossing (unless the signaller intervenes, which they may do if there is a problem). If the signaller sets a route through the crossing and also indicates that the train is not stopping, then the barriers will be lowered in the normal sequence. *Note, that for the signaller, you can also read ARS (Automatic Route Setting). The system will then (either by plunger or signaller) activate the sequence, including the use of Obstacle Detection to prove the absence of any obstruction on the railway. It is very sensitive, and will detect anything from a blowing plastic bag to a vehicle, to a very slight deflection of the booms (usually because a vehicle has clipped them).

A train approaching either is brought to a stand through the normal sequence of approach, including the use of Overspeed sensors for the TPWS. Overrun treadles will place the barriers into failed mode and immediately illuminate the flashing red lights (which as all motorists know means "DO NOT PASS" under any circumstances). If a train does overrun the signal, it will be at relatively low speed because it will either be having had a full emergency brake application from linespeed at the overspeed sensor, or has somehow slipped past the trainstop sensor, at which point it will have been doing a lower speed anyway.

In my 17 years signal engineering experience, Kirknewton and Kingsknowe have the best Hi-Def, night vision equipped, CCTV systems I've ever encountered, and have led to many prosecutions and the ability to disprove allegations against our equipment, which is always the first line of defence following any visit from the BTP. The combination of that, with our data recorders, ScotRails station and on-board CCTV, makes me wonder why anyone would risk it.

But to answer the OP, its a very normal sequence of operation and while less common now, LX at stations used to be a very regular feature of our network. But I guess it could be jarring if you weren't expecting it. Wait until you experience trains occupying both platforms as you drive over.