Question about level crossing barrier timings

[Javelin_55]

Without going off course, trains between marlow and bourne end were cancelled last night. The reason given "a road vehicle stuck on a level crossing"

There are 2 single barrier crossings and one gate that has to be opened by hand on this stretch of line.

The car got stuck because it mistakenly drove off the level crossing and on to the track. The owner couldn't reverse back on to the crossing due to the height of the anti-trespass wooden slatting.

 

[al78]

For the purpose of clarity, I only use "signaller" below, but the same applies to crossing keepers.

As per the earlier reply, for a manually controlled full barrier (MCB) crossing (either local to the signal box, crossing keepers box or monitored by CCTV and controlled remotely), it's the duty of the signaller to close the crossing to road traffic in sufficient time such that a train does not receive restrictive aspects. In other words, the train driver will only see green signal aspects, and hence can drive at the line speed or the maximum speed of the train (whichever is the lower figure).

If the railway line side signals are each spaced one mile from each other, in a three aspect signalled area, that means the signaller will start the close crossing procedure when the approaching train is around three to four miles away. This assumes the line speed is 60MPH, hence the train is taking 60 seconds to travel one mile. For higher speeds, the close crossing procedure needs to start even earlier.

    S1 Green   S2 Green   S3 Yellow  S4 Red
    |-OOO      |-OOO      |-OOO      |-OOO 
------------------------------------------|-|---
------------------------------------------|-|---
                                         Crossing

Above is the signal aspect sequence assuming no trains in the area and the crossing is open to road traffic. In order to ensure that the train driver does not see a restrictive aspect (that is any other than green), the signaller has to have the barriers fully lowered before the train passes signal S2. Hence the signaller will want to start the close crossing procedure as soon as they see a train approaching signal S1 or if the speed is higher, the previous signal.

I hope that helps to explain why it takes four to six minutes between a road user seeing the amber and red road lights, the barriers lowering and then a 'long wait" before the train appears.

Please note that the above is but one possible example, and for each crossing, in the real world, there are many other factors. Such as stations and junctions that mean a particular crossing has more complexities.

Thanks, that is a very nice schematic of what is going on outside the road user's vision. Part of my curiosity for the large lag is because in the past, the barriers would go down and a train would pass in no more than half a minute (from memory). An earlier post which explains the upgrade from half to full barrier and the treadle which originally triggered the barriers being between Littlehaven and the crossing (it cannot have been more than a few hundred meters up the line) also gives a good explanation why.

It is not a significant issue for me, at worst a mild irritation. After a full day at work immediately followed by an evening meeting, and having been on duty at work and out of the house for 14 hours I was tired and keen to get home. Problem with Horsham is it can be tedious to cross the town from Roffey to BBH as there is either a level crossing to negotiate or badly timed traffic lights on the Albion Way.

 

[Ken X]

It's even better now the Worthing Road is shut for twelve weeks. They are going to start works on the Guildford Road for two weeks outside the Co-op on Monday to compound the challenges. Probably better to head north, round Giblets Way and down North Heath Lane.

Enjoy

 

[TSG]

Ironically, the much busier A248 level crossing further along towards Shalford only closed about half a minute before the train passed, because, although it is far busier, it is only an AHB!

Tangley crossing is on the far busier A248, but with no give way junctions in proximity, allowing traffic to flow smoothly across. Chilworth feeds into a triangle with a pair of give way T junctions, where traffic waiting to join the busy A248 has a greater risk of queuing across the crossing. Chilworth crossing is also at the end of the station platforms, which increases the risk of pedestrians making a run for it across the AHB considerably. The choice of crossing is not random but there are more factors to consider than simply the traffic level.

 

[Falcon1200]

Stowmarket has no overlap after the down platform starting signal either.

But that doesn't matter, surely?!! Trains can be routed to a signal at danger immediately before a level crossing with it still open to road traffic. Some crossings, such as Kirknewton between Edinburgh and Carstairs, had (and AFAIK still have) stopping and non-stopping modes, for the first the barriers do not lower until the driver of an Up train stopped in the station operates a plunger. Which has resulted in motorists reporting a train hurtling towards them as they drove over the crossing!

 

[dk1]

But that doesn't matter, surely?!! Trains can be routed to a signal at danger immediately before a level crossing with it still open to road traffic. Some crossings, such as Kirknewton between Edinburgh and Carstairs, had (and AFAIK still have) stopping and non-stopping modes, for the first the barriers do not lower until the driver of an Up train stopped in the station operates a plunger. Which has resulted in motorists reporting a train hurtling towards them as they drove over the crossing!

Yes a level crossing isn’t always classed as an obstruction but trains should not be signalled unnecessarily onto a red signal & would cause delay. Best to give us a green from the outset.

Stowmarket & Regent Street are operated by the attendent at Stowmarket as requested by Colchester PSB.

 

[Falcon1200]

Best to give us a green from the outset.

Of course, and I suspect a reason Kirknewton has the arrangement it does is because of its status as one of Scotland's most-abused crossings! This has presumably changed however since its conversion from AHB to full barriers with OD, I am not sure whether the stopping/non-stopping arrangement still exists, and of course it would not be suitable everywhere.

 

[dk1]

Of course, and I suspect a reason Kirknewton has the arrangement it does is because of its status as one of Scotland's most-abused crossings! This has presumably changed however since its conversion from AHB to full barriers with OD, I am not sure whether the stopping/non-stopping arrangement still exists, and of course it would not be suitable everywhere.

MCBODs are pretty well timed to give trains clear signals yet only stop road traffic for the least amount of time necessary. We used to plunge at the likes of Woodbridge for ABCL crossings but that has stopped now. Consideration was given to a plunger at Wymondham (down) for Browick Road AHBs in 2012 but deemed too complex in getting agreement between NR, GA & unions as to whether they could insist on guard or driver taking on the additional responsibility.

 

[Railsigns]

This has presumably changed however since its conversion from AHB to full barriers with OD, I am not sure whether the stopping/non-stopping arrangement still exists, and of course it would not be suitable everywhere.

Kirknewton MCB-OD (and Kingsknowe MCB-OD) does have stopping/non-stopping controls for Up direction trains, selected by the automatic route setting. Drivers of stopping trains need to operate a plunger on the platform to start the crossing sequence.

 

[Falcon1200]

Drivers of stopping trains need to operate a plunger on the platform to start the crossing sequence.

Thanks, I wasn't sure if it was still in use at Kirknewton; It does of course reduce the time the crossing is closed to the road (for an Up stopping train), IIRC something which was commented on/complained about after the crossing's upgrade!

 

[al78]

It's even better now the Worthing Road is shut for twelve weeks. They are going to start works on the Guildford Road for two weeks outside the Co-op on Monday to compound the challenges. Probably better to head north, round Giblets Way and down North Heath Lane.

Enjoy

The closure of Worthing Road means I have to leave a bit earlier to get to the station in good time in the morning because the traffic that used to go that way is now trying to get into Horsham along the Guildford Road (the next junction northbound along the A24), and frequently it is stop-start traffic from Farthings Hill to the Bishopric (about a mile). It is even worse when people park on the double yellow lines close to the Bishopric traffic lights blocking the left turn lane, meaning everyone has to queue behind the traffic wanting to turn right, for which the green phase is much shorter than for left turning traffic. Given there are roadworks on the Warnham Road which is the next junction up again, roadworks on the Guildford Road is going to make it awful for anyone trying to get into Horsham from the south or west. On a bike I at least have the option of going through the Tesco car park and the shared use facility that leads to Hills Farm Lane.

 

[Bikeman78]

Thanks for the interesting replies, I guessed there was a logical reason. I hadn't noticed that crossing had been upgraded but I wasn't really paying attention to the barriers beyond waiting for them to rise, but thinking about it I recall years ago it was half barrier.

The most notorious crossing in Horsham used to be Rusper Road where it passes Littlehaven station. The station platforms could only accommodate four carriage trains and anything longer would straddle the crossing whilst unloading and loading at the station. Trains coming from Horsham that stopped at the station also triggered the barriers so it was kind of a worst case scenario for having to wait. If you were unlucky, you could be waiting around 12 minutes as three trains go through the crossing, two of them stopping at the station in different directions with the Horsham bound one straddling the crossing. The crossing was upgraded and the platforms at Littlehaven extended to accomodate eight carriage trains so the crossing is a lot better now.

Unfortunately, shortly after the platforms were extended to eight cars, the trains extended to 12 cars. Happily the down platform has now been extended to 12 cars.

 

[Deepgreen]

The car got stuck because it mistakenly drove off the level crossing and on to the track. The owner couldn't reverse back on to the crossing due to the height of the anti-trespass wooden slatting.

Another sat-nav follower?

 

[Taunton]

get the barriers down now as there is a gap, rather than waiting until the perfect moment and finding you have a load of farm tractors nose-to-tailing across.

I think that's a pretty unlikely situation to envisage! Rather more common is an emergency ambulance coming along and the barriers have been put down early.

 

[Flying Claret]

But that doesn't matter, surely?!! Trains can be routed to a signal at danger immediately before a level crossing with it still open to road traffic. Some crossings, such as Kirknewton between Edinburgh and Carstairs, had (and AFAIK still have) stopping and non-stopping modes, for the first the barriers do not lower until the driver of an Up train stopped in the station operates a plunger. Which has resulted in motorists reporting a train hurtling towards them as they drove over the crossing!

This happens at Huncoat from time to time. Conversely when the barriers are up, it feels unnerving/counterintuitive standing on the platform, seeing railway signal on green while cars are crossing.

 

[joebassman]

Trouble with Stowmarket particularly down road is that even though it’s a stopping train priority is given to allow trains to have a green signal just after Needham Market.

A lot of trains don't stop at Stowmarket. There are 2 trains every hour from London to Norwich and only one of those trains stops at Stowmarket. Plus a lot of freight trains pass through Stowmarket. I guess they don't discern between the trains stopping and not stopping.

Without going off course, trains between marlow and bourne end were cancelled last night. The reason given "a road vehicle stuck on a level crossing"

There are 2 single barrier crossings and one gate that has to be opened by hand on this stretch of line.

Why do some crossings only have half barriers, Haughly being one?

That little devil inside my head once said, 'You could just drive around that barrier.' Obviously, I would never be stupid enough to actually do this and right after the thought entered my head a train doing, I would guess, about 90-100 shot through.

Unfortunately, some people do not appear to have enough common sense to ignore the little urchin that chatters away in the skull.

 

[66701GBRF]

A lot of trains don't stop at Stowmarket. There are 2 trains every hour from London to Norwich and only one of those trains stops at Stowmarket. Plus a lot of freight trains pass through Stowmarket. I guess they don't discern between the trains stopping and not stopping.

Most passenger trains do stop at Stowmarket. It is only the 1 intercity service in each direction per hour that doesn't (not including freight). I'm going to assume the annunciator point for down road services is before Needham Market which is why the barriers are down longer in some circumstances. Unless crossings are fitted with specific stop/non stop controls crossing keepers are told not to differentiate between stopping or not stopping services...ie, once the call to lower the barriers is received you should lower them regardless.

Why do some crossings only have half barriers, Haughly being one?

Dictated by risk factors such as level of rail and road traffic.

 

[CarrotPie]

Why do some crossings only have half barriers, Haughly being one?

Money.

 

[LAX54]

But that doesn't matter, surely?!! Trains can be routed to a signal at danger immediately before a level crossing with it still open to road traffic. Some crossings, such as Kirknewton between Edinburgh and Carstairs, had (and AFAIK still have) stopping and non-stopping modes, for the first the barriers do not lower until the driver of an Up train stopped in the station operates a plunger. Which has resulted in motorists reporting a train hurtling towards them as they drove over the crossing!

Older signalling systems can do this, but the newer H&S safety regulations mean that if there is a crossing and its at the end of the platform, the crossing has to be clear, you can run in on a red, but in most, not all, cases the barriers will still be down on approach.
Resignalling on the Clacton and Felixstowe and Wherry lines have meant signals are now in bizarre locations, or need to be showing a proceed aspect to meet 'regulations'

 

[Railsigns]

Why do some crossings only have half barriers, Haughly being one?

The half-barrier crossings operate automatically, so there's no check that the crossing is unobstructed before a train can approach. Half barriers are used to avoid trapping vehicles on the crossing when the barriers come down.

 

[LAX54]

A lot of trains don't stop at Stowmarket. There are 2 trains every hour from London to Norwich and only one of those trains stops at Stowmarket. Plus a lot of freight trains pass through Stowmarket. I guess they don't discern between the trains stopping and not stopping.


Why do some crossings only have half barriers, Haughly being one?

That little devil inside my head once said, 'You could just drive around that barrier.' Obviously, I would never be stupid enough to actually do this and right after the thought entered my head a train doing, I would guess, about 90-100 shot through.

Unfortunately, some people do not appear to have enough common sense to ignore the little urchin that chatters away in the skull.

Haughley, level of road traffic dictates CCTV not required, although that could change in any resig design, plus if you had CCTV at Haughley, the barriers would be down a lot longer, just leaving Stowmarket on the down, and on the Up when a train is passing Cow Green or leaving Elmswell.

 

[edwin_m]

Why do some crossings only have half barriers, Haughly being one?

That little devil inside my head once said, 'You could just drive around that barrier.' Obviously, I would never be stupid enough to actually do this and right after the thought entered my head a train doing, I would guess, about 90-100 shot through.

Unfortunately, some people do not appear to have enough common sense to ignore the little urchin that chatters away in the skull.

The half-barrier crossings operate automatically, so there's no check that the crossing is unobstructed before a train can approach. Half barriers are used to avoid trapping vehicles on the crossing when the barriers come down.

This also means that signals will clear before the barriers come down*, so barriers don't need to be lowered early enough for the train to get green signals. Thus, closure times for each train are usually less than for a full-barrier crossing, which reduces the risk that drivers will be impatient enough to try driving round the half barriers.

*Exceptions exist, as discussed somewhere upthread, where there is a platform with a signal on the approach to the crossing. It can be set to keep the signal at red and the barriers up until the train is ready to depart, when the barriers have to lower before the signal can clear.

 

[Taunton]

Manor Road, nest to North Sheen station, is particularly bad - 6tph off-peak, and it is not uncommon to have three trains pass between barrier lifts, as the second is within three blocks before the first has crossed, and by the time the second has crossed, a third one following the first, is within range. The delay is longest for trains in the down direction calling at North Sheen, as they are travelling more slowly anyway and there is also the dwell time at the station itself (on the London side of the crossing). Local residents are divided over whether the halving of the stopping service at North Sheen (and Mortlake, which has a similar issue) to 2tph due to the withdrawal of the Hounslow Roundabout services, is a Bad Thing.

I've known this one at North Sheen for a long while, through I think two complete resignallings, and indeed have written about it before. Each such resignalling has made the closure time increase notably. When it had a gateman and box they were past masters at minimising time, knowing what was stopping at the platform and what was not, and the signalling was laid out specifically to suit overlaps and sighting from the box. Progressively modernised and all this seems laid to one side, all standardised stuff, road traffic will just have to fit in with what is left now.

Yes, the halving of a mainstream London suburban service here to half-hourly is a poor thing (I regularly travel to Whitton, which off-peak seems to have lost a lot of use). Has it been done to meet some more onerous H&S requirement for crossing movements?

 

[swaldman]

This happens at Huncoat from time to time. Conversely when the barriers are up, it feels unnerving/counterintuitive standing on the platform, seeing railway signal on green while cars are crossing.

Is that really allowed? Surely if the crossing is open then the signal protecting it must be red??
(not an expert)

 

[Railsigns]

Is that really allowed? Surely if the crossing is open then the signal protecting it must be red??
(not an expert)

Yes, it's allowed at AHBC crossings. The barriers will descend automatically when a train approaches.



(Image shows a car on Shepreth level crossing and a green railway signal)

 

[stevieinselby]

Why do some crossings only have half barriers, Haughly being one?

Less disruptive to road traffic.

With a full-barrier crossing, the barriers need to come down 2–3 minutes before the train arrives (assuming it is running at linespeed), in order to give time to check there are no vehicles stranded on the crossing before the signal is cleared for the train.
With a half-barrier crossing, it is assumed that any vehicle on the crossing will be able to exit and so there is no signal control for trains, and so the barriers don't need to come down until the train is 20–30 seconds away.

Reducing the time the barriers are down by up to 5 minutes on each cycle makes a big difference to road traffic!

 

[dk1]

A lot of trains don't stop at Stowmarket. There are 2 trains every hour from London to Norwich and only one of those trains stops at Stowmarket. Plus a lot of freight trains pass through Stowmarket. I guess they don't discern between the trains stopping and not stopping.

Yes that is correct. Priority is for trains to arrive on green/least restrictive signals wherever possible.

 

[Flying Claret]

Is that really allowed? Surely if the crossing is open then the signal protecting it must be red??
(not an expert)

Happens all the time at Huncoat. I assume the preceeding signal is set to red...

 

[Railsigns]

Happens all the time at Huncoat. I assume the preceeding signal is set to red...

That doesn't ring true. Huncoat is an MCB-OD level crossing, so the protecting signal (PN401) is interlocked and won't clear unless the barriers are down and the crossing is proved clear (the control table confirms this). The *preceding signal (PN403) is an automatic signal.

 

[Tester]

Is that really allowed? Surely if the crossing is open then the signal protecting it must be red??
(not an expert)

[Expert here ]

Perhaps worth a quick explainer of how a vehicle can be on a level crossing with a green rail signal displayed.

The reason that crossings without full barriers can close much later than those with is that by default they are independent of signal aspects. There is no requirement to prove that the crossing is clear before a train can pass, as the exit from the crossing is always clear.

Of course there is a risk that the crossing will in fact not be clear for some reason, but up to now the balance of risk/road closed time permits it. Should that change, all level crossings will need full barrier crossing closed times. Be careful what you wish for!

An exception to the independence of signal aspects is where station Stopping/Non Stopping controls are provided (an option, not a requirement).

In this case, with Stopping selected, the signal between station and crossing will be maintained at red and the closing sequence then inhibited to allow station duties. As with all railway signalling, it is designed to fail safe.

Clearly in the photo shown, Stopping is either not selected or not provided (I'm not familiar with the actual controls).

Rest assured that there will always be EITHER a red signal between train and a non full barrier crossing OR sufficient time for the crossing to operate (with a margin) before a train can arrive at it.