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Level Crossings
Posted: Thu May 17, 2012 9:16 am
by 52A
Does anyone know what a L&LW crossing is?
Re: Level Crossings
Posted: Thu May 17, 2012 10:40 am
by Mickey
Deleted
Re: Level Crossings
Posted: Thu May 17, 2012 4:27 pm
by majormagna
I've never heard of a L&LW Crossing... Can We hear it in some form of context?
Re: Level Crossings
Posted: Thu May 17, 2012 6:02 pm
by 52A
Neither have I! It was mentioned in a 1920 coroner's court after the death of a farmer. I think it refers to an occupation crossing.
Re: Level Crossings
Posted: Thu May 17, 2012 6:52 pm
by Percy Main
I think crossings were sometimes named (or described on maps) after the company (or perhaps individual) who owned or used them.
Re: Level Crossings
Posted: Sat May 19, 2012 8:20 am
by Mickey
Deleted
Re: Level Crossings
Posted: Sat May 19, 2012 4:04 pm
by majormagna
Percy Main wrote:I think crossings were sometimes named (or described on maps) after the company (or perhaps individual) who owned or used them.
I think this is probably the best explanation for this, and the crossing was named after a company/hamlet etc. which it served.
Re: Level Crossings
Posted: Sat May 19, 2012 5:30 pm
by geofrancis
Somewhere on a district I once worked, there was a set of Level Crossing gates operated by the
signalman from the Box which was adjacent to the road crossing.
The gates were controlled by a big coiled flat spring which was geared and on a rachet under the signalbox, the signalman would wind up on a large wheel, when loaded he would open the gates using levers to release the spring, the spring would unwind closing the gates, the operation was reversed to close them. When closing. the pedestian gates he locked with another lever.
I,m going back a few years, and can,t remember where it was, maybe South Yorkshire or Lincolnshire.
Geofrancis
Re: Level Crossings
Posted: Sat May 19, 2012 5:55 pm
by strang steel
Micky wrote:Personally i've never liked level crossings that much the exception being 'Ware crossing' on the Broxbourne-Hertford East branch.
I recall being up the front on a number of occasions on a class 31 as a secondman on a Kings Cross-Cambridge train back around 1974/75 and after passing through Aswell station at 60mph there was that long straight open section of the line heading towards Royston station where in the far distance you would see a automatic half barrier crossing still with the barriers up and the odd motor vehicle crossing over it as you was approaching it at speed!!.
Then maybe about 1/2 a mile from this crossing while you was doing about 60mph you would finally see both the automatic half barriers going down (at last).
That does seem rather scary Micky, especially so given some idiot drivers' preference for weaving around barriers at the last minute.
I would have thought that the barriers ought to be down before a point which coincided with the stopping distance of an average sized train moving initially at the maximum line speed.
Re: Level Crossings
Posted: Sat May 19, 2012 7:55 pm
by Bryan
It all comes down to the time set for the barriers to come down before the train arrives.
Too long and drivers start weaving. Others on here will give more details if needed.
Unfortunately if you have a long straight stretch with a crossing you are quite likely to see traffic moving across as you approach. No different to traffic lights on a major road except your braking distance is a wee bit more.
However would you rather see that traffic at a distance coming to a stop as the barriers descend or would you prefer to come round a curve blind hoping that the traffic has cleared?
What's the difference?
Re: Level Crossings
Posted: Sat May 19, 2012 10:46 pm
by StevieG
Many a driver will have had similar experiences to Micky's concerning automatic half-barrier crossings.
One point of their introduction (the first examples have been with us for something like 50 years now; versions had already been used for quite a time on the continent) was to reduce road closure times, and AFAIK they tend (provided no equipment defects have been self-diagnosed and alarmed to the supervising signaller) to not normally be interlocked with signalling.
So the relatively short road closure times (I think, around 40 seconds minimum between ambers coming on and a train entering the crossing for trains moving at fastest permitted speed at the crossing) are thus made possible.
But it does mean that safe use of the crossing is more reliant on the road users, because, if the line is clear of trains to and sufficiently far beyond the crossing that signals can be at 'proceed', and any signals involved in that stretch beyond the crossing, including those directly signaller-controlled (colour-light signals, including those protecting the crossing [the nearest one before reaching the crossing on any line] do not have to be normally signaller-controlled just because an automatic crossing is there, and can instead work automatically), are showing proceed, then the protecting signals can also indeed be at all-clear while the crossing is open to road, so in those circumstances trains can legitimately keep coming, whatever is going on at the crossing.
Permitted linespeed over an AHB crossing cannot exceed 100mph: Any higher at a level crossing and the arrangements have to be signaller-control with full road closure before signals can be cleared.
In the straight track tale from Micky, if vehicles 'weave' sufficiently soon after the barriers drop, and the driver sees it, he/she can at least be slowing down if they think it prudent, but the ability to do so is much reduced or does not exist in the curved approach+hope/no long-distance view scenario (train drivers are not expected to slow down on an unsighted approach to such crossings if not required to do so by published/signed/signaller-instructed speed restriction, on a 'just in case' basis.
AHB crossings can exist on traditionally signalled lines as well as modernised ones, and quite a few are 'in section' between, and completely independent of, mechanical style signal boxes and their signalling (save that each is surpervised [have the communications, operating indications and alarms] by the signaller in one of the adjacent boxes).
Conversely, at any crossing where the road becomes completely closed off by barrier(s) or gates, then the crossing is interlocked with signalling and is signaller-controlled/supervised (or is looked after by a crossing keeper, or is traincrew-operated; where there may be no signals).
Re: Level Crossings
Posted: Sat May 19, 2012 11:57 pm
by 52D
Many moons ago when pussy was a kitten i cycled out to Falloden crossing just north of Christon Bank to see this wonderous new crossing. I shat my pants watching Deltics and the like thundering past a half open gate whereas the week before there were old fashioned gates closed fully across the road with a big black handwheel.
Even when i graduated to cars i was always wary at this crossing and Warkworth further south it seemed that the trains were on you in no time after the bells started ringing.
Personally im glad they have been replaced with cctv operated full length barriers although i do concede if drivers obey the rules there should be no risks i just couldnt take to half barriers.
Re: Level Crossings
Posted: Sun May 20, 2012 11:12 am
by 52A
Yes I think 52E is right, probably the local name for an occupation crossing, the scene of many a mishap over the years. I was trundling north at Fallodon one night and thought that a car was rather near the line, when we went past it was rather near, the barrier was resting on the bonnet! One way to learn what white lines are painted on the road for.