Level Crossings @ Lansdowne, Sandymount, Sydney Parade: Excessive Length of Time Down

IE 222

blobert wrote: »

This is kind of what I thought the issue would be, that the system has to work for non stopping trains as well as the DARTs even though DARTs probably account for 90%+ of the trains coming through.

I'm guessing there is an overall low speed limit for this section of track also.

So how would this work, or why would it not work, in terms of improving things?

(1) I'm estimating 90%+ of the trains are DARTs and will stop in all stations

(2) Set whatever system they have for starting the barriers to close to trigger much later. Let's say at the moment it's 1.5km from the junction change it to 750m (these are just random figures)

(3) The DARTs will probably be fine as they will be stopping shortly before the junction in most cases or just after, ie they have to be going slow at the junctions.

(4) In the case of commuter/other trains (the less than 10%), we reduce their speed further if needs be so that the new shorter distance from the junction is still safe, ie while going at 20kmph or whatever it is that they can still safely stop in the 750m before the junction in the very unlikely event of someone being stuck. Other point I'd make on this is we're dealing with a hugely straight length of track, ie you can see 1+km ahead, so even if someone is stuck several junctions ahead, the train driver will be able to see this from a huge distance and stop in plenty of time.

(5) I watch trains go by all day here and the commuter trains seem to always be crawling, I have no idea what the limit is but I suspect they are already going far below it so I dont think they would be affected much by a lowering of their speed. We're also talking about a 2.5km stretch of track from Lansdowne to Merrion gates so even if the speed was reduced from 30kmph to 20kmph it would make minimal difference in a journey to Rosslare or wherever. Like I say I suspect the actual average speed trains are currently traveling at on this stretch of track is well below what the limit is.

Would this work?

Finally I'd agree that the Merrion Gates bridge or digging under the tracks at the junctions would be by far the best solution. But I dont' see that happening anytime soon.

I'm thinking if it is possible to improve the situation for all the thousands of people negatively affected by the junction system as it is, while not noticeably if at all degrading the experience of the many more thousands of people using the trains, then that would be the easier fix.

It would also be easier to accomplish, ie you can sell it to Eoghan Murphy or similar as somthing he can get done to make him/Irish Rail look great with a lot less effort than building bridges/digging tunnels.

Any further advice would be much appreciated.

No, its impossible.

It doesn't work like that. You got to remember a train cant just grind to a halt the same way a car does. A train could have 100s of people onboard standing and cramped ect. unlike a car so safety needs to be at the forefront here.

Level crossings have 2 signals, the first been the warning signal, and the second I think is called the protection signal. Warning signals need to be 1.3km - 1.5km from the crossing and the protection signal needs to be no less than 200m away. In this case the warning signal is located just after Booterstown which I'm guessing doubles up as the protection signal for Merrion Gates also. The protection signal is located just before the platform. The strike in, the trigger that detects a train and begins to close the gate is determined by timeframes. The process is to start once the fastest possible train is 40 seconds away. A slowing train and then stopping train is going to skew this.

Reducing line speed will have zero effect as explained above regarding the timeframe. The current speed IIRC is 40mph on this section. DARTS reach this speed and Intercity does as well if there not been held up. The high number of crossings in close proximity slows everything down.

magicbastarder

let's say you could - with some reasonably superficial tweaks - reclaim six minutes out of every hour for cars. as in; if the gates were originally down for eighteen minutes in the hour (this is just an illustration, not based on actual gate closing times) and you reduce that to twelve, so a 33% reduction in gates being closed.
with those six extra minutes, you could expect a probable maximum of 120 cars in each direction traversing the level crossing (one car every three seconds for the six minutes), or 240 cars in both directions with a probable human capacity of around 300.
that's around 25% the capacity of a single (full) train, in one hour - and it's worth pointing out that those are numbers being inconvenienced, not being rendered unable to travel - unless the road is at full capacity for the entire time it's open.

i guess what i'm saying here is that the logical thing to do is lay on more trains, and close the level crossings for longer to facilitate this.

Idbatterim

So the gates need to be down for ages , In case someone drives into the tracks and reckons they shouldn’t get out of a car in sub 90 seconds ?! Why aren’t the luas crossings operated on the same principle ?

Vic_08

BlackandGreen wrote: »

These kinds of comments are what make this website such a crappy place to browse sometimes. The irony of calling somebody pig ignorant while talking in such a tone. The hell is your problem?
Just answer the question nicely. Not everyone is a train gazing know it all.

The only irony is that you appear not to understand the definition of ignorance.

The OP was and despite having the topic explained to him by a number of posters, still remains ignorant of how and why railway crossings do not operate how he would like them to.

I'd bet you wouldn't take kindly to someone turning up, admitting they knew nothing about your line of work and then spouting off about how you are doing everything wrong and they are here to put you straight.

Yes my response wasn't polite. Ask a polite question; get a polite response, rant about how the experts in a field you know nothing about are crap at their jobs; get put in your place.

lucernarian wrote: »

I used to be a lot more active here and it's the tone and content of nasty and priggish posts like these that drive people away. Especially on the C&T forum, it's rife with crap like this.

People who want to get a reasonable answer to something they know nothing about don't generally start by offloading a bunch of derogatory opinions of the people who run the system they wish to know about.

As is obvious from his follow up responses, he is not interested in finding out the facts, only pushing his agenda to get the crossing sequences shortened to suit himself.

lucernarian wrote: »

As for the topic... yes it's true that other countries where the same laws of physics apply, where speed limits are often higher compared to the south Dublin crossings, still have shorter durations of closure. The Netherlands especially. Why is there such a difference?

Different crossings are operated to different standards, from fully controlled like those being discussed to user operated gates with no oversight, protection or warning for trains.

This is true in Ireland as well as across Europe. In general it is the type of road and the traffic on it that will be more important than the rail traffic for determining the level of protection applied. Urban high traffic roads with mixed pedestrian, vehicle and cycle traffic will always be high on the list for maximum protection. The fact that these are also the crossings that there is also the most disturbance from lengthy closures is unfortunate but inevitable, if they were quiet with bugger all traffic they wouldn't pose as much risk having a lower standard crossing.

Like it or not the first and most important factor is safety, these crossings are about as safe as you can get short of having armed guards with rifles stopping the traffic. Unlike our roads where a casual attitude to safety and in particular an unbelievably poor adherence to stopping at red lights pervades our railways operate on the basis of being 100% safe.

By an order of magnitude the weakest link in safe railway operation is road crossings and the poor behaviour of road users, the idea of degrading the safety of some of the busiest crossings in the country to reduce inconvenience to those same road users by reducing the protections the current operations have is just not going to happen, nobody in IE would do it and the railway safety authority would not sign off on it.

Were it done and a train ploughed through cars and pedestrians on a crossing it would be the very same people like the OP demanding all and sundry responsible be crucified for putting the public in danger.

Vic_08

Idbatterim wrote: »

So the gates need to be down for ages , In case someone drives into the tracks and reckons they shouldn’t get out of a car in sub 90 seconds ?! Why aren’t the luas crossings operated on the same principle ?

Because trams run to an entirely different and much lower safety standard. They are driven by line of sight not signalling, generally run slower, are smaller and lighter, have better stopping ability AND as as a consequence do actually hit road vehicles relatively frequently.

IE 222

Idbatterim wrote: »

So the gates need to be down for ages , In case someone drives into the tracks and reckons they shouldn’t get out of a car in sub 90 seconds ?! Why aren’t the luas crossings operated on the same principle ?

No, the gates need to be down so the train doesn't have to stop or slow down.

Its actually in the motorist interest for the gates to close as soon as they can so the train can pass at line speed. A train that needs to stop or slow down for a crossing is going to take longer to clear it.

ED E

OP seems to have his head in the sand.

It can't be done
But but this
It can't be done
But but that
it can't be done
But but the other


Live with it. Move. There is not room for optimization.

magicbastarder

FWIW, i got caught at the merrion gates this morning just after 7am, and seem to have been stationary for about one and a half minutes - the train passing through was northbound, so slowing as it came past.

Utter Consternation

magicbastarder wrote: »

i know it's not an operational issue, but in terms of prioritisation, the maths is interesting. an eight carriage DART has a capacity of something like 600 or 800 people, yeah? closing a road for five minutes to get 600 people through is reasonable; especially since getting that many people over the level crossing in cars would probably take half an hour.

But, but, cars duh!!!!

bikeman1

I always find it funny, "oh God there is a massive tailback of at least 30 cars waiting for one train".

Then you remind them that there is maximum 50 people in the 30 cars, meanwhile said train will have a few hundred!!

Close up Lansdowne Rd., Sandymount, Sydney Parade. Leave Serpentine Ave. as the sole crossing with even more priority to rail and then proceed with the plans for removing the Merrion Gates. Speed up the trains and speed up the cars.

blobert

Thanks very much for the replies guys.

I certainly don't mean to come across as thinking I know better or that I am anything but very ignorant of how it works, but, I do think it's fair to say that it is at least possible, that the current system may not be 100% optimal, it would be a very rare system that is. I stand at these barriers multiple times a day waiting for minutes for trains to eventually pass at very low speeds. I don't think it's that crazy to suggest that perhaps, if the real world average train speed is very low and it's taking several minutes for the train to arrive from the barriers closing, then perhaps in some way the barriers are going down to early for the actual profile of trains going by at this very specific piece of track? Now obviously within that you have the limits of how the system works (which I fully admit I don't understand).

Couple more questions for anyone with a good understanding of this, which many of you seem to have:

No, its impossible.

It doesn't work like that. You got to remember a train cant just grind to a halt the same way a car does. A train could have 100s of people onboard standing and cramped ect. unlike a car so safety needs to be at the forefront here.

Level crossings have 2 signals, the first been the warning signal, and the second I think is called the protection signal. Warning signals need to be 1.3km - 1.5km from the crossing and the protection signal needs to be no less than 200m away. In this case the warning signal is located just after Booterstown which I'm guessing doubles up as the protection signal for Merrion Gates also. The protection signal is located just before the platform. The strike in, the trigger that detects a train and begins to close the gate is determined by timeframes. The process is to start once the fastest possible train is 40 seconds away. A slowing train and then stopping train is going to skew this.

Reducing line speed will have zero effect as explained above regarding the timeframe. The current speed IIRC is 40mph on this section. DARTS reach this speed and Intercity does as well if there not been held up. The high number of crossings in close proximity slows everything down.

Thanks, I completely understand that a train need a greater stopping distance than other vehicles and probably even greater in some conditions like leaves on track etc.

You'd mentioned that the initial signal goes off when the train is 1.3km to 1.5km away.

And this is to cover how long it might take for the fastest possible train going at the speed limit might take to stop safely going at 40mph/65kmph.

I understand this also.

However, my point is that none, or a very tiny fraction of trains are going to be going at anywhere near this speed on this 2.5km section of track. DARTS are stopping 3/4 times with several of the stops very close together. If they are managing to get to 40mph back to 0 over a couple of hundred metres it's going to be massively fuel inefficient and unpleasant for passengers. The commuter train might manage to get to this speed briefly if there is a clear section of track but it's going to have to catch up with a DART and be stuck behind it, ie again just wasting fuel. I've also never seen a commuter train doing anything but crawling along this section of track. Some late night freight train is irrelevant as it's such an outlier, limiting these few trains to a lower speed for a few km does not affect anyone to any great extent. Though as I say, I suspect the reason for the barriers closing so early is that it's set up to be safe for this outlier fast train, when the solution would be to just slow these oddities down.

So my question is, if the trains are already not going fast and you were to set a realistic speed limit (lets say 50kmph) for this section, why could you not move the initial signaling point closer from 1.5km out to somthing like 750m? I don't think anyone has answered this one yet. I assume these distances have to be varieable based on train speed, ie if you added a TGV like train to these tracks doing 200kmph+ then the 1.5km warning would not end well.

If the fastest train is able to safely stop from top speed at that limit and all DARTS etc are more comfortably, how does this not improve things?

My point is if the system is set up to cover the possibility of a train going at a much higher speed than they ever do, why can't you limit the speed (which does not affect 99% of trains) and safely lower the stopping distance?

I have no idea what the safe stopping distance of a DART/Commuter train is at 50kmph but I'm guessing it's way less than 1.5km. I found this, probably not relevant at all but, suggests a diesel commuter at 70mph/113kmph takes 816m to stop (and less in an emergency) So I'm assuming a commuter train at 50kmph or probably far less is going to be able to stop in far less than that?

https://api.parliament.uk/historic-hansard/written-answers/2002/nov/21/diesel-trains-stopping-distances

If anyone could explain why what I'm suggesting is impossible I'd appreciate it.

There's also a lot of discussion of how the train should have priority over cars. I completely agree with this. But what I'm suggesting is that, if there's a way to improve the situation for all the people stuck at barriers, while not negatively affecting the experience of the people on the trains, then I think that would be a no brainer. I also think the extent of the number of people inconvenienced by the barriers on this section of line may be greater than being suggested.

As per an example:

let's say you could - with some reasonably superficial tweaks - reclaim six minutes out of every hour for cars. as in; if the gates were originally down for eighteen minutes in the hour (this is just an illustration, not based on actual gate closing times) and you reduce that to twelve, so a 33% reduction in gates being closed.
with those six extra minutes, you could expect a probable maximum of 120 cars in each direction traversing the level crossing (one car every three seconds for the six minutes), or 240 cars in both directions with a probable human capacity of around 300.
that's around 25% the capacity of a single (full) train, in one hour - and it's worth pointing out that those are numbers being inconvenienced, not being rendered unable to travel - unless the road is at full capacity for the entire time it's open.

i guess what i'm saying here is that the logical thing to do is lay on more trains, and close the level crossings for longer to facilitate this.

This is a good point however every time a train comes by you have a buildup of traffic at 5 crossings for that one train in this 2.5km stretch not just one. So you'd be looking at x5 times your figure of extra people getting through if the barrier closed time is reduced.

I still think there are going to be more people on peak DARTs than backed up at barriers, but my point is, I think there must be someway in which you could improve the experience of the people stuck at the barriers while not negatively affecting the experience of the people on the train.

Thanks again for all the replies, both positive and negative!

end of the road

the system that exists at these crossings is the most optimal possible and there are no changes that can be made.
slowing down trains further will just take them longer to clear the crossings.
every possible outcome no matter how remote has to be considered when deciding the optimal closing time for safety reasons.
the only way to end the not really inconvenience for motorists without negatively effecting the train users is to close the crossings, otherwise motorists will just have to accept that crossing closure times are going to increase.

Del.Monte

Shure none of this traffic congestion would have happened if the 'powers that be' had been allowed to bulldoze the Eastern Bypass across Sandymount Strand and Booterstown nature reserve.

TheChrisD

blobert wrote: »

With the idea that the barriers have to be down before they enter the station in case they overrun the station, how often does that happen? Is the driver the only thing stopping the train? Why could they not just delay whatever it is that's giving the signal to close each junction till the train is nearer the station, as I said it's frequently several minutes between barrier going down and train even reaching the station.

With the train overrunning, the platforms seem to be far longer than the train, the platform at Sydney Parade is circa 200m long. Could the trains not stop 100m from the end of the platform if they wanted to have built in leeway for if they somehow overrun?

100m spare in case of an overrun is nothing, especially when we get into the gist of a wet autumn/winter and leaves on the line become a major hazard: https://www.youtube.com/watch?v=OoSgU-7BiV4

blobert

TheChrisD wrote: »

100m spare in case of an overrun is nothing, especially when we get into the gist of a wet autumn/winter and leaves on the line become a major hazard: https://www.youtube.com/watch?v=OoSgU-7BiV4

Thanks Chris, realise that waiting till the train is in the station to close barrier won't work so have moved on to my ideas above!

IE 222

Lowering the line speed will have the opposite effect to what it is your looking for. The signalling can't be relocated. Lowering the speed will only take the train longer to travel through the block.

The first warning signal is a reminder of danger ahead for the driver it doesn't necessarily mean the crossing gates will begin to close once the train has passed it.

My guess would be there is a strike in just after Booterstown for Merrion Gates followed by a second somewhere between that and the warning signal for Sydney Parade.

If the gates haven't closed on time the trains need to stop twice between Booterstown and Sydney Parade, where is the benefit in that?

blobert

IE 222 wrote: »

Lowering the line speed will have the opposite effect to what it is your looking for. The signalling can't be relocated. Lowering the speed will only take the train longer to travel through the block.

The first warning signal is a reminder of danger ahead for the driver it doesn't necessarily mean the crossing gates will begin to close once the train has passed it.

Surely the signalling can be relocated or adjusted?

It's still not clear to me how the barriers closing is activated, based on comments here I understood this to be when it crosses a certain point x distance from the junction. The distance was based on the fastest train going at the line speed.

My point was if the trains are all going well under the line speed, if you lower the line speed and thus reduce the distance needed for the train to safely stop (because the max speed is now lower) the trains can still travel at the speed they do and the barriers wont close as early.

A quick look at Wikipedia suggests this might be exactly the issue and perhaps the system Irish Rail are using is outdated?

At most crossings, the signals will activate about 30 seconds before the train arrives.The gates will be fully lowered 15 to 20 seconds before the train arrives. The gates will rise and the signals will shut off once the end of the train clears the island circuit.

This ties in to my experience everywhere in the world except on the tracks beside me

The design goal of the grade crossing predictor is to provide a consistent warning time for trains approaching a grade crossing.

Before this invention, the circuits used for activating a crossing's warning devices were very simple, activated whenever a train came within a fixed distance (hundreds or thousands of feet) of the crossing. This method required that the crossing be designed to accommodate a train approaching at the track speed limit, which leads to longer warning times for trains approaching the crossing at lower speeds. Very slow trains could have many minutes of warning time, thus delaying highway traffic unnecessarily.

Again this sounds very like what's happening here?

Any further input would be much appreciated.

IE 222

blobert wrote: »

Surely the signalling can be relocated or adjusted?

It's still not clear to me how the barriers closing is activated, based on comments here I understood this to be when it crosses a certain point x distance from the junction. The distance was based on the fastest train going at the line speed.

My point was if the trains are all going well under the line speed, if you lower the line speed and thus reduce the distance needed for the train to safely stop (because the max speed is now lower) the trains can still travel at the speed they do and the barriers wont close as early.

A quick look at Wikipedia suggests this might be exactly the issue and perhaps the system Irish Rail are using is outdated?



This ties in to my experience everywhere in the world except on the tracks beside me



Again this sounds very like what's happening here?

Any further input would be much appreciated.

I don't get why your so determined to challenge this.

How is reducing the speed and distance going to change things. Regardless of the line speed the train still needs to trigger the strike in, to close the gates, 40 seconds before it reaches the crossing or in this case the platform. The train is still going to take the same length of time to travel from point A-B. The trains reach line speed, it's not some figure they pulled from thin air. Moving the trigger point for Sydney Parade gates will likely result in trains stopping and blocking the Merrion Gates.

Your better off lobbying Eoghan Murphy to close the gates to traffic and install a footbridge instead.

IE 222

blobert wrote: »

Surely the signalling can be relocated or adjusted?

It's still not clear to me how the barriers closing is activated, based on comments here I understood this to be when it crosses a certain point x distance from the junction. The distance was based on the fastest train going at the line speed.

My point was if the trains are all going well under the line speed, if you lower the line speed and thus reduce the distance needed for the train to safely stop (because the max speed is now lower) the trains can still travel at the speed they do and the barriers wont close as early.

A quick look at Wikipedia suggests this might be exactly the issue and perhaps the system Irish Rail are using is outdated?



This ties in to my experience everywhere in the world except on the tracks beside me



Again this sounds very like what's happening here?

Any further input would be much appreciated.

I don't get why your so determined to challenge this.

How is reducing the speed and distance going to change things. Regardless of the line speed the train still needs to trigger the strike in, to close the gates, 40 seconds before it reaches the crossing or in this case the platform. The train is still going to take the same length of time to travel from point A-B. The trains reach line speed, it's not some figure they pulled from thin air. Moving the trigger point for Sydney Parade gates will likely result in trains stopping and blocking the Merrion Gates.

Your better off lobbying Eoghan Murphy to close the gates to traffic and install a footbridge instead.

lucernarian

beauf wrote: »

In fairness its a bit of naive question/premise for thread in the first place.

Who knows what you're comparing with in the Netherlands. Like with like? Budget, traffic on line? Bit of a how long is length of string.

In fairness nothing, there's no (good) reason for people to reply like assholes or speak in a way most folks wouldn't dream of doing with colleagues, customers, acquaintances or even strangers.

I think the salient part of the question is obvious. Why would a barrier need be closed for 3 mins before a train arrives while in the Netherlands I observed it closed for 90 seconds on a track that had a 100kph speed limit? Like, it's not a rhetorical question, there must be specific reasons for why this happens especially at the likes of Sydney Parade.

VANG1

What’s going to happen when the frequency of trains increases to one every 5 minutes. I presume our highly paid politicians have no plans made

lucernarian

Vic_08 wrote: »

The only irony is that you appear not to understand the definition of ignorance.

The OP was and despite having the topic explained to him by a number of posters, still remains ignorant of how and why railway crossings do not operate how he would like them to.

I'd bet you wouldn't take kindly to someone turning up, admitting they knew nothing about your line of work and then spouting off about how you are doing everything wrong and they are here to put you straight.

Yes my response wasn't polite. Ask a polite question; get a polite response, rant about how the experts in a field you know nothing about are crap at their jobs; get put in your place.

"get put in your place" Is this a schoolyard? I don't see any experts here talking about rail safety and signalling, unless they might step forward with their qualifications, or references for their knowledge?

You're also taking points made after the fact, as justification for the bitchy and mean tone of your reply (the 2nd post of this thread). I re-read the first post, I saw someone who was disgruntled on a personal level and wanted to understand more about the subject - throwing out ideas in the hope they could be discussed further. Where's the rude and ranty post you're referring to? Or is this just a handy straw man for post-hoc justifying of your rude response?

People who want to get a reasonable answer to something they know nothing about don't generally start by offloading a bunch of derogatory opinions of the people who run the system they wish to know about.

Again, can you cite where, in the first post, these derogatory comments are? If it's "it's very clearly just been done incorrectly and could proabbly be massively improved with very little effort"..... Is this honestly the bit that got you triggered? Cause it's the sharpest criticism I found and if that draws out such vitriol from you, I suggest you get a thicker skin.

IE 222

lucernarian wrote: »

In fairness nothing, there's no (good) reason for people to reply like assholes or speak in a way most folks wouldn't dream of doing with colleagues, customers, acquaintances or even strangers.

I think the salient part of the question is obvious. Why would a barrier need be closed for 3 mins before a train arrives while in the Netherlands I observed it closed for 90 seconds on a track that had a 100kph speed limit? Like, it's not a rhetorical question, there must be specific reasons for why this happens especially at the likes of Sydney Parade.

Was there a station beside the crossing?
Was there another crossing within 1km both sides of it?
How busy was the crossing with non rail traffic?
Did the line run a mixed fleet of trains i.e electric and diesel?

For a southbound train at Sydney Parade the crossing wouldn't be down for much more than a min. It's only if a northbound train was going to enter the block before the gate reopening that they remain closed.

Gates must be opened for a min of 9 seconds otherwise they must remain down. This is how some trains are brought to a halt.

trellheim

I'm not getting into blocks and overlaps

Id like to ask a slightly different question

The D&KR has been running for 185 years and these LC's have been in place for a very long time

was there not pedestrian overbridges at these locations before or were they removed for electrification or has it always been this way

GerardKeating

trellheim wrote: »

I'm not getting into blocks and overlaps

Id like to ask a slightly different question

The D&KR has been running for 185 years and these LC's have been in place for a very long time

was there not pedestrian overbridges at these locations before or were they removed for electrification or has it always been this way

Pre-electrification, there was a "Pedestrian Overbridge" at Lansdowne Road Station, but i think it could be only be access from the platforms, it was replaced with an underpass, none of the other crossing ever had any other means of crossing the track. The is another underpass on the foot path along the River.

cdaly_

GerardKeating wrote: »

Pre-electrification, there was a "Pedestrian Overbridge" at Lansdowne Road Station, but i think it could be only be access from the platforms, it was replaced with an underpass, none of the other crossing ever had any other means of crossing the track. The is another underpass on the foot path along the River.

There was one crossing (since closed) at the West Pier Dun Laoghaire. The crossing was a request one, only opened when a vehicle wished to cross. Alongside this was a pedestrian gate which was normally open and only locked when one of the relatively few trains passed.

Sam Russell

GerardKeating wrote: »

Pre-electrification, there was a "Pedestrian Overbridge" at Lansdowne Road Station, but i think it could be only be access from the platforms, it was replaced with an underpass, none of the other crossing ever had any other means of crossing the track. The is another underpass on the foot path along the River.

There has a always been a pedestrian bridge at Sydney Parade accessible from the station. The Southbound platform could only be accessed by that bridge, be but in recent years, a pedestrian access has been built for southbound passengers. Furthermore, the old cast iron pedestrian bridge, which was clad in nasty iron sheeting, has been replaced by a very nice one. However, it is also only accessible from the platform.

Just to be clear, the SB trains cause the gates to close about 2 min before they arrive, and the gate opens straight after the train clears the gates. The NB trains trigger that gates about 3 mins before they arrive at the platform, where a stopping train will wait for a min or two. The gate opens when the train has cleared the gates and travelled a few hundred metres. Trains in both directions run on single yellow lights because the are gates in both directions.

If the Merrion Gates project was completed, it would not be a problem.

blobert

IE 222 wrote: »

I don't get why your so determined to challenge this.

Couple of reasons. Mainly from a selfish personal perspective, I'm spending 10-15+ minutes standing at these barriers every day watching them go down several minutes before a train rolls by at <20kmph. Yesterday I was stuck for over 15 minutes driving 200m with a screaming baby in the car beside me trying to get home. I'm planning to live where I live for rest of my life, those minutes will quickly add up to hours and days of life wasted. There's thousands of other people stuck at these barriers every day also so I'm sure there's lots of other people negative affected by it also.

Also from a practical point of view, I like solving problems and improving things and in my businesses have managed to improve a lot of things that were initially described as "can't be improved/just the way it is etc" so I like a challenge.

With the greatest respect to those with far superior knowledge of how this stuff works and who have posted to say it can't be done, I'd be absolutely amazed if it's not possible to improve the situation in some meaningful way from what it is at the moment. Now obviously the real question is how hard that is to do and how expensive. I think if there's a relatively simple solution that's far cheaper than building bridges then that's worth trying.

Just to sum up where I am with this at the moment:

(1) I'm hoping someone can very simply explain how the system for the barriers works at the moment. As per comments previously it seems to lower when a train hits a predetermined point on the track maybe 1.3-1.5km from the crossing. Where this is placed is determined by calculating how long it could take for the fastest train going at the line speed limit would take to reach the junction. Based on Wikipedia (as per my last comment) this seems quite an outdated system.

Does this sound correct?

(2) The line speed limit is currently set to 40mph/65kmph, this means the point that starts the barriers dropping has to be quite far from the junction to allow for the sceanior of a 40mph train. But the reality is that the trains traveling on this 2.5km stretch of track do not travel at anything like this speed, a lot of the time they are literally crawling along it. This is why there is a massive gap between the barriers going down and the train arriving, because it's configured for trains going 2-3 time faster than they do in reality.

(3) Therefore if you decrease the line speed limit to somthing like 30kmph you can move the point that starts the junction closing much closer to the junction itself, as now the fastest train will need less than <1/2 the stopping distance of this hypothetical 40mph train it's currently set for. Lowering the speed limit does not affect any trains as they are all going at a much lower speed anyway so passengers are not affected.

(4) Now the junction barriers don't start to close till the trains are much closer to the junction, so instead of closing 2.5-3 mins before the train arrives they might close 1 to 1.5mins. This still allows for the trains to safely stop if needs be in an emergency and roughly halves the length of time that the barriers are down without negatively affecting passengers and while making a massive improvement to traffic in the area.

If anyone that works at Irish Rail or has a good idea of how the current system works would give their comments on the above summary I'd appreciate it.

Thanks!

goingnowhere

Line speed limit is 100kph and has been for 35 years and trains passing through Merrion Gates assuming they get clear signals (as is the design) should be at above 90kph)

The rules on the DART are based on
1. Level crossing must be CCTV inspected and are interlocked with the signaling system
2. Full overlap protection is provided, so if gates are open, train is halted 200m from gates

Elsewhere in the world (where the instances of level crossing accidents are much greater) the gates are timed to drop and be down 30 seconds before a train passes based on the fastest train


For Merrion Gates the logic is

Depart Blackrock, train gets a yellow signal which enforces a 50kph limit before Booterstown
Loss of 30 seconds due the enforced speed limit due signals protecting Merrion Gates.
Stops in Booterstown with a red signal.
Doors open
Merrion Gates are requested based on a timer
Sydney Parade gates requested based on a timer
Gates close and are confirmed closed by CCTV
Signal clears to Yellow, next signals are Red (BN33), Red (BN31)
Driver moves off
Sydney Parade gates are confirmed closed by CCTV
Signal clears to Green, next signals are Double Yellow (90kph), Yellow (50kph) this gives a profile where the permitted speed is greater than the braking curve
DART even if it has past the first signal will pick up that the signal was retrospectively Green and give the driver 100kph
Train arrives Sydney Parade with gates down and a yellow signal, the yellow signal is because Sandymount gates are not down
Timer runs to call Sandymount gates
Sandymount gates are confirmed closed by CCTV
Train departs, the signal at Sydney Parade will move to double yellow (90kph)
Next signal is yellow as Serpentine Ave gates are not closed, these trigger


There is an upgrade to the DART ATP system coming which should allow DART trains to travel much faster when faced with restrictive signals, giving a braking curve based on the red signal ignoring all others instead of the current static speed control system which was very clever for 1984 but is prehistoric by current standards but still exceptionally reliable

CatInABox

blobert wrote: »

Couple of reasons. Mainly from a selfish personal perspective, I'm spending 10-15+ minutes standing at these barriers every day watching them go down several minutes before a train rolls by at <20kmph. Yesterday I was stuck for over 15 minutes driving 200m with a screaming baby in the car beside me trying to get home. I'm planning to live where I live for rest of my life, those minutes will quickly add up to hours and days of life wasted. There's thousands of other people stuck at these barriers every day also so I'm sure there's lots of other people negative affected by it also.

If this is true, the best thing that you can do is contact your local representatives and push them to progress the Merrion Gates project. Right now, they're only hearing from locals opposed to the project.

As to Irish Rail reducing the time the gates are closed, it's not going to happen. They're a pretty conservative company, and won't put the lives of hundreds of people in danger just to enable a tiny increase in the number of cars getting through the gates.