From: rcp27g@gmail.com
On 2015-02-20 14:59:23 +0000, Adam H. Kerman said:
> bob wrote:
>> On 2015-02-17 16:38:27 +0000, Adam H. Kerman said:
>>> rcp27g@gmail.com wrote:
>>>> On Monday, 16 February 2015 16:25:47 UTC+1, Adam H. Kerman wrote:
>>>>> bob wrote:
>>>>>> On 2015-02-13 20:23:01 +0000, Marc Van Dyck said:
>>>>>>> rcp27g@gmail.com explained on 13-02-15 :
>
>>>>>>>> or putting in positive singalling control on others (ie where the
>>>>>>>> crossing is protected by railway signals that aren't cleared for the
>>>>>>>> train until the barriers are down and the crossing positively checked
>>>>>>>> to be clear).
>
>>>>>>> This is perfectly feasable but requires to order the gates to go down
>>>>>>> at a distance that is longer than the braking distance of the train.
>>>>>>> This means there will be a long delay between the gate going down and
>>>>>>> the train actually passing the grade crossing.
>
>>>>>> Indeed, this is the case. It is less convenient but allows for
>>>>>> positive safety.
>
>>>>>>> As it has been mentioned,
>>>>>>> motorists are unpatient creatures; if the delay is too long, people
>>>>>>> think the gates are faulty and start turning around them. You might end
>>>>>>> up this way with a grade crossing that is inherently less safe, because
>>>>>>> of human nature...
>
>>>>>> Solved by making the barriers block the whole road. As the crossing is
>>>>>> positively checked to ensure the barriers are down and the crossing is
>>>>>> clear before clearing the signals for the trains, the issue of cars
>>>>>> being trapped within the crossing is avoided.
>
>>>>> Clearing level crossings several minutes before the train arrives
mitigates
>>>>> against non-existant risk, and it's quite labor intensive. How is the
>>>>> cost of delay justified? How is the personnel cost justified?
>
>>>> This "non-existant risk" just killed 6 people.
>
>>> You know, I really can't stand people on Usenet who can't debate,
>>> and therefore find it necessary to set up a straw man.
>
>> Pot, meet kettle.
>
> Well, no, I didn't set up a straw man, so your PKB accusation is
> inappropriate.
>
>>> She didn't violate the grade crossing minutes before the train arrived, but
>>> within the last 15 seconds. She had a minor intrusion at about 15 seconds,
>>> then at about 5 seconds, pulled deliberately into the path of the oncoming
>>> train.
>
>> You are contending that people will violate a crossing regardless of
>> the state of barriers across the roadway blocking access to the
>> crossing. I contend this is not the case.
>
> Drivers drive around lowered crossing gates. There's a famous video of
> a driver who drove around lowered crossing gates in a situation in which
> video cameras were placed at a newly-designed grade crossing with major
> safety improvement. A center barrier had been erected for the last 40 feet
> of the highway approaching the grade crossing, and the lowered gate
completely
> blocked that side of the highway. A motorist made the decision to drive
> onto the wrong side of the highway to drive around the lowered gates.
Strawman. I have explicitly and specifically stated that the crossing
type concerned here has *full* barriers across the whole roadway at
both sides of the railway. You are describing an incident of a driver
violating a crossing with half barriers, *not* blocking the roadway
that a driver violated.
> You cannot contend that a safety system can be placed at a grade crossing
> that no driver will violate.
I contend that drivers who are willing to drive around crossings, as a
calculated risk, will not be willing to drive through two physical
barriers, a process which will almost certainly case actual damage to
their car in the process.
>> In the collision in question here, the barrier came down *on top of*
>> the vehicle. That means the vehicle was *already* inside the crossing
>> (as defined by the area bounded by the road barriers) *before* the
>> barriers came down.
>
> It means that she violated the grade crossing, ignoring the flashers and
> bells AND the gate that was in the process of being lowered. If anything,
> a gate being lowered moves and truly catches the driver's eye, so that
> actually adds a bit of safety.
I haven't heard an account of the events leading up to the events in
this specific crash about how the driver ended up under the barrier,
and as people have died in this crash, I don't want to enter into
speculation.
> A crossing gate isn't a genuine barrier as they are designed to be
> flexible and to break readily so that vehicles are NEVER trapped. The
> main purpose of the crossing gate is to put additional flashers at
> the driver's eye level, at least when it's lowered.
In a crossing where the trains are controlled in a way that prevents a
collision in the event of a car or other road users becomes trapped on
the crossing, there is no safety hazard associated with vehicles
becoming trapped on the crossing: the train stops, the barriers are
raised, and the vehicle escapes. If there is no need to allow trapped
vehicles to break through, the barriers can be made much more robust
(and obviously so).
>> I would suggest that, while some drivers will enter crossings with the
>> barriers up even if the lights/sound warnigns are active, and will drive
>> around partial barriers (plenty of youtube videos show this taking place),
>> they are far far less likely to drive *through* a barrier that is blocking
>> the road.
>
> That's nice, but you're backing off your earlier contention that drivers
> won't violate the grade crossing given the state of barriers across
> the roadway. So you still think some drivers will violate the grade crossing.
It has never been my contention that drivers will not attempt to
violate a crossing in which the barriers are not yet fully down across
the whole width of the roadway. My contention is that in a crossing
where the trains signals protect the crossing, in the event that the
crossing is violated, the result of the violation will not be a
collision.
>>> The system you advocated addresses a period of minutes before the
>>> train arrives in which there really isn't any danger of collision.
>
>> The difference between the crossing types I have described is not down
>> to the method used to keep cars off the crossing, but the method used
>> to keep *trains* off the crossing. In the crossing involved in this
>> collision, there is *no* method to stop trains from crossing.
>
> Now you're trying to imply that trains can stop on a dime. Lovely.
>
> As I've already explained about PTC grade crossings just recently installed
> between Chicago and St. Louis, they have to be active many minutes before
> the train gets there so that the train can be thrown into emergency and,
> even then, it'll reduce speed down to 15 mph. Still addressing the issue
> of grade crossing violations that occur minutes before the train gets
> there, and not within the last 10 seconds as with the situation that
> we are discussing. It addresses a truck that stalled within the grade
> crossing minutes before the train gets there, nothing else.
Another straw man. I am not describing a crossing where the failure of
the railway signalling to clear for the train still results in the
train passing the crossing at 15 mph. I am describing a crossing
where, in the event of the crossing not being found to be clear in the
intended manner, the train will be brought to a stop, with a normal
service brake (not emergency), with distance to spare before the
crossing.
> The rest snipped unread. You just don't know what you're talking about.
Well the bit you snipped addressed your points. If you not to actually
read what I wrote but create strawman arguments then there is no point
is pursuing this discussion.
Robin
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