When are Gates Designed Go Down at a Crossing?

[gisa]

Hi All,


I'm not sure if this is in the right sub-thread. If it is in the wrong place, I'm totally okay if a mod wants to move it. This query I have concerns North American Railroads. Kind of a tough question for someone working in the railroad industry...

I'm working (and may forever be working) on a prototypical route. I'm setting up some crossings and am using Boat's wonderful ATLS system. Everything is working the way I want it to. I have my roads connected, gates and bells hooked up and it's great; however, I've come across a problem and was looking for input.

My problem: I'm putting down the triggers for when the gates should come down/bells go off, but I have no idea where to place them. What is the generally accepted distance/time needed for a train going at x speed. What about a train going at y speed or z speed? Or a train that has a heavier load (or is that even relevant?). In a perfect world, the gates would come down with the worst case scenario in mind to give generous stopping time in case of a problem at a crossing, but we know that this unfortunately does not happen. So...

I was wondering if there is a chart, or a website with more information on distances and timings in terms of when a gate should come down/bells go off as a train approaches a crossing. The time is really scary, based on some videos I've seen on youtube, but I have no idea where to place the triggers and I'd like to be realistic within reason.

(I'd love to err on the safe side, but I think the drivers in my route would be pretty angry with my plans. :hehe: )

I'd like to put these triggers at a generally correct area, and since trains travel at various speeds, a chart or website with a formula or information would be really handy. I tried a search on google but had no luck.

As well, in real life, are there ways to compensate for trains going at various speeds? In the area I am modelling, there are local and express passenger trains plus freight trains. The crossing I'm currently working on is right next to a local passenger station. I guess I have no choice but to opt for safety although I'm sure the locals will learn to hate the commuter train! I assume there is no way to use the ATLS triggers to factor different trains approaching at different speeds?

I wonder how that works in real life, if at all. As far as I know, a train goes over a circuit at a specific point on the tracks, which sends a message to a relay box to tell the crossing to go down/be active.

Thoughts? Links? Formulas?

:wave:

Gisa ^^

 

[jnjkerbin]

I would guess that it would be dependant on the type of signalling. I think a signal normally remains at danger (red) unless the gates in front of it are closed to traffic. There fore if you are using 3 aspect signalling and you will have the train not stopping before the crossing, you would ideally have it so that the driver does not get yellow (caution) aspect unless there is a station immediately before the level crossing which the train will be stopping at for sometime.

I'm not sure if this is how they actually do it but this is the basis I go on. In this way, with 4 aspect signalling as is widespread here in the uk It would be something like this:

Gates open -R-------Y----------YY----------G----------Train

Gates close -G-------G----------G---Train---R

YY Meaning advanced caution.

Not sure though....
Joe

 

[torino72]

Placement of Sensors at RR Grade Crossings

Here is a link to a PDF that might be helpful.
http://www.techtransfer.berkeley.edu/railroad06downloads/nizam_macdonald.pdf

I think the answer is that it depends on a number of conditions, such as track speed limits, actual train speed, track classification, etc. so there is no "one size fits all" for where sensors should be placed.

I think BNSF50 once said (and I may be quoating the incorrect source here) that his crossings were designed for trains traveling at 40 MPH. That is why trains traveling at 60 MPH were reaching the crossing before the gates were fully down. The document referenced above discusses how long the gates should be fully down before the train reaches the grade crossing.

 

[pfx]

The way I set them up is with 2 triggers. One that will only react to high speed trains, the other to everything else but both set at a distance from the crossing that will ensure the gates are closed for the same time.

I'm not sure what the gate times are (I've seen some US ones that don't close until the train is at the crossing and has stopped to allow gates to close) but I think it is at least a minute before the train hits the crossing in the UK. Someone will know for sure.

 

[FLWBStrainman]

As others have said, it depends on several factors, chiefly train speed. It varies. I'm pretty sure the bare MINIMUM in most cases is that the lights must be activated at least 15 seconds before the train enters the crossing, and all gates must be in full horizontal position for at least 5 seconds before the train enters the crossing, but that is really pushing it. Ideally, there should probably be at least 20 to 25 seconds of warning time I would think. I seem to remember setting my activation triggers about 1,350 feet back in 30-45 speed zones, and I thought that usually timed out about right. If the crossing is activated too soon, though, cars are more likely to get impatient and drive through. Less likely to happen in Trainz though

 

[rrfoose]

I was just wondering this same question today Gisa! Like PFX said, you can set certain triggers for trains of different priorities. I'm still learning to use the ATLS system (just started this week, actually), but I'd ASSUME that you could use the 4-trigger method with more than 4 triggers...say 6? That'd give you, in each direction, the inbound trigger for the Priority 1 train (aka the passenger trains, moving at 70mph), a second inbound trigger for trains of priority 2 & 3 (freights and locals moving at 50 & 30mph respectively), and then the outbound. Or maybe try 8 triggers with one for each priority/speed category. That'd be a lot of work to set every train's priority though. And I'm guessing in the real world, there is only one trigger - set for the highest speed train. And if the train isn't going that fast, people just have to wait. One "option" we don't have though is for the gates to go back up if the train doesn't reach the crossing in a prescribed amount of time (often used in locations where switching is occurring on one side of the crossing so that gates won't be down ALL of the time). But I too am looking for an answer on the recommended amount of time before a train hits that the gates should start going down.

 

[FLWBStrainman]

Some of the newer crossings on class 1 railroads actually calculate the speed of the train and its from the crossing, and activate the signals accordingly. Some railroads use technology that allows the engineer/conductor to manually activate the signals via radio control. But the vast majority of crossings are activated by a single entrance circuit that trips when a locomotive/car passes over it. In cases where the train is only going 5 mph, that can be a long wait!

Here's a tip: if you have two or more crossings relatively close to each other, you might want to consider grouping them to the same trigger(s), so they activate at the same time. This IS prototypical in some cases, and I find it's easier than having to jack around with multiple activation triggers when you've got two roads 200 feet from each other. The only thing I haven't figured out is how to make them clear separately.

And remember to start blowing your horn at least 15 seconds before you enter your crossings!

 

[gisa]

Thank you everyone for your replies!

Here is a link to a PDF that might be helpful.
http://www.techtransfer.berkeley.edu/railroad06downloads/nizam_macdonald.pdf

I think the answer is that it depends on a number of conditions, such as track speed limits, actual train speed, track classification, etc. so there is no "one size fits all" for where sensors should be placed...

Great pdf! It was a neat read as a trainzer. I found this page the most useful to me:

The way I set them up is with 2 triggers. One that will only react to high speed trains, the other to everything else but both set at a distance from the crossing that will ensure the gates are closed for the same time...

I didn't know this was possible! I'll try it out and see what I can do.

As others have said, it depends on several factors, chiefly train speed. It varies. I'm pretty sure the bare MINIMUM in most cases is that the lights must be activated at least 15 seconds before the train enters the crossing, and all gates must be in full horizontal position for at least 5 seconds before the train enters the crossing, but that is really pushing it. Ideally, there should probably be at least 20 to 25 seconds of warning time I would think. I seem to remember setting my activation triggers about 1,350 feet back in 30-45 speed zones, and I thought that usually timed out about right. If the crossing is activated too soon, though, cars are more likely to get impatient and drive through. Less likely to happen in Trainz though

See the image I posted above.

I was just wondering this same question today Gisa! Like PFX said, you can set certain triggers for trains of different priorities. I'm still learning to use the ATLS system (just started this week, actually), but I'd ASSUME that you could use the 4-trigger method with more than 4 triggers...say 6? That'd give you, in each direction, the inbound trigger for the Priority 1 train (aka the passenger trains, moving at 70mph), a second inbound trigger for trains of priority 2 & 3 (freights and locals moving at 50 & 30mph respectively), and then the outbound. Or maybe try 8 triggers with one for each priority/speed category. That'd be a lot of work to set every train's priority though. And I'm guessing in the real world, there is only one trigger - set for the highest speed train. And if the train isn't going that fast, people just have to wait. One "option" we don't have though is for the gates to go back up if the train doesn't reach the crossing in a prescribed amount of time (often used in locations where switching is occurring on one side of the crossing so that gates won't be down ALL of the time). But I too am looking for an answer on the recommended amount of time before a train hits that the gates should start going down.

Glad someone else wanted to know the answer to this one as well. You are right, it's a lot of work to set up a lot of triggers for multiple crossings. We'll see...

Some of the newer crossings on class 1 railroads actually calculate the speed of the train and its from the crossing, and activate the signals accordingly. Some railroads use technology that allows the engineer/conductor to manually activate the signals via radio control. But the vast majority of crossings are activated by a single entrance circuit that trips when a locomotive/car passes over it. In cases where the train is only going 5 mph, that can be a long wait!

Here's a tip: if you have two or more crossings relatively close to each other, you might want to consider grouping them to the same trigger(s), so they activate at the same time. This IS prototypical in some cases, and I find it's easier than having to jack around with multiple activation triggers when you've got two roads 200 feet from each other. The only thing I haven't figured out is how to make them clear separately.

And remember to start blowing your horn at least 15 seconds before you enter your crossings!

Excellent tip. There are some crossings in a relatively close area so this will save time and effort.

Thanks again for your input everyone.

:wave:

Gisa ^^

 

[captainkman]

Here I go!

Q. When are gates designed to go down at a crossing?

A. When a train comes, of course!

Serious now:

Like others said, experiment with different speeds and distances. Find what suits you and apply it.

 

[rrfoose]

I also looked through that briefing above - very informative! Using that info I set up my triggers for 30 seconds based on max speed limit. This produced, what I thought, was very prototypical timing. However, if I want to use a static camera at a crossing and watch the gates go down and the train approach, the distance is "too far" between the train and the crossing when you have a train moving 50 or 60 mph. So I moved the interval to 20 seconds - it gives me what I consider a good compromise between realistic and trainz entertainment!

 

[HSSRAIL]

I would like to answer this question from a historical perspective.

Currently there is technology that activates crossing protection for 20 seconds prior to arrival of a train at a crossing regardless of speed this is called CWD
Constant Warning Device.

Historically Crossing devices were set to activate for the highest speed trains were allowed. The amount of time was variable based on train speed they did not adjust. The next development was two speed warning gates would activate sooner for trains going a set faster speed and later for trains going a low speed look for instructions in employee timetable that say "should not exceed this speed until crossing is occupied" as a guide that this system is in use.

The first crossing detection systems could not detect for trainsoperating in both directions they would only work for one direction. Railroads that had this situation had a notice in their rule books trains operating against current of traffic must stop and flag highway grade crossings.

Howard