Railroad grade crossing signals. If I am approaching a grade crossing and the signals are not working, is it almost certain that it’s safe to cross?
I watched a youtube video of a train splitting an 19-wheeler in half. In this case, the crossing signals (both lights and gates) were not working. What (if any) backup procedures are there for these signals? For example, is there a battery backup in case of power failure? What happens if some saboteur destroys the sensor that detects the presence of a train? Can the signals themselves start flashing if a fault is detected? Do the signals themselves send some notification back to headquarters if they detect a fault? Are there other things that can go wrong??? Does the train operator have any way of detecting whether a crossing signal is inoperative?
As a side note, I was on a train a few years ago when the train stopped between stations. It then proceeded forward at 5-10 MPH for a few minutes before resuming normal speed. I asked the conductor why we stopped. In this case, the train knew that a grade crossing signals were inoperative, but they knew that before the journey started.
If you, as a driver, are approaching a grade crossing, how would you know that a signal wasn’t working, versus the idea that there simply isn’t a train approaching the intersection? There’s a reason certain vehicles always make a full stop and look both ways before crossing any train tracks. You can’t be absolutely sure, so it’s safest to assume the worst before going through.
As for train operators knowing a signal isn’t working, I am under the impression that signal problems pop up for those in charge of monitoring the system. I used to ride LA’s Metrolink daily for a decade, and it was not infrequent that we’d be told of a signal issue. We’d have to stop as we got near the intersection and then wait while the conductor disembarked and manually triggered the cross-arms so that the train could safely pass through.
Trains blow their horns as they approach the grade crossings … very loud … so to be even more safe, always listen as you come to the crossing … our local school district requires their school buses to come to a complete stop at all railroad crossings … to listen and look … some might say that’s going a little too far … but just look at what happened to that “19-wheeler” [sic] …
I (vaguely) know a deaf woman who died because the crossing signal wasn’t working and she did not hear a train coming. So, listen if you can, but we can’t rely on that.
Not to mention, the engineer might forget to blow the whistle, and trains aren’t very loud all by themselves anymore. So it’s not just the deaf who need to consider that they might not hear a train coming.
Some trains go through areas where the local people would rather the safety of the whistle be silenced than have to listen to a train whistle all day. So there are plenty of crossings where a train isn’t going to whistle.
I am a train nut and I’ve never seen a grade crossing not working while a train was in it. I have seen plenty flashing (with the arms down if applicable) with no train in the vicinity and once, an arm being held up by a cop while he waited for the railroad’s fix-it team to arrive.
The ones with arms have the arms weighted so it takes power to hold them up. If the power (and the battery backup) fails, they fall slowly down to horizontal (no lights, of course). Railroads have a fail-safe philosophy in that if a signal fails, it should fail to the most restrictive indication; semaphore signals were also arranged so they had to be held clear by power and failure would make them move to a more restrictive aspect. One reason lower quadrant signals were replaced by upper quadrant was because there were a few instances where accumulated snow or ice had forced the blade (even with power on) to the clear aspect.
The part that detects the train – both for grade crossings and the railroad signals – are the rails themselves. There are insulators to keep them isolated from the ground and each other and a train on them shunts one rail to the other, making a relay deenergize. It’s hard to see how that part could be vandalized; a better target would be to break into the relay shed.
On the sides of the flashers there is a small – about an inch – port with a sunshade on the top. They show a white light to the side when the light in the flasher is on. I’d always assumed they were so the crew could witness that the crossing signal was working if there was an incident.
Can you still find that Youtube video? With all the above I’d find it hard to believe it happened that way. I’ve seen plenty of them smashing into a semi-trailer but usually one stalled on the tracks or driving onto them.
I just love when GQ gets answers that aren’t based in fact, but just expression of opinions. :rolleyes:
Here is what California’s DMV says in its driver handbook about railroad crossings. Notice the important language: “Look in both directions and listen for trains. … Expect a train on any track, at any time, traveling in either direction.” The fact that a crossing is gate guarded is not a guarantee that the gates will always work; you should always approach a crossing with an eye towards determining if a train is approaching.
As for when trains need to blow horns, the basic rule is governed by 49 CFR 222: summarized here. Notice that state and local governments can designate “quiet zones” as explained at length by the pdf available at the following link: How to create a quiet zone. Integral to such zones are the use of Supplementary Safety Measures, which are described here: 49 CFR Appendix A to Part 222. Notice that, to be compliant as a gate and signal system, the system must have power loss indication. When that happens, the train will know to blow its horn because the signal is not properly working.
Thanks to Desert Dog for posting valuable information, too.
I read somewhere that if your vehicle is stuck on the tracks and you want to prevent a collision with an oncoming train, attaching jumper cables to the two rails (in short, causing a short between them) will cause a red signal for the train. Any truth to that?
I think all you will accomplish with that is dropping the crossing gates, i dont know that it will give a red light stop signal.
I think the best way to avoid a collision is to get the hell out of your car and walk a safe distance away while calling 911, so they can alert the railroad among other things
On the question of does the train operator know the signals are working:
On the city light rail I used to ride there were white lights installed as part of the crossing gates & red light signals. The white lights aimed along the tracks. Once the gates were down and the red stoplights were flashing for cars the white lights came on to signal the train operator that the crossing had been secured. If the white lights didn’t come on the train operator would aggressively brake to a stop before arriving at the crossing.
IME these features are *not *common on mainline railroads. They may be retrofitted in some areas. In many cases the train is already committed by inertia and speed to entering the crossing before the gates are triggered. E.g. A high speed freight train takes 1 mile to stop. Gates & red lights trigger when train is 1/4 mile away and should be fully down when train is 1/8 mile away. If gates fail completely and operator knows it at the 1/8 mile point he/she is still committed to roll through the intersection by 7/8ths of a mile.
We could fix that if the road users were willing to sit at a set of closed gates for an extra minute or 3 while waiting for the train to travel the whole mile to the crossing. But they’re not.
Lots of shortcuts versus maximum attainable safety are taken every day by everyone. It works well enough for society as a whole because signaling systems are reliable enough. If you draw the short straw some day take comfort that all the time that you and all the other drivers have saved over the years is more than enough to balance the rest of the life you won’t get to have.
If you read the info below the video, because of the weather the gates were down even with no train and a railroad employee “fixed” it. When you think you’ve got a fool-proof system, somebody invents a better fool.
If the track has block signals doing so would change the signal to red. Problem is the block signals on either side of the crossing can be miles away and a train could have passed the one for its direction minutes before you shunted the track. In other words, don’t count on it absolutely.
When I was in Flagstaff a couple years ago I’d noticed a signal that was a flat panel with a big, flashing, LED X. It took me a little digging to figure out what BNSF meant by it; turned out that if the signal was flashing like that, the engineer did not have to blow for the next crossing.
When Burning Man is being held, there are three hot springs in the vicinity that are closed to the public for the duration. One of them is close to Black Rock City, just on the other side of the UP (ex-Western Pacific) tracks on the east side of the playa. People are posted at all three to enforce the closure and are swapped out three times a day. I’m part of the team that drives the volunteers out and back and the strict instructions for the crossing are to stop the van, roll down the windows on either side, and wait for fifteen seconds before proceeding across the tracks. When somebody asked why before the event, I posted this video of a staged crash in New Zealand. I picked it because nobody got hurt and, being staged, there are lots of nifty camera angles. Notice how long it takes the train to stop after the impact.
I read some years ago about predictive grade crossing signals that trigger 30 seconds before arrival, regardless of train speed. I guess these are not installed on every grade crossing with signals/gates?
A google search on “railroad jumper cables” turned up a lot of results, including a SDMB thread from 16 years ago. It looks like it might be possible. No relation to any nearby grade crossing, the theory is that it closes a circuit that indicates a train is present on that section of track, and the system then lights up a red signal to any approaching train that they should not enter that section of track. The problem is that if a real train has already entered that section of track, then they’ve already activated (and passed) the red signal. IOW, jumpering the track might successfully signal an approaching train to stop, which could save your car - but you should still get the hell out of the car and call 911 (and, optionally, take everything of value out of the car ASAP).
So much of the US railway infrastructure is ancient legacy stuff that its a good bet there’s still thousands of installations of 1950s stuff out there.
Even 30 second predictive signals won’t prevent problems if it takes 2 minutes for the train to stop. If, for example, it does take the train 2 minutes to stop then signals must be down, and known to the engineer to be down at least 2 minutes plus a few seconds before the train arrives.
The problem is car drivers are antsy. Every second the gates are down before the train arrives is another second where the most impatient driver in the queue is getting closer to his “To heck with it, there’s no train! I’m going around these stupid malfunctioning gates!!#$#!”. Just as the train finally does arrive.
There’s no squaring that circle with total safety.
Indeed, the intent of grade crossing signals is not to give the engineer enough time to stop the train - it’s solely to give motorists and pedestrians enough time to get out of the way of the non-stopping train; sorry for any confusion, I didn’t mean to suggest otherwise.
Heee Yah! You gave explicit advice on what to do, though. I’d only add if the train is right there, run towards it so the debris from your former car doesn’t hit you.
If only. Try 80 year-old in a few spots. The first segment even has a wig-wag crossing signal and an upper-quadrant semaphore at the same location.
They are getting rare, though. Last time I checked, a restored wig-wag signal cost about $5,000, unrestored (i.e. junk) was two or three grand.
