Railfan Technology > crossing gate/signal question

 If a crossing gate is not energized, is it always set up to drop to a horizontal position? I thought that I  read this somewhere and saw a video in which a guy was doing maintenance on his backyard gate. When he de-energized the gate, it dropped to horizontal. 

Also, on occasion crossing signals do not function when a train approaches. Presumably there would be electricity to the gate but a malfunction in the detection circuit. 

Thanks for any explanations.

colehour Wrote:
-------------------------------------------------------
>  If a crossing gate is not energized, is it
> always set up to drop to a horizontal position? I
> thought that I  read this somewhere and saw a
> video in which a guy was doing maintenance on his
> backyard gate. When he de-energized the gate, it
> dropped to horizontal. 
>
> Also, on occasion crossing signals do not function
> when a train approaches. Presumably there would be
> electricity to the gate but a malfunction in the
> detection circuit. 
>
> Thanks for any explanations.

I'll take a shot at answering it. Some 40 years ago I was a RR "helper" on an electrical gang that installed and maintained Grade X-ing signals.
The power to run the things was sourced off the city/county Lines. But of course, that power sometimes fails so the Railroads have used backup
power sources to allow the Gates to do their thing. In my era- that was wet cell batteries, that sat in small vaults in the ground, adjacent to the X-ing.
These wet cell batteries, similar to the ones in our cars and trucks needed quarterly maintenance or whenever we could get to them; top off the H20,
check the connections and perform a test we called "shunting the rails." We would attach a special wire with pointed clamps to each Rail- and let the
Gates run through a cycle or two. The motorists would stop, curiously look back and forth for the approaching "Train."

To your question now Jerry. Power drops, wet sand between the rails, mechanical issues, etc.  can cause Grade X-ing malfunctions but fortunately they work really, really well. We all know what legal complications can arise in this area with the Gates not coming down. But if the main land power, battery backups or now solar power systems were to have an absolute Fail- the Gates would just stay in the position they were in when the power had that fail. Not drop to horizontal, as an engineered feature. They just wouldn't move.And it's time to call the Signal Maintainer.
Hope that helps. If anyone here has more current info than me- thanks in advance.

Thanks for the information, OldPorter. I can see that a gate that dropped when the power went out would be a problem since it would be blocking a grade crossing when there was no train. Of course, that occasionally happens even if there is power to the system. 

I am fascinated by the sophistication of today's track circuits, particularly with motion and speed detection. I am old enough to remember crossing watchmen at some crossings in my hometown! Things have certain changed...

We have noticed when the power is out, the gates do stay up, however, the signal cabinet will have a really bright strobe light.  I guess to alert the train crews of a "issue".

Christi

SouthWest RailCams
CA, NM, CO, TX, AZ
https://SouthWestRailCams.com



Edited 1 time(s). Last edit at 04/29/21 11:35 by RailFanAZ.

If the gates would come down when there was no power, there would be no flashing lights or warning bell to alert motorists of the obstruction. That would be more of a liability than a fail-safe. Good chance a motorist runs into the gate, breaks it, and file a claim for damages to his vehicle against the railroad.

Arved Grass
Fleming Island, FL

Arved Wrote:
-------------------------------------------------------
> If the gates would come down when there was no
> power, there would be no flashing lights or
> warning bell to alert motorists of the
> obstruction. That would be more of a liability
> than a fail-safe. Good chance a motorist runs into
> the gate, breaks it, and file a claim for damages
> to his vehicle against the railroad.

Yes, I mentioned the problem of a gate dropping when the power was out in a previous post. 

 

Commercial power runs battery chargers which keeps banks of batteries charged. The signal system as well as crossing equipment runs on low voltage dc. In the event of a commercial power failure, the strobe on the equipment house will light off indicating a loss of power. This does a couple of things, 1-alerting a train crew to the failure in which they should or are required to notify the dispatcher, and 2, if a railroad employee sees such light flashing, notify the dispatcher. Now the signal desk gets a call and then they notify a maintainer. The desk also notfies the local power company to see if there is a reported outage in the area. Sometimes the circuit breaker will trip at the local site. These strobes are also on wayside signal houses. If the power is off long enough and there is a large amount of rail traffic, crossings may last only 10-12 hours. On lightly used branches or industrial tracks, they can last almost a month, then you get a call for gates down, no lights or bells, been there, done that. Under no circumstance do you want a gate to remain up when there is no power on it, that is a liability no one wants.

RailFanAZ Wrote:
-------------------------------------------------------
> We have noticed when the power is out, the gates
> do stay up, however, the signal cabinet will have
> a really bright strobe light.  I guess to alert
> the train crews of a "issue".
>
> Christi

SP4360 Wrote:
-------------------------------------------------------
> Commercial power runs battery chargers which keeps
> banks of batteries charged. The signal system as
> well as crossing equipment runs on low voltage dc.
> In the event of a commercial power failure, the
> strobe on the equipment house will light off
> indicating a loss of power. This does a couple of
> things, 1-alerting a train crew to the failure in
> which they should or are required to notify the
> dispatcher, and 2, if a railroad employee sees
> such light flashing, notify the dispatcher. Now
> the signal desk gets a call and then they notify a
> maintainer. The desk also notfies the local power
> company to see if there is a reported outage in
> the area. Sometimes the circuit breaker will trip
> at the local site. These strobes are also on
> wayside signal houses. If the power is off long
> enough and there is a large amount of rail
> traffic, crossings may last only 10-12 hours. On
> lightly used branches or industrial tracks, they
> can last almost a month, then you get a call for
> gates down, no lights or bells, been there, done
> that. Under no circumstance do you want a gate to
> remain up when there is no power on it, that is a
> liability no one wants.

So, if there is no power, either from the grid or the batteries, the gate will go horizontal. I suspect that does not happen very often. As I said in my original post, I saw a video of gate maintenance (in a guy's yard) that showed that when he de-energized the gate, it dropped to horizontal. I gues that is better than no warning at all, despite the potential problem of running into a gate that has no warning lights.

Perhaps the Monon's green light system was a good idea: when the green light is out, stop. It seems to be fail-safe but, of course, it requires people to pay attention.

Correct, when the commercial power is out and the batteries die, gates go down. Also, at signal locations, track indications appear on the dispatchers display, signals will drop to red and things slowly grind to a halt depending on the length of time the power is out. We had to haul around generators and charge batteries from location to location after the wildfires and I had my truck inverter hooked up to the sub panel supplying ac to power the chergers. 

colehour Wrote:
-------------------------------------------------------
> SP4360 Wrote:
> --------------------------------------------------
> -----
> > Commercial power runs battery chargers which
> keeps
> > banks of batteries charged. The signal system
> as
> > well as crossing equipment runs on low voltage
> dc.
> > In the event of a commercial power failure, the
> > strobe on the equipment house will light off
> > indicating a loss of power. This does a couple
> of
> > things, 1-alerting a train crew to the failure
> in
> > which they should or are required to notify the
> > dispatcher, and 2, if a railroad employee sees
> > such light flashing, notify the dispatcher. Now
> > the signal desk gets a call and then they notify
> a
> > maintainer. The desk also notfies the local
> power
> > company to see if there is a reported outage in
> > the area. Sometimes the circuit breaker will
> trip
> > at the local site. These strobes are also on
> > wayside signal houses. If the power is off long
> > enough and there is a large amount of rail
> > traffic, crossings may last only 10-12 hours.
> On
> > lightly used branches or industrial tracks,
> they
> > can last almost a month, then you get a call
> for
> > gates down, no lights or bells, been there,
> done
> > that. Under no circumstance do you want a gate
> to
> > remain up when there is no power on it, that is
> a
> > liability no one wants.
>
> So, if there is no power, either from the grid or
> the batteries, the gate will go horizontal. I
> suspect that does not happen very often. As I said
> in my original post, I saw a video of gate
> maintenance (in a guy's yard) that showed that
> when he de-energized the gate, it dropped to
> horizontal. I gues that is better than no warning
> at all, despite the potential problem of running
> into a gate that has no warning lights.
>
> Perhaps the Monon's green light system was a good
> idea: when the green light is out, stop. It seems
> to be fail-safe but, of course, it requires people
> to pay attention.

Far as I know, modern gates are designed to be lightweight and break-away, and cheaper to fix or replace than the old fabricated gates. Thus, when power failure causes gates to drop, traffic will go around them after looking for a train, or someone will drive through and pop the gate off the arm. In many cases, a maintainer will fix the problem before that occurs.