overhead grade crossing lights

[JonMyrlennBailey]

They look both pricey and fancy. Why do a few American crossings have this overhead framework but most don't?

 

[Forester1]

Interesting that your photo has those on a two-lane road. I was going to say they were more prevalent on four lane roads, but your photo shows that is not the only case.

 

[JonMyrlennBailey]

Interesting that your photo has those on a two-lane road. I was going to say they were more prevalent on four lane roads, but your photo shows that is not the only case.

Do those cost railroads about $5K each to install vs the simpler gates? Trainz content has these available for both two and four lane roads.

 

[AFdude06]

It could have to do with the amount of traffic. Here on the LOSSAN Corridor and branches off of it, gantry-type crossing signals (similar to what you posted a photo of) are used on higher traffic roads and almost exclusively in big cities like San Diego. For smaller crossings standard signals are used. For example, the LOSSAN runs through downtown San Diego, and crosses some smaller neighborhood roads. Even those use gantry signals, whereas in Oceanside small neighborhood roads generally have double sets of standard signals.
What I find interesting about your photo is that the gates seem too long for those lanes. Maybe they were repurposed?

Cheers

 

[JonMyrlennBailey]

It could have to do with the amount of traffic. Here on the LOSSAN Corridor and branches off of it, gantry-type crossing signals (similar to what you posted a photo of) are used on higher traffic roads and almost exclusively in big cities like San Diego. For smaller crossings standard signals are used. For example, the LOSSAN runs through downtown San Diego, and crosses some smaller neighborhood roads. Even those use gantry signals, whereas in Oceanside small neighborhood roads generally have double sets of standard signals.
What I find interesting about your photo is that the gates seem too long for those lanes. Maybe they were repurposed?

Cheers

I don't know. I just found that picture on Google at random as an example to show here. In America, most track crossings don't have such monstrosity of a structure. Those overhead signals might give some large trucks issues with overhead clearance. In Trainz Mojave Sub Division, there are only about 3 out of 17 total active crossings with such overhead structure. My drivable MFM double decker cattle trailer content won't clear them. The truck semitrailer is too tall.

 

[AFdude06]

In Trainz Mojave Sub Division, there are only about 3 out of 17 total active crossings with such overhead structure.

If the route is accurate to the usage of such crossings, that would seem to make sense. From editing the route, I remember there were a few gantry crossings in the cities but none in the country. That would fit the theory that they are mostly used on higher traffic roads. As far as height clearance, I can’t say I’ve ever heard of a time a truck collided with one. They probably make the height equal to most other structures that need to fit large trucks (tunnels, bridges, etc.).

 

[JonMyrlennBailey]

If the route is accurate to the usage of such crossings, that would seem to make sense. From editing the route, I remember there were a few gantry crossings in the cities but none in the country. That would fit the theory that they are mostly used on higher traffic roads. As far as height clearance, I can’t say I’ve ever heard of a time a truck collided with one. They probably make the height equal to most other structures that need to fit large trucks (tunnels, bridges, etc.).

It could be some of those Trainz content gantry devices were not drawn to exact real-life scale. Or, some of the drivable truck content was disproportionately tall.

 

[AFdude06]

I wonder if there is a website to learn about the usage of crossings? Except that usage probably varies by city.

 

[AFdude06]

I just found this PDF on the FRA website. Page 11 has some explanation of what is regulation, but it’s not really helpful about the rules for the gantry (I found out they’re also called cantilever) crossings.

EDIT: I discovered this text on toolkits.ite.org. A perfect explanation:

Cantilevered Flashing Light Signals

Flashing light signals are generally post-mounted, but where improved visibility to approaching traffic is required, cantilevered flashing light signals are used. Cantilevered flashing lights may be appropriate when any of the following conditions exist:

• Multilane highways (two or more lanes in one direction).
• Highways with paved shoulders or a parking lane that would require a post-mounted light to be more than 10 feet from the edge of the travel lane.
• Roadside foliage obstructing the view of post-mounted flashing light signals.
• A line of roadside obstacles such as utility poles (when minor lateral adjustment of the poles would not solve the problem).
• Distracting backgrounds such as an excessive number of neon signs (conversely, cantilevered flashing lights should not distract from nearby highway traffic signals).
• Horizontal or vertical curves at locations where the extension of flashing lights over the traffic lane will provide sufficient visibility for the required stopping sight distance.

A typical installation consists of one pair of cantilevered lights on each highway approach, supplemented with a pair of lights mounted on the supporting mast. However, two or more pairs of cantilevered flashing lights may be desirable for multilane approaches, as determined by an engineering study. The cantilevered lights can be placed over each lane so that the lights are mutually visible from adjacent driving lanes.

 

[ricomon35]

I agree on the high traffic spec for these cantilevered gantry masts.

In the town of Beaverton, where I commute through on light-rail regularly.
The high-use crossings have the Canti setups, low use do not.

High use intersections on the MAX Light-Rail Blue line (west side)

Intersection 1
Intersection 2
Intersection 3
Intersection 4
Intersection 5
Intersection 6

Low use, same area
Intersection 7
Intersection 8

If you keep traveling west down the line, you'll see the pattern continues on until the end of line terminal.


Rico