# Gantry (transport)

A gantry (also known as a sign holder, road sign holder, sign structure or road sign structure) is a traffic sign assembly in which signs are mounted or railway signals are supported on an overhead support. They also often contain the apparatus for traffic monitoring systems and cameras, or open road tolling systems.
Gantries are usually built on high-traffic roads or routes with several lanes, where signs posted on the side of the highway would be hard for drivers to see. Gantries may be cantilevered or one-sided on the left, right and center (sometimes referred to as a half-gantry or butterfly gantry), or they may be bridges with poles on each side. Similar gantries are used in railway signalling or to suspend overhead lines on multi-track lines.

## Around the world
### Canada

Gantry signs are commonly used in urban highways in Canada to support overhead signs. Half-gantries are used to place signs near exits where space does not permit having signs to the right side of the roadway. Gantries can also be used to hold cameras for toll road entrances/exits and to hold electronic information signs, such as on Ontario Highway 407. The style of gantry used are mostly truss gantries. Older gantries have truss supports (round or box) and newer ones are now supported by cylindrical legs. In most jurisdictions in Canada, signs that are mounted on overhead gantries are installed perpendicular to the roadway. In Québec, however, signs are angled slightly face-down towards the roadway such that the sign face is directed towards the motorists below. In New Brunswick, the opposite is true: signs are angled slightly face-up to capture and reflect more sunlight towards the roadway.
The colors of the gantry sign may indicate different things in Canada. Generally, the signs are green (similar to the United States) however different colored signs may exist for certain purposes. For example, the Ontario 400 series highway will use green for the inner Express lanes while using dark blue for the outer collector lanes. Another reason for blue signs would be Express Toll Routes (Highway 407 Toll Route utilizes some blue signs at entrances). Finally, overhead blue signs may be used near airports (such as the roads going into Toronto Pearson Airport or Vancouver International Airport).

### Hong Kong

Hong Kong's highways use a gantry crane type to support signs. The road signs are usually located on top and some have lights to indicate open or closed lanes.

### United Kingdom

Gantry signs are being installed at various locations around the trunk motorway network as increasing amounts of traffic mean that road signs at the side of the carriageway are frequently obscured by large goods vehicles. They may also consist of variable-message signs, and more recently Active Traffic Management, to close lanes due to accidents and for other reasons. They can also be used to specify temporary speed limits. Gantries in the United Kingdom display exit (junction) numbers, distances to junctions / exits (1 mile, 1/2 mile, 1/4 mile, 1/3 mile, 3/4 mile, 2/3 mile) and destinations reached, and if necessary what lane to use for them.

### United States

Gantry signs are used frequently in the U.S., particularly in urban areas where freeways have an exit every mile to fit in with the grid system. These half-gantries usually have the exit number and the road or street that can be reached. Gantries can also span the whole road, such as at major junctions.

## Designs

* Truss or latticework designs
* US 98 Dade City
* Electronic toll collection verification of road tax payment by trucks on German controlled-access highways
* Near Houten, Netherlands
* Gantry in the United Kingdom, with access for maintenance
* On the D.815 road in Turkey
* Super-span gantry near Dublin
* Near Malmö, Sweden
* T-shaped, butterfly or pedestal – signs are mounted onto a T-shaped structure
* Pedestal gantry sign in Georgia
* Butterfly gantry near Raubling, Germany
* On the Jakarta Outer Ring Road
* Gantries placed on either side of the carriageway on the A4 autoroute, France
* Tubular pipes – may be round or square in shape
* A tubular piped (monotube) gantry in California
* Cantilevered gantry in Doha, Qatar
* In Dubai
* Rear view of a gantry in Hungary, with access for maintenance
* Near Frankfurt Airport
* Other designs
* Terminal East gantry sign at Denver International Airport with an empty freeway during the pandemic.
* Older UK gantry, with concrete posts, near Ewloe, Wales

## Railway use

On railways, gantries span multiple railway tracks and carry either railway signals, overhead lines or both. A signal gantry is also used where to improve the visibility of multiple signals, for example around a sharp curve.

### Gallery of railway gantries

* A gantry of British semaphore signals seen from the cab of a steam locomotive
* Gantry with old and new suspended equipment at Grivita railway station, Bucharest.
* Signal gantry in Glasgow Central Station
* Overhead line gantry in Denmark
* 4-track section of Amtrak's Northeast Corridor in New Jersey
* Railway overhead line electification gantry Church Road Tottenham London England
* Gantry at Gare Saint-Lazare
* Gantry of Sri Lanka semaphore signals