US Bridges

US 287 over RR

Fair

Gallatin County, Montana · 11M SW Three Forks · Structure no. P00013082+04411

Built
1950
75 years old
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
374 ft
8 main spans
Daily traffic
1,227
2023 count
Owner
State
State Highway Agency

About this bridge

US 287 over RR is a steel continuous stringer/multi-beam or girder carrying US 287 over RR in Gallatin County, Montana. It was built in 1950, so it is 75 years old, older than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 1,227 vehicles a day, roughly 13% of them trucks, projected to reach 1,288 by 2043. The structure is 374 ft (114 m) long and 30 ft wide. If it were closed, the detour would be 52.2 mi (84 km).

Location

Open in Google Maps
CarriesUS 287
CrossesRR
Location11M SW Three Forks
RouteU.S. Route 287
CountyGallatin County
StateMontana
Coordinates45.79481, -111.75345
Functional classRural Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating42 US tons
Inventory rating33 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans8
Design loadHS 15
Structure length374 ft (114 m)
Longest span54 ft (16.5 m)
Deck width30 ft (9 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,227 (2023)
Projected traffic1,288 by 2043
Trucks13%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesRailroad
Detour if closed52.2 mi (84 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was US 287 over RR built?

It was built in 1950, making it 75 years old in 2025.

What condition is US 287 over RR in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in May 2023.

How much traffic does US 287 over RR carry?

About 1,227 vehicles per day (2023 count), of which roughly 13% are trucks.

How long is US 287 over RR?

The structure is 374 ft (114 m) long with a longest span of 54 ft (16.5 m) and a deck 30 ft wide.

Who owns US 287 over RR?

It is owned by the State Highway Agency.